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Gieysztoria beltrani (Gieysztor, 1931) Ruebush & Hayes, 1939 (Fig. 8 D) syn. Dalyellia beltrani Gieysztor, 1931 syn. Microdalyellia beltrani Ruebush & Hayes, 1939 New localities in Spain. Do��ana National Park, Provincia de Huelva, Spain (36 �� 49 ��� 27 ���N, 6 �� 21 ��� 40 ���W). Llanos del Taraje near Ecomuseo Robledo de la Plancha: muddy temporal pond with Ranunculus aquatilis and sedges (25 /03/ 2008). Do��ana National Park, Provincia de Huelva, Spain (37 ��04��� 23 ���N, 6 �� 22 ��� 28 ���W). Laguna de la FAO: permanent water body with submersed vegetation (05/04/ 2008). Do��ana National Park, Provincia de Huelva, Spain (36 �� 58 ��� 50 ���N, 6 �� 29 ��� 11 ���W). Laguna Dulce: swamp vegetation on the northern edge and floating algae and submersed vegetation on the border of the marsh and open water (06/04/ 2008). Do��ana National Park, Provincia de Huelva, Spain (36 �� 59 ���26.53���N, 6 �� 26 ���32.16���W). Marsh with Ranunculus aquatilis, Calla palustris and sedges near El Palacio (06/04/ 2008). Other localities in Spain. Central areas (Sierra de Guadarrama and river Tajo basin, see Gamo & Nore��a- Janssen 1998); Navaescurial (Provincia de Avila, Castilla y Le��n) (Gamo & Mayor 1987), La Albufera and el Jard��n bot��nico de Valencia (Provincia de Valencia, Comunidad Valenciana) (Gieysztor 1931). New locality outside Spain. D��partement du Var, Provence-Alpes-C��te d���Azur, France. Dry mud from a temporal pond provided by Dr. Alain Thi��ry (09/ 2007) and hatched at Hasselt University (Belgium) (10 / 2007) Material. Observations on live animals and several whole mounts from Andalusia. Studies on live specimens and three whole mounts from France. Remarks. The animals from Andalusia are between 0.9 and 1.1 mm. The stylet is 119���134 ��m long and consists of two parts of equal length: a proximal girdle with a fenestra and a distal part with spines (���Fenestratae��� subgroup, ���Inaequales��� group of the Gieysztoria- type in Luther 1955, see also Discussion of G. iberica n. sp.), which corresponds completely with the stylet from Gieysztoria beltrani (Gieysztor, 1931) Ruebush & Hayes, 1939, as described by Gieysztor (1931) and Luther (1955). This species has only been found in some localities in eastern and central Spain (Gieysztor 1931; Gamo & Mayor 1987; Gamo & Nore��a-Janssen 1998). The animals from eastern Spain measured 0.9���1.4 mm, while the French animals attained a length of 1 ���1.3 mm. The stylet length of the specimens from Andalusia also falls within the range of other observations from this species (southern France: 125���139 ��m; eastern Spain: 100���125 ��m; central Spain: 130 ��m) (see Gieysztor 1931; Gamo & Mayor 1987; own observations). Since records from other parts of Europe are lacking, G. beltrani seems to be preliminarily confined to permanent and temporal freshwater bodies of the Western Mediterranean region., Published as part of Steenkiste, Niels Van, Tessens, Bart, Krznaric, Kathleen & Artois, Tom, 2011, Dalytyphloplanida (Platyhelminthes: Rhabdocoela) from Andalusia, Spain, with the description of four new species, pp. 1-29 in Zootaxa 2791 on pages 22-23, DOI: 10.5281/zenodo.201106, {"references":["Gieysztor, M. (1931) Contribution a la connaissance des Turbellaries Rhabdoceles (Turbellaria Rhabdocoela) d'Espagne. Bulletin de l'Academie Polonaise des Sciences et des Lettres, Classe des Sciences Mathematiques et Naturelles. Serie B: Sciences Naturelles (II), 1931, 125 - 153.","Ruebush, T. K. & Hayes, W. J. (1939) The genus Dalyellia in America II. A new form from Tennessee and a discussion of the relationships within the genus. Zoologischer Anzeiger, 128, 136 - 152.","Gamo, J. & Mayor, I. (1987) Microturbelarios nuevos para la fauna iberica. VIII Bienal de la Real Sociedad Espanola de Historia Natural, Actas 23, Pamplona, 23 - 28.","Luther, A. (1955) Die Dalyelliiden (Turbellaria, Neorhabdocoela). Eine Monographie. Acta Zoologica Fennica, 87, 1 - 337.","Gamo, J. & Norena-Janssen, C. (1998) Old and new records of turbellarians from the central areas of Spain. Hydrobiologia, 383, 299 - 305."]}

Castrella truncata (Abildgaard, 1789) Hofsten, 1907 (Fig. 8 A) syn. Planaria truncata Abildgaard, 1789 syn. Derostoma truncatum (Abildgaard, 1789) Dug��s, 1830 syn. Vortex truncatus (Abildgaard, 1789) Ehrenberg, 1831 syn. Vertex truncatus (Abildgaard, 1789) Ehrenberg, 1836 syn. Vortex intermedius Du Plessis, 1879 syn. Vortex millportianus Graff, 1882 syn. Vortex quadrioculatus Vejdovsky, 1895 syn. Castrella agilis Fuhrmann, 1900 syn. Castrella quadrioculatus (Vejdovsky, 1895) Fuhrmann, 1900 syn. Castrella millportiana (Graff, 1882) Fuhrmann, 1900 syn. Castrella serotina D��rner, 1902 syn. Vortex obscurus Plotnikow, 1905 syn. Castrella bologowiensis Plotnikow, 1906 syn. Castrella quadrioculata (Vejdovsky, 1895) Sekera, 1907 syn. Dalyellia truncata (Abildgaard, 1789) Graff, 1904 ���1908 syn. Dalyellia intermedia (Du Plessis, 1879) Graff, 1904 ���1908 syn. Dalyellia millportianus (Graff, 1882) Graff, 1904 ���1908 syn. Jensenia truncata (Abildgaard, 1789) Graff, 1904 ���1908 syn. Jensenia obscura (Plotnikow, 1905) Graff, 1904 ���1908 syn. Jensenia agilis (Fuhrmann, 1900) Graff, 1904 ���1908 syn. Jensenia serotina (D��rner, 1902) Graff, 1904 ���1908 syn. Jensenia quadrioculata (Vejdovsky, 1895) Graff, 1904 ���1908 syn. Jensenia intermedia (Du Plessis, 1879) Graff, 1904 ���1908 syn. Jensenia millportiana (Graff, 1882) Graff, 1904 ���1908, Published as part of Steenkiste, Niels Van, Gobert, Stefan, Davison, Paul, Kolasa, Jurek & Artois, Tom, 2011, Freshwater Dalyelliidae from the Nearctic (Platyhelminthes, Rhabdocoela): new taxa and records from Ontario, Canada and Michigan and Alabama, USA, pp. 1-32 in Zootaxa 3091 on page 26, DOI: 10.5281/zenodo.207604, {"references":["Abildgaard, P. C. (1789) In: Muller, O. F. (Ed.), Zoologia Danica, seu animalium Daniae et Norvegiae rariorum ac minus notorum descriptiones et historia. Havniae, 3, pp. 75.","Hofsten, N. von (1907) Studien uber Turbellarien aus dem Berner Oberland. Zeitschrift fur Wissenschaftlichen Zoologie, 85, 391 - 654.","Duges, A. (1830) Apercu de quelques observations nouvelles sur les Planaires et sur plusieurs genres voisins. Annales des Sciences Naturelles, 21, 72 - 90.","Ehrenberg, C. G. (1831) Phytozoa turbellaria Africana et Asiatica in Phytozoorum Tabula IV et V delineata. In: Hemprich, F. G. & Ehrenberg, C. G. (Eds), Symbolae physicae, seu icones et descriptiones corporum naturalium novorum aut minus cognitorum quae ex itineribus per Libyam, Aegyptium, Nubiam, Dongalum, Syriam, Arabiam, et Habessiniam, pars zoologica II, animalia evertebrata exclusis insectis. Officina Academica, Berolina, pp. 53 - 67, pls IV - V (plates published in 1828, text in 1831).","Ehrenberg, C. G. (1836) Die Akalephen des rothen Meeres und der Organismus der Medusen der Ostsee erlautert und auf Systematik angewendet. Abhandlungen der Koniglichen Akademie der Wissenschaften zu Berlin, 1836, 67.","Du Plessis, G. (1879) Sur quelques nouveaux Turbellaries de la faune profonde du Lac Leman. Bulletin de la Societe Vaudoise des Sciences Naturelles, 16, 157 - 160.","Graff, L. von (1882) Monographie der Turbellarien I. Rhabdocoelida. Text + Atlas, Leipzig, 442 pp., 20 t.","Vejdovsky, F. (1895) Zur vergleichenden Anatomie der Turbellarien. (Zugleich ein Beitrag zur Turbellarienfauna Bohmens). Zeitschrift fur Wissenschaftlichen Zoologie, 60, 90 - 162.","Fuhrmann, O. (1900) Note sur les Turbellaries des environs de Geneve. Revue suisse de Zoologie, 7, 717 - 731.","Dorner, G. (1902) Darstellung der Turbellarienfauna der Binnengewasser Ostpreussens. Schriften der Physikalische-okonomischen Gesellschaft zu Konigsberg, 43, 1 - 58.","Plotnikow, W. (1905) Uber einige rhabdocoele Turbellarien Sibiriens. Zoologische Jahrbucher - Abteilung fur Systematik, Okologie und Geographie der Tiere, 21, 479 - 490.","Plotnikow, W. (1906) Zur Kenntnis der Susswasser-Wurmer-Fauna der Umgebung von Bologoje. Berichte der biologischen Susswasserstation der Kaiserlichen Naturforscher-Gesellschaft zu St. - Petersburg, 2, 1 - 41.","Sekera, E. (1907) Zur Biologie einiger Wiesentumpel. Archiv fur Hydrobiologie, 2, 347 - 354.","Graff, L. von (1904 - 1908) Acoela und Rhabdocoelida. In: Bronn, H. G. (Ed.), Klassen und Ordnungen des Thierreichs, Band IV (Vermes), Abtheilung Ic (Turbellaria), C. F. Winter'sche Verlagshandlung, Leipzig, pp. I - XXII + 1733 - 2599, Tafel I - XXX."]}

Parapharyngiella involucrum Willems et al., 2005 (Figs. 1 A��� 1 D) New locality. Do��ana National Park, Provincia de Huelva, Spain (36 �� 52 ��� 40 ���N, 6 �� 22 ���03���W). Salinas de San Rafael: small algae in shallow, brackish pools of abandoned salt pans (25 /03/ 2008). Known distribution. Western Indian Ocean (Tanzania: Zanzibar) (Willems et al. 2005). Material. Observations on a live animal that was subsequently whole-mounted. Type material from Proxenetes mackfirae Karling, 1978 (SMNH, no. 42498) and Parapharyngiella involucrum Willems et al., 2005 (HU, nos. 281���283) for comparison. Remarks. The animal is about 0.4���0.5 mm long. The pharynx is at 50���60 % of the body length. The two testes lie anterolaterally from the pharynx. The genital system is situated in the caudal body half. The stylet (Fig. 1 C) is almost identical to that of the specimens from Zanzibar. It measures about 30 ��m at its widest and is 60 ��m long. It consists of a semicircular tube with a funnel-shaped base and a curved distal point (j); a curved, slender protrusion with a bluntly-rounded distal end (k); a mantle with a straight proximal rim and a distal hook encompassing the distal half of the semicircular tube (l). The bursal canal (Fig. 1 B) (bursal stalk in Willems et al. 2005) is sclerotized and about 52 ��m long. It seems to connect the male or common genital atrium with the bursa. When entering the bursa it broadens to become slightly funnel-shaped. The bursal appendage (Fig. 1 D) is not clearly visible in the whole mount. It is about 30 ��m long and seems to consist of a pyriform to club-shaped proximal part, 10 ��m long originating on the bursa, and a slender distal tube of 20 ��m. Both parts appear to be separated by a sphincter. The tubular part seems provided with a very thick tissue, of which the exact origin could not be determined. It could not be seen whether it connects the bursa to the female duct as described by Willems et al. (2005) or not. Discussion. When considering the different structures of the genital system visible in the live specimen and the whole mount, the Spanish specimen agrees with those from Zanzibar. Parapharyngiella involucrum is a monotypic taxon within the Trigonostomidae Graff, 1905. The stylet, although slightly smaller and with a less slender distal hook than in the animals from Zanzibar (�� 50 ��m long), is almost identical to that of the Zanzibar specimens (see Willems et al. 2005). Both populations have a sclerotized bursal canal between the male or common genital atrium and the bursa, and a slender tubiform bursal appendage with a club-shaped base. In the Tanzanian specimens the latter tube connects the bursa with a sperm-containing vesicle on the female duct, but this could not be seen in the animal from Spain. One difference concerns the position of the pharynx and the genital organs. While all reproductive structures of the East African specimens are located just behind the pharynx (which is situated in the first body half), male and female organs of the Andalusian specimen occupy a large fraction of the caudal body half behind the centrallylocated pharynx. Despite this difference and awaiting the availability of new material, we prefer to preliminarily assign the specimen from Spain to P. involucrum. The stylet is also very similar to that of Proxenetes mackfirae from Bermuda (see Karling 1978). Although the stylet of this taxon is somewhat larger (70���100 ��m), it also consists of a semicircular tube and a slender hooked mantel, a feature unique within Proxenetes Jensen, 1878. Obvious differences distinguish P. mackfirae from Parapharyngiella involucrum. Compared with the protrusion of the stylet of P. i n v o l u c r u m (k in Fig. 1 C), the protrusion of P. mackfirae is longer, more pointed and connected with a cup-shaped membrane with its distal border cut out in a right angle. This membrane is lacking in P. involucrum. Minor differences are to be found in a longer bursal canal (�� 80 ��m) in P. m a c k f i r a e and the bursal appendage that seems to lack a thickened wall in the species from Bermuda. Although the construction of the stylet and the presence of a tubular bursal canal (internal vagina in Karling 1978) and a funnel-shaped, double-barrelled bursal appendage as described above, seem clear indications of its kinship with Parapharyngiella, we refrain from transferring P. mackfirae to this taxon because the female system of this species has not been described., Published as part of Steenkiste, Niels Van, Tessens, Bart, Krznaric, Kathleen & Artois, Tom, 2011, Dalytyphloplanida (Platyhelminthes: Rhabdocoela) from Andalusia, Spain, with the description of four new species, pp. 1-29 in Zootaxa 2791 on pages 2-4, DOI: 10.5281/zenodo.201106, {"references":["Karling, T. G. (1978) Anatomy and systematics of marine Turbellaria from Bermuda. Zoologica Scripta, 7, 225 - 248.","Graff, L. von (1905) Turbellaria I. Acoela. In: Schulze, F. E. (Ed.), Das Tierreich 23. Konigliche Preussische Akademie der Wissenschaften, Berlin, pp. 34.","Jensen, O. S. (1878) Turbellaria ad litora Norvegiae occidentalia (Turbellarier ved Norges vestkyst). J. W. Eides Bogtrykkeri, Bergen, 97 pp."]}

Castrada infernalis Papi, 1951 New locality. Do��ana National Park, Provincia de Huelva, Spain (36 �� 49 ��� 27 ���N, 6 �� 21 ��� 40 ���W). Llanos del Taraje near Ecomuseo Robledo de la Plancha: muddy temporal pond with Ranunculus aquatilis and sedges (25 /03/ 2008). Other localities in Spain. Central areas (Sierra de Guadarrama and river Tajo basin, see Gamo & Nore��a- Janssen 1998); Congostrina (Provincia de Guadalajara, Castilla-La Mancha) (Gamo 1987 b), Bele��a lagoons (Provincia de Guadalajara, Castilla-La Mancha) (Gamo & Schwank 1987), Alburquerque (Provincia de Badajoz, Extremadura) and C��ceres (Provincia de C��ceres, Extremadura) (Nore��a et al. 1999). Known distribution. Palearctic: Southern Europe (Italy) (Papi 1951, 1954). Material. Observations on a live animal. Remarks. The animal is transparent and colourless. Rostrally, the typical darkly-stained pigment spots are visible in transmitted light. The pharynx is situated between 40 and 50 %. The male system consists of an atrium copulatorium receiving the oviform copulatory bulb, a large blind sac with small proximal spines and large, slender distal spines, and a copulatory bursa without bursal stalk and armed with small spines. The ejaculatory duct is a thick-walled funnel, proximally curled inwards. Of the female system, only the ovary could be observed, flanking the male system at one side. Although an accessory bursa has not been observed, all other features, including the lack of zoochlorellae, the pigmented spots in the front, the organization of the male system and the armature of the blind sac in particular, are diagnostic for C. infernalis Papi, 1951. Papi (1954) also describes the subspecies C. infernalis breviorispina Papi, 1954, from the same region in Italy as C. infernalis. It only differs from C. infernalis by shorter spines in the blind sac of the atrium copulatorium, smaller spines in the copulatory bursa, a double sphincter separating the atrium copulatorium and the common genital atrium, and less pigment in the front end of the body. This subspecies has also been found in central Spain (see Gamo 1987 b). Since the spines of the specimen from Andalusia have not been measured and the sphincter around the atrium copulatorium has not been observed, its infraspecific taxonomic position could not be established. Discussion of Castrada. Based on the position of the nephridiopores, Nasonov (1926) has split the taxon Castrada into Castrada and Castradella (Nasonov, 1926) Luther, 1963, whereas Luther (1963) lumped them back together as subgenera of the genus Castrada. Awaiting a thorough cladistical analysis, we adopt Luther���s (1963) classification. The position of the taxon Castrada and the closely related taxa Mesocastrada Volz, 1898, Tetracelis Ehrenberg, 1831, Papiella Mack-Fira, 1970 a and Rhynchomesostoma Luther, 1904, has been controversial (for a discussion see Papi 1959; Mack-Fira 1970 a; and more recently Willems et al. 2005 and Nore��a et al. 2008). Formerly placed within the Typhloplaninae (Castrada, Castradella, Mesocastrada), Olisthanellinae Luther, 1904 (Papiella) and even the Protoplanellinae (Castradella), these taxa are now considered representatives of the Rhynchomesostominae Bresslau, 1933 because of the construction of the genital system, and in particular the presence of an atrium copulatorium (Papi 1959; Mack-Fira 1970 a). The position of Tetracelis remains unclear. Most authors (including Luther 1963; Tyler et al. 2006���2010, web reference [2]; Nore��a et al. 2008) put Tetracelis within the Typhloplaninae, but Papi (1959) and Mack-Fira (1970 a) conjecture a close relationship with the above-mentioned taxa because of the presence of an atrium copulatorium. With nephridiopores opening in the buccal tube, C. purgatorialis n. sp. and C. paradisea n. sp. clearly belong to the nominal subtaxon Castrada. Main differences between these two new species include the armature of the atrium copulatorium and its blind sac, the appearance of the ejaculatory duct and the presence of spermatophores in the copulatory bursa. Few species of Castrada have the combination of an accessory bursa and one spiny blind sac in the atrium copulatorium. Only C. infernalis and C. viridis Volz, 1898 share these characters. C. viridis differs from C. purgatorialis n. sp. in the fact that it has uniform, small spines in the blind sac and a less-developed accessory bursa, and from C. paradisea n. sp. by the presence of zoochlorellae in C. viridis. C. purgatorialis n. sp. strongly resembles C. infernalis (and its subspecies C. infernalis subsp. breviorispina Papi, 1954), because of the combination of large and small spines in the blind sac of the atrium copulatorium, and the presence of a well-developed accessory bursa. It differs from C. infernalis by lacking the dark, pigmented spots in the front end of the body typical for this latter species. Moreover, C. purgatorialis has zoochlorellae and bursal vesicles, which are absent in C. infernalis. The two species also have a different granular secretion of the accessory bursa (eosinophilic in C. infernalis, while basophilic in C. purgatorialis n. sp.; see Papi 1951, 1954). Other species within the subtaxon Castrada having large spines or teeth in the atrium copulatorium all lack an accessory bursa (C. chlorea Braun, 1885, C. cristatispina Papi, 1951, C. multispina Nore��a et al., 2008, C. neocomensis Volz, 1898, C. sphagnetorum Luther, 1904 and C. trispina Willems et al., 2005). C. quadridentata Hofsten, 1907 could also be included in this list, but it is not clear whether this species belongs to Castrada or Castradella. Moreover, whether this species has an accessory bursa or not, is not known (Hofsten 1907; Luther 1963). The seminal receptacle of C. purgatorialis n. sp., consisting of large nucleated cells, strongly resembles that of C. montana Papi, 1959 (see Papi 1959). However, the latter species differs in many other features including the lack of zoochlorellae and the general organization of the genital system (e.g. sphincter partitioning the common genital atrium, atrium copulatorium with two small blind sacs provided with small ���allineated pseudocuticular bodies���, no accessory bursa; see Papi 1959). A number of mostly poorly described taxa of Castrada share some common features of the male genital system with C. paradisea n. sp. (one blind sac, uniform spines and a simple ejaculatory duct). C. spinulosa Hofsten, 1907 is similar to C. paradisea n. sp., but has a stalked seminal receptacle in the female system. C. horrida Schmidt, 1861 is also poorly known, but lacks spermatophores and an accessory bursa. C. subsalsa Luther, 1946 is only known from brackish habitats and also lacks an accessory bursa and has no spines in the copulatory bursa. As many species of Castrada lack a detailed description, identification and morphological comparison of specimens is often difficult. Many species may possibly consist of species complexes or could be lumped in one large species pool. A thorough molecular analysis would probably help to unravel the complex evolutionary history of this taxon, and help species delimitation and identification., Published as part of Steenkiste, Niels Van, Tessens, Bart, Krznaric, Kathleen & Artois, Tom, 2011, Dalytyphloplanida (Platyhelminthes: Rhabdocoela) from Andalusia, Spain, with the description of four new species, pp. 1-29 in Zootaxa 2791 on pages 13-14, DOI: 10.5281/zenodo.201106, {"references":["Papi, F. (1951) Uber einige Typhloplaninen (Turbellaria Neorhabdocoela). Acta Zoologica Fennica, 64, 1 - 20.","Gamo, J. (1987 b) Microturbelarios nuevos o poco conocidos de la fauna Iberica. Actas del IV Congreso Espanol de Limnologia, 385 - 392.","Gamo, J. & Schwank, P. (1987) One new species of Castrada (Turbellaria Neorhabdocoela) and four new records of Microturbellarians in the Iberian Peninsula. Archiv fur Hydrobiologie, 110, 605 - 615.","Norena, C., del Campo, A. & del Real, M. (1999) Taxonomy and morphology of limnic microturbellarians (Platyhelminthes) in Extremadura (Spain). Hydrobiologia, 397, 21 - 28.","Papi, F. (1954) Aspetti del differenziamento razziale e specifico nei Turbellari Rabdoceli. Bollettino di Zoologia, 21, 357 - 377.","Nasonov, N. (1926) Die Turbellarienfauna des Leningrader Gouvernements. Bulletin de l'Academie des Sciences de l'URSS, 1926, 817 - 884.","Luther, A. (1963) Die Turbellarien Ostfenoskandiens IV. Neorhabdocoela 2. Typhloplanoida: Typhloplanidae, Solenopharyngidae und Carcharodopharyngidae. Fauna Fennica, 16, 1 - 163.","Volz, W. (1898) Uber neue Turbellarien aus der Schweiz. Zoologischer Anzeiger, 21, 605 - 612.","Ehrenberg, C. G. (1831) Phytozoa turbellaria Africana et Asiatica in Phytozoorum Tabula IV et V delineata. In: Hemprich, F. G. & Ehrenberg, C. G. (Eds.), Symbolae physicae, seu icones et descriptiones corporum naturalium novorum aut minus cognitorum quae ex itineribus per Libyam, Aegyptium, Nubiam, Dongalum, Syriam, Arabiam, et Habessiniam, pars zoologica II, animalia evertebrata exclusis insectis. Officina Academica, Berolina, pp. 53 - 67, pls IV - V (plates published in 1828, text in 1831).","Mack-Fira, V. (1970 a) Sur la position systematique de l'espece Castradella otophtalma (Plotnikov 1906). Revue Roumaine de Biologie (Zoologie), 15, 3 - 10.","Luther, A. (1904) Die Eumesostominen. Zeitschrift fur Wissenschaftliche Zoologie, 77, 1 - 273.","Papi, F. (1959) Ricerche su alcuni generi affini della fam. Typhloplanidae (Turbellaria Neorhabdocoela). Archivo Zoologico Italiano, 44, 1 - 51.","Norena, C., Eitam, A. & Blaustein, L. (2008) \" Microturbellarian \" flatworms (Platyhelminthes) from freshwater pools: new species and records from Israel. Zootaxa, 1705, 1 - 20.","Bresslau, E. (1933) Turbellaria. In: Kukenthal, W. & Krumbach, T. (Eds.), Handbuch der Zoologie. Eine Naturgeschichte der Stamme der Tierreiches. Band II. Walter De Gruyter & Co., Leipzig, pp. 52 - 304.","Braun, M. (1885) Die Rhabdocoeliden Turbellarien Livlands. Ein Beitrag zur Anatomie, Systematik und geographischen Verbreitung dieser Tiere. Archiv fur die Naturkunde, Liv-, Ehst- und Kurlands Serie II, 10, 1 - 125.","Hofsten, N. von (1907) Studien uber Turbellarien aus dem Berner Oberland. Zeitschrift fur Wissenschaftlichen Zoologie, 85, 391 - 654.","Schmidt, O. (1861) Untersuchungen uber Turbellarien von Corfu und Cephalonia. Nebst Nachtragen zu fruheren Arbeiten. Zeitschrift fur Wissenschaftlichen Zoologie, 11, 1 - 30, pls. I - IV.","Luther, A. (1946) Untersuchungen an Rhabdocoelen Turbellarien - Uber einige Typhloplaniden. Acta Zoologica Fennica, 46, 3 - 56."]}

Microdalyellia armigera (Schmidt, 1861) Gieysztor, 1938 a (Fig. 8 A) syn. Vo rt e x a r m i ge r Schmidt, 1861 syn. Dalyellia armiger Graff, 1904 ���1908 syn. Dalyellia armigera Hofsten, 1912 syn. Dalyellia armygera Valkanov, 1926 syn. Microdalyellia armiger Gieysztor, 1938 a New locality in Spain. Do��ana National Park, Provincia de Huelva, Spain (36 �� 58 ��� 50 ���N, 6 �� 29 ��� 11 ���W). Laguna Dulce: swamp vegetation on the northern edge and floating algae and submersed vegetation on the border of the marsh and open water (19 /03/ 2008; 06/04/ 2008). Other localities in Spain. Central areas (Sierra de Guadarrama and river Tajo basin, see Gamo & Nore��a- Janssen 1998); Corpa (Provincia de Madrid, Comunidad de Madrid), Fuentenovilla and Cogolludo (Provincia de Guadalajara, Castilla-La Mancha) (Gamo 1987 a, 1987 b). New localities outside Spain. Palearctic: Stekene, East Flanders, Belgium (51 �� 14 ��� 26 ���N, 04��05��� 26 ���E; 51 �� 14 ��� 25 ���N, 04��05��� 29 ���E; 51 �� 14 ��� 32 ���N, 04��05���03���E). Stropers: aquatic vegetation in ditches and temporal ponds along the forest edge (13 /07/ 2008). Genk, Limburg, Belgium (50 �� 55 ��� 30 ���N, 05�� 23 ��� 39 ���E; 50 �� 57 ��� 21 ���N, 05�� 27 ��� 41 ���E). De Maten: submersed aquatic vegetation (grasses and Mentha aquatica) from a pond and the Stiemerbeek (17 /07/ 2008). Kampenhout, Flemish Brabant, Belgium (50 �� 55 ��� 40 ���N, 04�� 31 ��� 19 ���E). Hellebos: submersed grasses from a ditch (09/03/ 2009). Opoeteren, Limburg, Belgium. Area of the Bosbeek: floating vegetation from a puddle with lots of pine needles and leaf litter (18 /05/ 2009). Seckauer Tauern, Niedere Tauern, Styria, Austria (47 �� 20 ��� 39 ���N, 14 �� 53 ��� 14 ���E, alt. 1315 m; 47 �� 20 ��� 39 ���N, 14 �� 53 ��� 22 ���E, alt. 1330 m). Valley north of Krautbath: aquatic vegetation in a small, shallow pond along the side of a track fed by a mountain stream; aquatic vegetation in marshy areas on the end of the track (23 /06/ 2009). S��lkt��ler Nature Park, Schladminger Tauern, Niedere Tauern, Styria, Austria (47 �� 17 ��� 17 ���N, 13 �� 52 ���01���E, alt. 1218 m). Schwarzensee near Kleins��lk: aquatic vegetation and mosses in a Sphagnum bog fed by a mountain stream southwest of the Schwarzensee (27 /06/ 2009). Gleinalpe, Lavanttal Alps, Styria, Austria (47 �� 13 ��� 50 ���N, 14 �� 58 ��� 57 ���E, alt. 1464 m). Glein Rachau: aquatic vegetation in mountain stream (29 /06/ 2009). Sumava National Park, South Bohemian Region, Czech Republic (48 �� 58 ��� 13 ���N, 13 �� 35 ��� 19 ���E, alt. 1216 m). Bogs and coniferous forests around Bučina: aquatic vegetation in forested Sphagnum bog (02/07/ 2009). Palatinate Forest Nature Park, Rhineland-Palatinate, Germany (49 �� 17 ��� 20 ���N, 07�� 49 ��� 14 ���E, alt. 536 m). Forests east of Leimen: moss and organic material in forest spring (04/08/ 2009). Longsk��r, Raseborg, Uusimaa, Finland (59 �� 49 ���09���N, 23 �� 15 ��� 36 ���E). Submersed grasses in freshwater lake (07/ 08/ 2008). Pojo, Raseborg, Uusimaa, Finland (60 ��05��� 30 ���N, 23 �� 31 ��� 46 ���E). Mosses along small canal close to water edge (10 /08/ 2008). Known distribution. Widespread throughout the Palearctic: many localities in Europe, Western Russia, the Caucasus, Siberia and Japan (see Luther 1955 for localities and references), Western Europe (UK: East Midlands, East of England, West Midlands and North Wales) (Young 1970, 1973), Central Europe (Germany: Schleswig-Holstein, Black Forest, Lake Constance, Thuringia, Franconia, Oberhessen, South Lower Saxony, Elbe estuary; Austria: Burgenland) (Rixen 1961, 1965, 1968; Kraus 1965; P��rner 1966; Bauchhenss 1971; Schwank 1976, 1981, 1985; Heitkamp 1982; M��ller & Faubel 1993), Eastern Europe (Romania: freshwater sources of littoral lakes of the Black Sea, Bucegi Mountains, Retezat Mountains, Wallachian Plain; Poland: Greater Poland Province) (Mack-Fira 1970 b; Kolasa 1974), Western Russia (Northern Dvina River and upper Volga River) (Korgina 1999, 2002) and the Middle East (Israel) (Nore��a et al. 2008); Nearctic: localities in the USA uncertain according to Ruebush (1937). Material. Studies on live animals from Spain of which two were whole mounted. Observations on live animals from the other new localities and several whole mounts (14 from Belgium, 7 from Austria, 2 from the Czech Republic, 1 from Germany, 1 from Finland). Remarks. Animals from Andalusia are translucent, with a reddish colour frontally. Habitus and internal organization as described by Luther (1955). The characteristic stylet is about 165 ��m long. The left distal axis consists of one spine in the whole mounts, but two spines were observed in a live specimen. The right distal axis bears eight spines, the most proximal one being the largest. The length range of the stylet of other palearctic populations usually varies between 82���125 ��m (see Luther 1955; Rixen 1961; Bauchhenss 1971). Only the specimens from the Elbe estuary (M��ller & Faubel 1993) and Microdalyellia armigera var. vinculosa (Szynal, 1933) Gieysztor, 1938 a from Franconia (Germany) (Bauchhenss 1971) and the Western and Eastern Carpathians (Szynal 1933; Gieysztor & Szynal 1939; Luther 1955), have considerably larger stylets (between 125���220 ��m). As stated by Luther (1955) and other authors (see e.g. Bauchhenss 1971; M��ller & Faubel 1993), the number of spines on the right distal axis (even within the same population) can range between three and nine. Also on the left distal axis, more than one spine can be present (up to four in Bauchhenss 1971). Its variable stylet morphology and widespread occurrence and abundance in many different types of freshwater habitats suggest a complex evolutionary history., Published as part of Steenkiste, Niels Van, Tessens, Bart, Krznaric, Kathleen & Artois, Tom, 2011, Dalytyphloplanida (Platyhelminthes: Rhabdocoela) from Andalusia, Spain, with the description of four new species, pp. 1-29 in Zootaxa 2791 on pages 19-20, DOI: 10.5281/zenodo.201106, {"references":["Schmidt, O. (1861) Untersuchungen uber Turbellarien von Corfu und Cephalonia. Nebst Nachtragen zu fruheren Arbeiten. Zeitschrift fur Wissenschaftlichen Zoologie, 11, 1 - 30, pls. I - IV.","Gieysztor, M. (1938 a) Systematisch-anatomische Untersuchungen an Turbellarien Polens. Zoologica Poloniae, 2, 215 - 248.","Graff, L. von (1904 - 1908) Acoela und Rhabdocoelida. In: Bronn, H. G. (Ed.), Klassen und Ordnungen des Thierreichs, Band IV (Vermes), Abtheilung Ic (Turbellaria), C. F. Winter'sche Verlagshandlung, Leipzig, pp. I - XXII + 1733 - 2599, Tafel I - XXX.","Hofsten, N. von (1912) Revision der schweizerischen Rhabdocoelen und Alloocolen. Revue suisse de Zoologie, 20, 543 - 687.","Valkanov, A. (1926) Beitrag zur Susswasserfauna Bulgariens. Arbeiten der Bulgarischen naturforschenden Gesellschaft, 12, 183 - 186.","Gamo, J. (1987 a) Microturbelarios de la Peninsula Iberica. Miscellania Zoologica, 11, 41 - 49.","Gamo, J. (1987 b) Microturbelarios nuevos o poco conocidos de la fauna Iberica. Actas del IV Congreso Espanol de Limnologia, 385 - 392.","Luther, A. (1955) Die Dalyelliiden (Turbellaria, Neorhabdocoela). Eine Monographie. Acta Zoologica Fennica, 87, 1 - 337.","Young, J. O. (1970) British and Irish freshwater Microturbellaria: historical records, new records and a key for their identification. Archiv fur Hydrobiologie, 67, 210 - 241.","Young, J. O. (1973) The occurrence of Microturbellaria in some British lakes of diverse chemical content. Archiv fur Hydrobiologie, 72, 202 - 224.","Rixen, J. - U. (1961) Kleinturbellarien aus dem Litoral der Binnengewasser Schleswig-Holsteins. Archiv fur Hydrobiologie, 57, 464 - 538.","Rixen, J. - U. (1965) Einige Turbellarienfunde aus dem Hochschwarzwald. Beitrage zur naturkundlichen Forschung in Sudwestdeutschland, 24, 137 - 141.","Rixen, J. - U. (1968) Beitrag zur Kenntnis der Turbellarienfauna des Bodenseegebietes. Archiv fur Hydrobiologie, 64, 335 - 365.","Kraus, H. (1965) Zur Turbellarienfauna des Seewinkels im Neusiedlerseegebiet. Wissenschaftliche Arbeiten aus dem Burgenland, 32, 60 - 115.","Porner, H. (1966) Die rhabdocoeliden Turbellarien der Gewasser von Jena und Umgebung. Limnologica, 4, 27 - 44.","Bauchhenss, J. (1971) Die Kleinturbellarien Frankens. Ein Beitrag zur Systematik und Okologie der Turbellaria excl. Tricladida in Suddeutschland. Internationale Revue der gesamten Hydrobiologie und Hydrographie, 56, 609 - 666.","Schwank, P. (1976) Quantitative Untersuchungen an litoralen Turbellarien des Bodensees. Jahreshefte der Gesellschaft fur Naturkunde in Wurttemberg, 131, 163 - 181.","Schwank, P. (1981) Turbellarien, Oligochaeten und Archianneliden des Breitenbachs und anderer oberhessischer Mittelgebirgsbache. I. Lokalgeographische Verbreitung und die Verteilung der Arten in den einzelnen Gewassern in Abhangigkeit vom Substrat. Archiv fur Hydrobiologie, Supplement, 62, 1 - 85.","Schwank, P. (1985) Differentiation of the coenoses of helminthes and annelida in exposed lotic microhabitats in mountain streams. Archiv fur Hydrobiologie, 103, 535 - 543.","Heitkamp, U. (1982) Untersuchungen zur Biologie, Okologie und Systematik limnischer Turbellarien periodischer und perennierender Kleingewasser Sudniedersachsens. Archiv fur Hydrobiologie, Supplement, 64, 65 - 188.","Muller, D. & Faubel, A. (1993) The ' Turbellaria' of the River Elbe Estuary. A faunistic analysis of oligohaline and limnic areas. Archiv fur Hydrobiologie, Supplement, 75, 363 - 396.","Mack-Fira, V. (1970 b) The Turbellarian fauna of the Romanian littoral waters of the Black Sea and its annexes. In: Riser, N. W. & Morse, M. P. (Eds.), Biology of the Turbellaria. Libbie H. Hyman Memorial Volume, Mc-Graw-Hill Company, New York, pp. 248 - 290.","Kolasa, J. (1974) Badania nad wirkami (Turbellaria) zrodel ze szcegolnym uwzglednieniem okologic Poznania (The investigations on spring Turbellaria with a special regard to surroundings of Poznan). Badania Fizjograficzne nad Polska Zachodni q, 26, 1 - 31.","Korgina, E. M. (1999) Turbellaria fauna in reservoirs of the North-Dvina system. Zoologicheskii Zhurnal, 78, 1245 - 1247.","Korgina, E. M. (2002) Survey of Turbellaria fauna from the upper Volga River bassin (in Russian). Zoologicheskii Zhurnal, 81, 1019 - 1024.","Norena, C., Eitam, A. & Blaustein, L. (2008) \" Microturbellarian \" flatworms (Platyhelminthes) from freshwater pools: new species and records from Israel. Zootaxa, 1705, 1 - 20.","Ruebush, T. K. (1937) The genus Dalyellia in America. Zoologischer Anzeiger, 119, 237 - 256.","Szynal, E. (1933) Nowe gatunki i odmiany wirkow z rodzaju Dalyellia J. Flemming z pasma Czarnohorskiego. Sprawozdania Towarkzystwa Naukowego we Lwowie, 12, 209 - 211.","Gieysztor, M. & Szynal, E. (1939) Beitrage zur Kenntnis der Turbellarienfauna des Czarnohora-Gebirges (Ostkarpaten). Zoologica Poloniae, 3, 267 - 282."]}

Itaipusa biglandula n. sp. (Fig. 2) Locality. Santa Cruz Island, Bahia Academy, Station IX 5 g, upper layer of coarse-grained sand (type locality). Material. Several specimens studied alive. A total of 42 serially-sectioned animals, one of which is designated holotype (ZMUG 23231), 13 others designated paratypes (ZMUG 23232-23244). Voucher specimens deposited as ZMUG 23252-23279. Etymology. Species name refers to the presence of two symmetrical atrial glands. Glandula (Lat.): gland. Diagnosis. Species of Itaipusa Marcus, 1949, with two atrial glands symmetrically located beside the female duct; male system with a short, unarmed penis papilla; large bursa with resorptive part and muscular bursal stalk opening into female duct. Description. Live animals �� 1.3 mm long, caudally rounded, with two eyes. The syncytial epidermis is �� 6 ��m thick and shows a prominent basement membrane. It contains numerous apically-elongated, oviform, 2���4 ��m long rhabdites, which are absent in the head region, from the anterior tip to half the proboscis length. The animal is ciliated over the entire body (cilia �� 6 ��m long) with sensory bristles (�� 25 ��m long) surrounding the proboscis opening. The proboscis measures almost 1 / 5 of the body length and shows the characteristic features of a typical koinocystidid proboscis (see Brunet 1972; Karling 1980). It has a very strong Itaipusa - type proboscis juncture sphincter (see Karling 1980: p. 260). The pharynx is situated at about 40 %, and does not show any peculiarities in comparison with other species of Itaipusa or Koinocystididae in general (see Meixner (1925) and Karling (1954, 1980) for a detailed account). The oesophageal glands, clearly visible in sectioned material, are not distinguishable on live animals. A pharynx mouth sphincter could not be observed on sectioned specimens. Male and female gonads are paired. The oval testes lie dorso-laterally, caudally from the pharynx, extending to the distal part of the ovaries, which are situated at �� 75 %. The vitellaria extend from the mouth to the ovaries, the anterior part being situated dorso-laterally, whereas the posterior part lies more central and ventrally to the testes. The common genital pore, situated at �� 90 %, opens into the common genital atrium, which is lined with a high, nucleated epithelium and is surrounded by longitudinal muscles. Anteriorly it receives the uterus, and the male duct more dorsally. The female system opens into the genital atrium from the dorso-caudal side. The elongated, paired seminal vesicles are lined with a low, nucleated epithelium and surrounded by longitudinal muscles. Both vesicles fuse just before entering the prostate vesicle, forming the ejaculatory duct. This duct runs centrally through the prostate vesicle and is surrounded by eight to ten filiform prostate gland necks, called prostate ducts by Karling (1980). The prostate glands proper are very large, surrounding the seminal vesicles and containing one type of basophilic, coarse-grained secretion. The almost globular prostate vesicle bulges into the male genital atrium in a short, muscular penis papilla. The exact course of the ejaculatory duct could not be revealed, except for its distal part that opens into the penis papilla. This part of the ejaculatory duct is surrounded by circular muscles. The male atrium is lined with a low, anucleated epithelium and does not seem to be surrounded by a muscle layer. The ovoid ovaries have short oviducts, which join to form the female duct and are lined with a low, anucleated epithelium. On this bifurcation, a short vitelloduct enters the female duct. This female duct is lined with a low, nucleated epithelium and surrounded by weak, circular muscle fibres, forming a strong sphincter distally. Although no sperm could be observed in this duct, it probably acts as a seminal receptacle, indicated by the fact that it is swollen in all specimens. Instead of opening into the common genital atrium, it is connected to a very muscular bursal stalk, which enters the atrium dorso-caudally, together with two symmetrically-placed, glandular complexes with fine-grained eosinophilic secretion (Fig. 2 B: gl). Over its whole length this stalk is surrounded by circular muscles, which are extremely thick proximally, close to the bursal organ proper, forming two very large sphincters. The bursa acts as a sperm-resorbing organ (resorptive vesicle of Karling 1980). The bursa has a nucleated epithelium, which merges with the sperm-resorbing mass more proximally. The uterus is lined with a high, nucleated epithelium and surrounded by spirally-running muscle fibres. It opens into the common genital atrium close to the genital pore and is provided with two types of glands. The first type contains a fine-grained eosinophilic secretion and is situated near the proximal end, although the exact location of the opening into the uterus is unclear. More distally a coarse-grained basophilic gland type is present. These glands open into the uterus lumen half way along the organ. Discussion. See the general discussion on Itaipusa following the remarks on I. variodentata (Karling et al., 1972) Karling, 1978., Published as part of Reygel, Patrick C., Willems, Wim R. & Artois, Tom J., 2011, Koinocystididae and Gnathorhynchidae (Platyhelminthes: Rhabdocoela: Kalyptorhynchia) from the Galapagos, with the description of three new species, pp. 27-40 in Zootaxa 3096 on pages 30-31, DOI: 10.5281/zenodo.200746, {"references":["Marcus, E. (1949) Turbellaria Brasileiros (7). Boletins da Faculdade de Filosofia Ciencias e Letras, Universidade de Sao Paulo Zoologia, 14, 7 - 155.","Brunet, M. (1972) Koinocystididae de la region de Marseille (Turbellaria, Kalyptorhynchia). Zoologica Scripta, 1, 157 - 174.","Karling, T. G. (1980) Revision of Koinocystididae (Turbellaria). Zoologica Scripta, 9, 241 - 169.","Meixner, J. (1925) Beitrag zur Morphologie und zum System der Turbellaria-Rhabdocoela: 1. Die Kalyptorhynchia. Zeitschrift fur Morphologie und Okologie der Tiere, 3, 255 - 343.","Karling, T. G. (1954) Einige marine Vertreter der Kalyptorhynchien-Familie Koinocystididae. Arkiv for Zoologi, 7, 165 - 183.","Karling, T. G., Mack-Fira, V. & Dorjes, J. (1972) First report on marine microturbellarians from Hawaii. Zoologica Scripta, 1, 251 - 269.","Karling, T. G. (1978) Anatomy and systematics of marine turbellaria from Bermuda. Zoologica Scripta, 7, 225 - 248."]}

Typhloplaninae Luther, 1904 Strongylostoma elongatum Hofsten, 1907 (Fig. 2 F) New localities in Spain. Doñana National Park, Provincia de Huelva, Spain (36 ° 49 ’ 27 ”N, 6 ° 21 ’ 40 ”W). Llanos del Taraje near Ecomuseo Robledo de la Plancha: muddy temporal pond with Ranunculus aquatilis and sedges (25 /03/ 2008). Doñana National Park, Provincia de Huelva, Spain (37 °04’ 23 ”N, 6 ° 22 ’ 28 ”W). Laguna de la FAO: permanent water body with submersed vegetation (05/04/ 2008). Other localities in Spain. Central areas (Sierra de Guadarrama and river Tajo basin, see Gamo & Noreña- Janssen 1998). New locality outside Spain. Palearctic: Mol, Antwerp, Belgium (51 ° 13 ’06”N, 05° 10 ’ 49 ”E). Buitengoor: aquatic vegetation from a marsh in an open area (20 /08/ 2008). Known distribution. Widespread throughout the Palearctic: many localities in Europe, Western Russia, Siberia (see Luther 1963 for localities and references), Western Europe (UK: North Wales) (Young 1972 b, 1973), Central Europe (Germany: South Lower Saxony) (Heitkamp 1982), Eastern Europe (Romania: floodplain of the Danube, littoral freshwater lakes of the Black Sea) (Mack-Fira 1968; 1970 b), Western Russia (Urals, Northern Dvina River and upper Volga River) (Rogozin 1996; Korgina 1999, 2002) and the Middle East (Israel) (Noreña et al. 2008); Nearctic: Greenland (Steinböck 1932), USA (New York, Wisconsin) (Kolasa et al. 1987; Watermolen 2005), Canada (Ontario) (Gregory et al. 2000). Material. Studies on several live animals from the new localities in Spain of which three were whole mounted. Observations on one live specimen from Belgium. Remarks. Strongylostoma elongatum can easily be recognized from the other representatives of the taxon Strongylostoma Ørsted, 1844 by the construction of the copulatory organ. Spines are only present in the distal part of the ejaculatory duct, while other species have spines over the entire length of the ejaculatory duct (S. cirratum Beklemischew, 1922, S. dicorymbum Marcus, 1946 and S. radiatum Müller, 1774) or completely lack spines (S. simplex Meixner, 1915). In all live animals, the copulatory organ and the muscular copulatory bursa were clearly visible. However, the spines of the ejaculatory duct disappear when mounted with lactophenol. Although for S. gonocephalum (Silliman, 1884) Graff, 1911 and S. coecum (Sekera, 1906) Sekera, 1912 a detailed description of the copulatory organ is lacking, they can be easily distinguished from S. elongatum by the lack of eyes in S. coecum and the presence of “Grübchenflecken” (deepened oval spots beside and behind the eyes) and reticulated vitellaria in S. gonocephalum (see Graff 1913), features the specimens from Spain do not show. For a more detailed discussion on the taxon Strongylostoma, see the discussion of S. devleeschouweri n. sp.

Mesostoma lingua (Abildgaard, 1789) Graff, 1882 syn. Planaria lingua Abildgaard, 1789 syn. Planaria ehrenbergii Focke, 1836 syn. Mesostomum lingua Schmidt, 1848 syn. Turbella cyathus Diesing, 1862 syn. Turbella lingua Diesing, 1862 syn. Mesostoma cyathus Schmidt, 1858 syn. Mesostoma chromobactrum Braun, 1885 syn. Mesostoma cyanthus D��rner, 1902 syn. Mesostoma sigmoideum Plotnikow, 1905 New locality in Spain. Do��ana National Park, Provincia de Huelva, Spain (36 �� 57 ��� 28 ���N, 6 �� 26 ��� 59 ���W). Laguna del Sopeton near Casa del Puntal: large open pond with many filiform algae and zooplankton (mainly Daphnia sp.) (25 /03/ 2008). Other localities in Spain. Central areas (Sierra de Guadarrama and river Tajo basin, see Gamo & Nore��a- Janssen 1998); Alburquerque (Provincia de Badajoz, Extremadura) and C��ceres (Provincia de C��ceres, Extremadura) (Nore��a et al. 1999); Pla, Valencia (Provincia de Valencia, Comunidad Valenciana) and Almenara (Provincia de Castell��n, Comunidad Valenciana) (Gieysztor 1931). New localities outside Spain. Palearctic: D��partement du Var, Provence-Alpes-C��te d���Azur, France. Dry mud from a temporal pond provided by Dr. Alain Thi��ry (09/ 2007) and hatched at Hasselt University (Belgium) (10 / 2007). Nearctic: Cootes Paradise, Hamilton, Ontario, Canada (43 �� 16 ���01���N, 79 �� 55 ��� 54 ���W). Submersed and floating aquatic vegetation in a ditch adjacent to Spencer Creek (14 /05/ 2009). Known distribution. Widespread throughout the Palearctic: many localities in Europe, Western Russia, Siberia, Central Asia, Western Tibet and Japan (see Luther 1963 and Heitkamp & Schrade-Mock 1978 for localities and references), Western Europe (UK: West Midlands and North Wales; the Netherlands: Friesland) (Young 1970, 1972a, 1973), Central Europe (Germany: Thuringia, Lake Constance, Franconia, South Lower Saxony; Austria: Burgenland) (Kraus 1965; P��rner 1966; Rixen 1968; Bauchhenss 1971; Heitkamp 1981, 1982, 1988), Eastern Europe (Romania: Wallachian Plain, littoral freshwater lakes of the Black Sea, Danube Delta) (Mack-Fira 1968, 1970b), Western Russia (Yaroslavl Oblast, Urals, Northern Dvina River and upper Volga River) (Birstein 1991; Rogozin 1996; Korgina 1999, 2002; Kotikova 2001), Siberia and the Russian Far East (Rogozin 1996), North Africa (Algeria) (Gauthier 1929; Schrade 1974); Nearctic: Greenland (Steinb��ck 1932); Afrotropic: many localities in East Africa (Kenya, Tanzania and Uganda) (see Beauchamp 1953; Young 1976; Young & Young 1976); Neotropic: Argentina (Nore��a-Janssen 1995). Material. Many live animals and serially-sectioned specimens from the new locality in Spain. Studies on live animals from France and several sectioned specimens from Canada. Remarks. Adult specimens were highly variable in length (most between 2 and 5 mm) and were milky white to pink. Body shape is bluntly rounded anteriorly and somewhat bluntly pointed posteriorly. Eggs were present on both sides of the body. Internal organization as described by several authors (e.g. Luther 1963; Nore��a-Janssen & Faubel 1992). Mesostoma lingua (Abildgaard, 1789) Graff, 1882 was captured with a small plankton net pulled through algae and vegetation, and was very abundant (more than 50 individuals in three throws). It seems to be a widespread species (Palearctic, Nearctic, Neotropic, Afrotropic), although records from the Oriental, Australasian, Pacific and Antarctic regions are presently lacking (see Nore��a-Janssen & Faubel 1992; Nore��a-Janssen 1995)., Published as part of Steenkiste, Niels Van, Tessens, Bart, Krznaric, Kathleen & Artois, Tom, 2011, Dalytyphloplanida (Platyhelminthes: Rhabdocoela) from Andalusia, Spain, with the description of four new species, pp. 1-29 in Zootaxa 2791 on page 8, DOI: 10.5281/zenodo.201106, {"references":["Abildgaard, P. C. (1789) In: Muller, O. F. (Ed.), Zoologia Danica, seu animalium Daniae et Norvegiae rariorum ac minus notorum descriptiones et historia. Havniae, 3, pp. 75.","Graff, L. von (1882) Monographie der Turbellarien I. Rhabdocoelida. Text + Atlas, Leipzig, 442 pp., 20 t.","Focke, G. W. (1836) Planaria ehrenbergii. Annalen des Wiener Museums der Naturgeschichte, 1, 191 - 206.","Schmidt, O. (1848) Die rhabdocoelen Strudelwurmer (Turbellaria rhabdocoela) des sussen Wassers. Friedrich Mauke Verlag, Jena, 67 pp.","Diesing, K. M. (1862) Revision der Turbellarien, Rhabdocoelen. Sitzungsberichte der Akademie der Wissenschaften Wien, 45, 191 - 318.","Schmidt, O. (1858) Die Rhabdocoelen Strudelwurmer aus den Umgebungen von Krakau. Denkschriften der Mathematisch-Naturwissenschaftlichen Classe der kaiserliche Akademie der Wissenschaften, 15, 1 - 45.","Braun, M. (1885) Die Rhabdocoeliden Turbellarien Livlands. Ein Beitrag zur Anatomie, Systematik und geographischen Verbreitung dieser Tiere. Archiv fur die Naturkunde, Liv-, Ehst- und Kurlands Serie II, 10, 1 - 125.","Dorner, G. (1902) Darstellung der Turbellarienfauna der Binnengewasser Ostpreussens. Schriften der Physikalische-okonomischen Gesellschaft zu Konigsberg, 43, 1 - 58.","Plotnikow, W. (1905) Ueber einige rhabdocoele Turbellarien Sibiriens. Zoologische Jahrbucher - Abteilung fur Systematik, Okologie und Geographie der Tiere, 21, 479 - 490.","Norena, C., del Campo, A. & del Real, M. (1999) Taxonomy and morphology of limnic microturbellarians (Platyhelminthes) in Extremadura (Spain). Hydrobiologia, 397, 21 - 28.","Gieysztor, M. (1931) Contribution a la connaissance des Turbellaries Rhabdoceles (Turbellaria Rhabdocoela) d'Espagne. Bulletin de l'Academie Polonaise des Sciences et des Lettres, Classe des Sciences Mathematiques et Naturelles. Serie B: Sciences Naturelles (II), 1931, 125 - 153.","Luther, A. (1963) Die Turbellarien Ostfenoskandiens IV. Neorhabdocoela 2. Typhloplanoida: Typhloplanidae, Solenopharyngidae und Carcharodopharyngidae. Fauna Fennica, 16, 1 - 163.","Heitkamp, U. & Schrade-Mock, W. (1978) Speziationsprozesse bei Mesostoma lingua (Turbellaria Rhabdocoela). Acta Zoologica Fennica, 154, 47 - 57.","Young, J. O. (1970) British and Irish freshwater Microturbellaria: historical records, new records and a key for their identification. Archiv fur Hydrobiologie, 67, 210 - 241.","Young, J. O. (1972 a) The Turbellaria of some Friesland lakes with incidental records of Gasteropoda and Hirudinea. Zoologische Bijdragen, 13, 59 - 70.","Young, J. O. (1973) The occurrence of Microturbellaria in some British lakes of diverse chemical content. Archiv fur Hydrobiologie, 72, 202 - 224.","Kraus, H. (1965) Zur Turbellarienfauna des Seewinkels im Neusiedlerseegebiet. Wissenschaftliche Arbeiten aus dem Burgenland, 32, 60 - 115.","Porner, H. (1966) Die rhabdocoeliden Turbellarien der Gewasser von Jena und Umgebung. Limnologica, 4, 27 - 44.","Rixen, J. - U. (1968) Beitrag zur Kenntnis der Turbellarienfauna des Bodenseegebietes. Archiv fur Hydrobiologie, 64, 335 - 365.","Bauchhenss, J. (1971) Die Kleinturbellarien Frankens. Ein Beitrag zur Systematik und Okologie der Turbellaria excl. Tricladida in Suddeutschland. Internationale Revue der gesamten Hydrobiologie und Hydrographie, 56, 609 - 666.","Heitkamp, U. (1981) Die Turbellarienfauna des Seeburger Sees in Sudniedersachsen. Drosera, 81, 27 - 32.","Heitkamp, U. (1982) Untersuchungen zur Biologie, Okologie und Systematik limnischer Turbellarien periodischer und perennierender Kleingewasser Sudniedersachsens. Archiv fur Hydrobiologie, Supplement, 64, 65 - 188.","Heitkamp, U. (1988) Life-cycles of microturbellarians of pools and their strategies of adaptation to their habitats. Fortschritte der Zoologie, 36, 449 - 456.","Mack-Fira, V. (1968) Rhabdocoeliden aus dem Uberschwemmungsgebiet der Donau. Limnologische Berichte der X. Jubilaumstagung Donauforschung, Bulgarien, 10 - 20 Oktober, 1966, 251 - 258.","Mack-Fira, V. (1970 b) The Turbellarian fauna of the Romanian littoral waters of the Black Sea and its annexes. In: Riser, N. W. & Morse, M. P. (Eds.), Biology of the Turbellaria. Libbie H. Hyman Memorial Volume, Mc-Graw-Hill Company, New York, pp. 248 - 290.","Birstein, V. J. (1991) On the karyotypes of the Neorhabdocoela species and karyological evolution of Turbellaria. Genetica, 83, 107 - 120.","Rogozin, A. G. (1996) Turbellaria of Eastern Russia. Hydrobiological Journal, 32, 54 - 60.","Korgina, E. M. (1999) Turbellaria fauna in reservoirs of the North-Dvina system. Zoologicheskii Zhurnal, 78, 1245 - 1247.","Korgina, E. M. (2002) Survey of Turbellaria fauna from the upper Volga River bassin (in Russian). Zoologicheskii Zhurnal, 81, 1019 - 1024.","Kotikova, E. A. (2001) Catecholaminergic neurons in the nervous system of Neorhabdocoela (Turbellaria). Journal of Evolutionary Biochemistry and Physiology, 37, 427 - 433.","Gauthier, H. (1929) Recherches sur la faune des eaux continentales de l'Algerie et de la Tunisie. These Faculte des Sciences, Universite de Paris, 419 pp.","Schrade, W. (1974) Zur Vortpflanzungsbiologie verschiedener Populationen von Mesostoma lingua (Abildgaard, 1789) (Turbellaria, Neorhabdocoela) aus Europa und Afrika. Diplomarbeit der Mathematisch-Naturwissenschaftlichen Fakultat, Georg- August-Universitat Gottingen, 36 pp.","Steinbock, O. (1932) Die Turbellarien des arktischen Gebietes. Fauna Arctica, Jena, 6, 295 - 342.","Young, J. O. & Young, B. M. (1976) First records of eight species and new records of four species of freshwater microturbellarians from East Africa, with comments on modes of dispersal of the group. Zoologischer Anzeiger, 196, 93 - 108.","Norena-Janssen, C. & Faubel, A. (1992) Revision of the Subfamily Mesostominae, Rhabdocoela, Platyhelminthes. Mitteilungen Hamburg Zoologisches Museum Institut, 89, 7 - 47."]}

Reygel, Patrick C., Willems, Wim R., Artois, Tom J. (2011): Koinocystididae and Gnathorhynchidae (Platyhelminthes: Rhabdocoela: Kalyptorhynchia) from the Galapagos, with the description of three new species. Zootaxa 3096: 27-40, DOI: 10.5281/zenodo.200746

Promesostoma maculosum Ax, 1956 (Fig. 2 C) New locality. Rota, Provincia de C��diz, Spain (36 �� 38 ���09���N, 6 �� 23 ��� 50 ���W). Los Corrales: thin layer of very coarse sand in intertidal pools on a rocky cape (11 /04/ 2008). Known distribution. Northeast Atlantic: European Atlantic coast (Ax 1956; Ehlers & Sopott-Ehlers 1989); Bosporus and Sea of Marmara (Ax 1959); Mediterranean: Corsica and Sardinia (Willems 2005 and pers. comm. from Wim Willems). Material. Several individuals studied alive. Five whole mounts. Remarks. Animals are between 0.8��� 2 mm (= 1.2 mm; n = 4) long. This species can easily be distinguished from other species of Promesostoma Graff, 1882 because the stylet is curled over 360 �� in the middle (Fig. 2 C). The stylet of the Spanish specimens is between 364���396 ��m long (= 383 ��m; n = 5), which is longer than in specimens from other known localities (�� 250 ��m in the specimens from the French Atlantic coast, Ax 1956; �� 290 ��m in the specimens from Corsica, Willems 2005; no measurements given for the specimens from the Eastern Mediterranean, Ax 1959). Its new intermediate location in southern Spain suggests this animal is probably widespread throughout the Mediterranean and Atlantic coast of southwestern Europe., Published as part of Steenkiste, Niels Van, Tessens, Bart, Krznaric, Kathleen & Artois, Tom, 2011, Dalytyphloplanida (Platyhelminthes: Rhabdocoela) from Andalusia, Spain, with the description of four new species, pp. 1-29 in Zootaxa 2791 on page 4, DOI: 10.5281/zenodo.201106, {"references":["Ax, P. (1956) Turbellarien der Gattung Promesostoma von der franzosischen Atlantikkuste. Kieler Meeresforschungen, 12, 110 - 113.","Ehlers, U. & Sopott-Ehlers, B. (1989) Drei neue interstitielle Rhabdocoela (Platyhelminthes) von der franzosischen Atlantikkuste. Microfauna Marina, 5, 207 - 218.","Ax, P. (1959) Zur Systematik, Okologie und Tiergeographie der Turbellarienfauna in den ponto-kaspischen Brackwassermeeren. Zoologischer Jahrbucher - Abteilung fur Systematik, Geographie und Biologie der Tiere, 87, 43 - 184.","Graff, L. von (1882) Monographie der Turbellarien I. Rhabdocoelida. Text + Atlas, Leipzig, 442 pp., 20 t."]}

Protoplanella simplex Reisinger, 1924 (Fig. 3) New locality. La Puebla del Rio, Provincia de Sevilla, Spain (37 �� 13 ��� 39 ���N, 6 �� 10 ��� 52 ���W). Area recreativa Pozo de los Conejos along road A 3114 from La Puebla del Rio to Aznalcazar: mosses on bank of dried up temporal brook in open coniferous forest (21 /03/ 2008). Other localities in Spain. Central areas (Sierra de Guadarrama and river Tajo basin; see Gamo & Nore��a- Janssen 1998). Known distribution. Palearctic: Northern Europe (Finland) (Luther 1963) and Central Europe (Austria: Eastern Alps) (Reisinger 1924, 1954; An der Lan & Franz 1954; An der Lan 1963). Material. One drawing of a live animal and two serially-sectioned specimens. Remarks. As is also the case for other representatives of Protoplanellinae Reisinger, 1924, Protoplanella simplex Reisinger, 1924 is difficult to identify (for a recent discussion on Protoplanellinae, see Van Steenkiste et al. 2010). Not many accounts of this species are known from the literature (Reisinger 1924, 1954; An der Lan & Franz 1954; Luther 1963; Gamo & Nore��a-Janssen 1998). Therefore a more detailed description and discussion is provided here. At 0.4 mm long (measured on the serial sections), the animals from Andalusia are relatively small when compared to other populations (0.8���0.9 mm for Central and Northern European populations; see Reisinger 1924 and Luther 1963). The ciliated epidermis is cellular and its apical end is darkly stained. The first third of the body is filled with two bundles of massive rhabdite glands, almost entirely encompassing the brain. The rhabdites are oblong, but seem to be variable in shape. The proximal parts of the gland cells are clearly visible as basophilic cells containing packages of rhabdites. Only adenal rhabdites are present. The mouth is situated at about 50���55 %. The pharynx rosulatus is typical of Typhloplanidae and has a central position. Two separate nephridiopores open on the ventral body surface slightly caudally to the mouth. The gonopore lies at 70 %. The paired, globular testes lie laterally behind the pharynx, ventrally to the vitellaria. Between the testes, an oviform copulatory organ provided with circular muscles is present. Proximally it contains a great amount of sperm, while distally the faint contours of a muscular ejaculatory duct were visible. The copulatory organ enters the common genital atrium dorsally. Rostral to the copulatory organ, the common genital atrium enlarges significantly. This sack-like protrusion (bs in Fig. 3) is provided with well-developed, circular muscles, as is the common genital atrium. The female system is relatively simple. Paired vitellaria stretch dorsolaterally at both sides up to the frontal part of the pharynx. At the caudal end of the left vitellarium is an ovary, which is partly embedded in this vitellarium, thus forming an ovovitellarium. The oviduct merges with a spherical female bursa with a relatively thick epithelium. The female bursa contains remnants of (disintegrated) sperm. Both the epithelium of the oviduct and the proximal part of the female bursa contain a large number of cell nuclei. The female duct (ductus communis in Reisinger 1924) is surrounded by circular muscles and enters the common genital atrium caudally. Eosinophilic glands surround the oviduct, but their exact entry position could not be determined. An uterus is absent. Discussion. The specimens from Spain can be placed in the taxon Protoplanella Reisinger, 1924, because they have all diagnostic features of this taxon: adenal rhabdites in the rod tracks, a typical pharynx rosulatus, a muscular ejaculatory duct and the presence of an ovovitellarium. At present Protoplanella contains two species: P. s i m p l e x and P. macrorhabdiphora An der Lan, 1955. However, as stated by An der Lan (1955), the position of P. m a c - rorhabdiphora is highly questionable since the construction of the genital system was not clear. Therefore P. s i m - plex remains the only certain representative of Protoplanella. Protoplanella strongly resembles another monotypic taxon within the Protoplanellinae, i.e. Olisthanellinella Reisinger, 1924 (O. rotundula Reisinger, 1924), but the latter taxon has a separate ovary and vitellaria. Luther (1963) also refers to the position of the testes as being a valuable field character in discerning Protoplanella from Olisthanellinella, although this is not mentioned by Reisinger (1924). In the taxon Protoplanella the testes are situated behind the pharynx, while the testes of O. rotundula lie next to or in front of the pharynx. Despite their small size, the Spanish specimens can be placed within Protoplanella simplex because they share all diagnostic characters. In addition, Reisinger (1924) describes the female bursa as a seminal receptacle. We prefer to describe it as a female bursa because it is relatively thick-walled and contains disintegrated sperm. Many older authors denote the female duct in Typhloplanidae as a ductus communis (e.g. Graff 1882; Sekera 1912; Dorner 1902; Findenegg 1930; Luther 1963). In more recent taxonomic accounts on Typhloplanidae, the terms ductus communis (e.g. Gamo & Schwank 1987; M��ller & Faubel 1993; Nore��a et al. 1999), female common duct (e.g. Kolasa & Schwartz 1988), female duct (e.g. Artois et al. 2004; Willems et al. 2005) and female canal (e.g. Nore��a-Janssen 1995) are used to describe the distal part of the female genital system, while Nore��a and Faubel (1992) consider the female duct as the collective name for the germarium (ovary), oviduct, seminal receptacle and distal ductus communis in their review on the Mesostominae. We prefer to use the term female duct to avoid confusion with other ducts in the genital system and to stress its presence in the female system. Finally we would like to remark that the specimens were sampled in spring when the area regularly receives rainfall. During summer (June to September), this area is prone to long periods of drought, suggesting this species might be anhydrobiotic (see Van Steenkiste et al. 2010)., Published as part of Steenkiste, Niels Van, Tessens, Bart, Krznaric, Kathleen & Artois, Tom, 2011, Dalytyphloplanida (Platyhelminthes: Rhabdocoela) from Andalusia, Spain, with the description of four new species, pp. 1-29 in Zootaxa 2791 on pages 6-7, DOI: 10.5281/zenodo.201106, {"references":["Reisinger, E. (1924) Die terricolen Rhabdocoelen Steiermarks. Zoologischer Anzeiger, 59, 33 - 143.","Luther, A. (1963) Die Turbellarien Ostfenoskandiens IV. Neorhabdocoela 2. Typhloplanoida: Typhloplanidae, Solenopharyngidae und Carcharodopharyngidae. Fauna Fennica, 16, 1 - 163.","Reisinger, E. (1954) Edaphische Kleinturbellarien als bodenkundliche Leitformen. Sonderdruck aus Carinthia II, Mitteilungen des Naturwissenschaftlichen Vereines fur Karnten, 64, 106 - 123.","Van Steenkiste, N., Davison, P. & Artois, T. (2010) Bryoplana xerophila n. g. n. sp., a new limnoterrestrial microturbellarian (Platyhelminthes, Typhloplanidae, Protoplanellinae) from epilithic mosses, with notes on its ecology. Zoological Science, 27, 285 - 291.","Gamo, J. & Norena-Janssen, C. (1998) Old and new records of turbellarians from the central areas of Spain. Hydrobiologia, 383, 299 - 305.","Graff, L. von (1882) Monographie der Turbellarien I. Rhabdocoelida. Text + Atlas, Leipzig, 442 pp., 20 t.","Sekera, E. (1912) Monographie der Gruppe Olisthanellini. Sitzungsberichte der Konigliche Bohmischen Gesellschaft der Wissenschaften, Mathematisch-Naturwissenschaftliche Classe, 1911, 24, 1 - 91.","Dorner, G. (1902) Darstellung der Turbellarienfauna der Binnengewasser Ostpreussens. Schriften der Physikalische-okonomischen Gesellschaft zu Konigsberg, 43, 1 - 58.","Findenegg, I. (1930) Untersuchungen an einigen Arten der Familie Typhloplanidae. Zoologische Jahrbucher - Abteilung fur Systematik, Geographie und Biologie der Tiere, 59, 73 - 130.","Gamo, J. & Schwank, P. (1987) One new species of Castrada (Turbellaria Neorhabdocoela) and four new records of Microturbellarians in the Iberian Peninsula. Archiv fur Hydrobiologie, 110, 605 - 615.","Muller, D. & Faubel, A. (1993) The ' Turbellaria' of the River Elbe Estuary. A faunistic analysis of oligohaline and limnic areas. Archiv fur Hydrobiologie, Supplement, 75, 363 - 396.","Norena, C., del Campo, A. & del Real, M. (1999) Taxonomy and morphology of limnic microturbellarians (Platyhelminthes) in Extremadura (Spain). Hydrobiologia, 397, 21 - 28.","Kolasa, J. & Schwartz, S. S. (1988) Two new Mesostoma species (Turbellaria, Rhabdocoela) from Australia. Zoologica Scripta, 17, 329 - 335.","Norena-Janssen, C. & Faubel, A. (1992) Revision of the Subfamily Mesostominae, Rhabdocoela, Platyhelminthes. Mitteilungen Hamburg Zoologisches Museum Institut, 89, 7 - 47."]}

13 pages; International audience; The IPY sister-projects CAML and SCAR-MarBIN provided a timely opportunity, a strong collaborative framework and an appropriate momentum to attempt assessing the “Known, Unknown and Unknowable” of Antarctic marine biodiversity. To allow assessing the known biodiversity, SCAR-MarBIN “Register of Antarctic Marine Species (RAMS)” was compiled and published by a panel of 64 taxonomic experts. Thanks to this outstanding expertise mobilized for the first time, an accurate list of more than 8100 valid species was compiled and an up-to-date systematic classification comprising more than 16,800 taxon names was established. This taxonomic information is progressively and systematically completed by species occurrence data, provided by literature, taxonomic and biogeographic databases, new data from CAML and other cruises, and museum collections. RAMS primary role was to establish a benchmark of the present taxonomic knowledge of the Southern Ocean biodiversity, particularly important in the context of the growing realization of potential impacts of the global change on Antarctic ecosystems. This, in turn, allowed detecting gaps in knowledge, taxonomic treatment and coverage, and estimating the importance of the taxonomic impediment, as well as the needs for more complete and efficient taxonomic tools. A second, but not less important, role of RAMS was to contribute to the “taxonomic backbone” of the SCAR-MarBIN, OBIS and GBIF networks, to establish a dynamic information system on Antarctic marine biodiversity for the future. The unknown part of the Southern Ocean biodiversity was approached by pointing out what remains to be explored and described in terms of geographical locations and bathymetric zones, habitats, or size classes of organisms. The growing importance of cryptic species is stressed, as they are more and more often detected by molecular studies in several taxa. Relying on RAMS results and on some case studies of particular model groups, the question of the potential number of species that remains to be discovered in the Southern Ocean is discussed.In terms of taxonomic inputs to the census of Southern Ocean biodiversity, the current rate of progress in inventorying the Antarctic marine species as well as the state of taxonomic resources and capacity were assessed. Different ways of improving the taxonomic inputs are suggested.

Parainvenusta englarorum Curini-Galletti sp. nov. (Fig. 2) Holotype: One specimen sagittally-sectioned (SAM AHC 29915) Type locality: Port Lincoln, South Australia. Sleaford Bay, Wreck beach (34 �� 51 ��� 36.71 ���S; 135 �� 43 ��� 41.19 ���E), fine sand, Jan. 2001 Additional material: one specimen sagittally sectioned (paratype: SMNH type- 7950); four specimens sagittally sectioned (CZM 181-183); two specimens frontally-sectioned (CZM 184, 185); four whole mounts (CZM 186-189); two karyological slides (CZM 190, 191.). Sleaford Bay, Lone Pine beach (34 �� 52 ���01.45���S; 135 �� 42 ��� 44.98 ���E), medium-fine sand, Jan. 2001: three specimens sagittally-sectioned (CZM 192-194). Etymology: the species is dedicated to Giuseppe and Saturna Englaro, for their long and strenuous struggle for the respect and actuation of the wills of their daughter Eluana (1970���2009), in irreversible vegetative state for 17 years, giving an exemplary lesson of laicity, love, and faith in legality. Description. Animals slender; fixed mounts up to 6 mm long. Anterior end with few sensory bristles. Body entirely ciliated; cilia about 3 ��m long. Epithelium with insunk nuclei. With numerous adhesive papillae in the tail; a few are scattered along the length of the body. Different types of glands are present at the periphery of the body: i) small, intensely stained eosinophylic glands (g 1 in Fig. 2 C), about 5 ��m long, with the main body below the basal lamina, and whose necks pierce the overlaying epithelium; ii) numerous ovoid rhabdoids (Figs 2 A���C: r), 15���20 ��m long, particularly dense in the caudal region; iii) long paracnida, containing an eversible tube, distinctly granular at its proximal end. Two types of paracnida, differing in position and morphology, can be recognized. A few (6���10), very large (up to 60 ��m long) and nearly straight, are placed radially around the genital area, and in most specimens form a rosette around the genital opening (Figs 2 A, B: p 1). Others (20 ��� 30 ��m long), more numerous and more irregularly coiled, are distributed mostly in the caudal region (Figs 2 A, B: p 2), where they are intermingled with rhabdoid glands. The brain is encapsulated, and abuts anteriorly the statocyst, which is about 20 ��m across. The two neural cords originating ventrally from the brain are easily appreciable in sections of the anterior part of the body. Subepithelial musculature thin, formed by an external, circular and an inner longitudinal layer. Numerous dorsoventral fibres are present, regularly arranged along the length of body. The gut extends from the cephalic area to the tail region. Pharynx in the posterior 3 rd of body. It is tubular, up to 500 ��m long, and directed horizontally. It is provided with a thin layer of external longitudinal musculature and an inner, thicker, circular component. The pharynx is ciliated (cilia 2.5���3 ��m long) apart from the distal tip, where long pharyngeal glands, which extend considerably anterior to the pharynx, discharge. With a short (20���30 ��m long) oesophagous, lined with unciliated, nucleated epithelium. Pharyngeal pocket lined with unciliated, nucleated epithelium; mouth ciliated. Male genital system. With few testes (20���30), arranged in two irregular rows in front of the ovaries. The testes are placed laterally, abutting the vitellaria, and often intermingled with them. Copulatory organ consisting of a globular bulb, connected to two seminal vesicles. The seminal vesicles are lined by a thin, flat epithelium, and extend laterally and posteriorly from the bulb, into which they enter dorsally. The bulb is 45��� 50 ��m across, lined externally by a flat, intranucleated epithelium. Below the epithelium, a strong muscular lining, 10���12 ��m thick, is present. It consists of relatively few and very large muscle cells, arranged into an external longitudinal and an inner, thicker, circular layer. The bulb is posteriorly oriented, and is connected to the body by a relatively small, ventral area, crossed by muscular fibres which are connected to the body musculature. The bulb contains a cirrus, which originates from the fusion inside the bulb of the distalmost portions of the two seminal vesicles. No prostatic vesicle was observed, nor cell bodies that could be identified as prostatic glands. The cirrus is unarmed, long and very convoluted, so that its length is impossible to measure with any degree of confidence in sections. It is lined internally, at least in parts, by a basal lamina, without overlying epithelium, and it is surrounded by a thin coating of muscular cells, more noticeable distally. The cirrus opens ventrally into the atrium. The rest of the bulb appears filled with somewhat loose parenchymatic cells, with ���empty��� spaces among cells. Female genital system. Vitellaria at both sides of the body, in front of the pharynx. Two ovaries in front of the pharynx. Oviducts ciliated; they run posteriorly, and open independently at the two sides of a small bursa. This is nearly spherical, with a lumen about 10 ��m across, and, in most specimens, contains sperm. The bursa is lined by an unciliated cuboidal epithelium, and opens anteriorly into the dorsal wall of the atrium through a short, ciliated bursal canal, 10���15 ��m long, which receives the female glands. Posteriorly, the bursa is connected to a long (50���60 ��m in sections), Sshaped duct, surrounded by very strong circular muscles. The muscle ring closest to the bursa is the strongest, and may act as a sphincter. This duct is lined by an unciliated, nucleated epithelium, and opens into the posterior-most portion of the gut, thus forming a genito-intestinal connection. In most specimens, the posterior gut appears filled with sperm, suggesting the existence of a distinct resorbing bursa in this part of the intestine. The common atrium is narrow, lined with an unciliated epithelium. The genital pore is surrounded by a sphincter. Karyotype. The only plate suitable for study had n= 5, with Chrom I isobrachial, and the rest of chromosome pairs heterobrachial. The smallest chromosome pair was about half the size of Chrom I. Discussion. The combination of characters found in the new species is unique, and, although clearly attributable to the Coelogynoporidae for a combination of characters (see discussion above), could not be fit into any extant genus. Indeed, albeit biased as this may be by incomplete taxonomic sample of coeloegynoporid genera, the species occupies a basal, isolated position in the molecular tree (Figure 1). As recalled by the etymology, Parainvenusta englarorum gen. nov. sp. nov. superficially resembles species of Invenusta, which possess similar strikingly long paracnida, and have an unarmed copulatory organ. Two species of Invenusta are known: I. aestus Sopott-Ehlers, 1976 (type species) from the eastern Atlantic (Canary Islands and French Atlantic coast) and I. paracnida (Karling, 1966) from western U.S.A. (Bodega Bay, California, and S. Juan islands, Washington). Both species have long paracnida, spread all over the body, and a copulatory organ provided with a muscular penis papilla, with the two seminal vesicles external to the bulb. Both lack a bursa, and the oviducts enter a ciliated diverticulum of the atrium. However, the two species appear to differ to an extent that their congenerity may be questioned. Among the main differences, the paracnida of I. aestus have the eversible part provided with barbs, while they are granular basally (and thus similar to the new species) in I. paracnida. The pharynx is short and oriented vertically, and the copulatory organ is anteriorly oriented, in I. aestus, while the pharynx is tubular and horizontal and the copulatory organ vertical in I. paracnida. Furthermore, in I. paracnida a long, convoluted genito-intestinal duct is present, while this is absent in I. aestus (Karling, 1966, Sopott-Ehlers, 1976). The structure of the female genital system in I. paracnida ��� consisting of a diverticulum of the atrium which receives the oviducts, and a long, winding genitointestinal connection - is indeed comparable to that of the new species. However, in P. englarorum, the ciliated duct, here interpreted as a bursal canal, leads to a bursa which receives the outlets of the oviducts, and is histologically different from the rest of the female system. Furthermore, the copulatory organ is of the simplex type in Invenusta, i.e. it is formed by a single muscular wall which surrounds the last portion of the ejaculatory duct (Karling, 1956; Litvaitis et al., 1996). In contrast, in P. englarorum the cirrus bulb contains a (presumably) eversible cirrus, surrounded by a fluid matrix. The presence of two muscular walls, an outer and inner one, this latter corresponding to the last portion of the ejaculatory duct, fits the definition of duplex-type copulatory bulb (Karling, 1956). Finally, the position of P. englarorum and I. aestus in the molecular tree (Fig. 1) does not support a close phylogenetic relationship among the two taxa. Within the Coelogynoporidae, a duplex��� type copulatory organ is present in the genera Cirrifera Sopott, 1972, Vannuccia Marcus, 1948, and Stilivannuccia Faubel & Rohde, 1998. In these taxa, however, the cirrus is provided with numerous spines; and accessory stylets may be present. In the genus Cirrifera, the seminal vesicle is entirely extracapsular, and a prostatic vesicle is present. Furthermore, species of Cirrifera have a vertically oriented pharynx, and lack a bursa and true paracnida (Jouk et al., 2007). In Vannuccia and Stilivannuccia, the seminal vesicle is anterior to the copulatory bulb, an intra-bulb prostatic vesicle is generally present, as well as a long female duct leading to the bursa. A cirrus is also present in Macroatrium setosum Riser, 1981 from N.W. Atlantic (New England); although its morphology is not known in details, it is spiny, broad, and cup-shaped, and thus very different from that of the new species. M. setosum lacks paracnida, and is provided with a comparatively very large atrium and a seminal bursa roughly of the same size as the atrium (Riser, 1981). Similarly to Parainvenusta englarorum, Pseudovannuccia hirutai (Tajika, 1981) is characterized by an unarmed copulatory organ. However, in this species the copulatory organ is of the simplex type (Faubel & Rohde, 1998), with a highly developed, strongly muscular penis papilla. Furthermore, the seminal vesicle is entirely within the copulatory bulb and anterior to the gonopore (Tajika, 1981). Given the morphological distinctiveness of the new species, its inclusion in any of the genera above would render that genus exceedingly heterogenous; and a new genus is thus proposed for it. FIGURE 2. Parainvenusta englarorum nov. sp. nov. gen. A: general appearance; B: Postpharyngeal genital organs, based on observations on living squeezed specimens and frontal sections; C: sagittal reconstruction of the postpharyngeal genital organs; D,E: genital area from frontal (D) and sagittal (E) sections. Scale bar: 25 ��m. Abbreviations: a: atrium; b: bursa; bc: bursal canal; br: brain; ci: cirrus; co: copulatory organ; fg: female glands; g 1: gland; gic: genito-intestinal connection; gl: gut lumen; gp: genital pore; mc: muscular lining of the cirrus bulb; mr: muscle ring; od: oviduct; ov: ovary; p 1: paracnida (genital area); p 2: paracnida (caudal area); ph: pharynx; r: rhabdoid gland; st: statocyst; sv: seminal vesicle; t: testis; vi: vitellaria., Published as part of Curini-Galletti, Marco, Webster, Bonnie L., Huyse, Tine, Casu, Marco, Schockaert, Ernest R., Artois, Tom J. & Littlewood, Timothy J., 2010, New insights on the phylogenetic relationships of the Proseriata (Platyhelminthes), with proposal of a new genus of the family Coelogynoporidae, pp. 1-18 in Zootaxa 2537 on pages 15-18, DOI: 10.5281/zenodo.196653

Genus Parainvenusta Curini-Galletti gen. nov. Diagnosis: Coelogynoporidae with long paracnida surrounding the genital pore and in the tail. Copulatory organ of the duplex type, containing a convoluted unarmed cirrus. With bursa, and long, muscular genito-intestinal connection. Etymology: The genus name is coined after the genus Invenusta Sopott-Ehlers, 1976, and reflects the superficial similarity between the two taxa., Published as part of Curini-Galletti, Marco, Webster, Bonnie L., Huyse, Tine, Casu, Marco, Schockaert, Ernest R., Artois, Tom J. & Littlewood, Timothy J., 2010, New insights on the phylogenetic relationships of the Proseriata (Platyhelminthes), with proposal of a new genus of the family Coelogynoporidae, pp. 1-18 in Zootaxa 2537 on page 15, DOI: 10.5281/zenodo.196653

MEIDIAMIDAE, NEW FAMILY Diagnosis: Lithophoran Proseriata with an encapsulated brain, a precerebral gut diverticle, intraepidermal nuclei, and with the epidermis completely ciliated. Ovaries in front of the vitellaria, anterior of and close to the pharynx; a long female duct, the oviducts joining before the male copulatory organ, and with the female pore behind it (digonoporid condition). With a genito-intestinal connection close to the female pore, leading to a resorbing bursa incorporated in the gut. Testes: in front of the ovaries. Copulatory organ directed forwards, with a stylet and atrial needles, only needles, or only a stylet. One or a pair of seminal vesicles behind the copulatory organ. Accessory glandular organ, associated with the male atrium, present or not. Pharynx globular and directed ventrally. Type genus: Meidiama Marcus, 1946., Published as part of Schockaert, Ernest R., Curini-Galletti, Marco, Ridder, Wouter De, Volonterio, Odile & Artois, Tom, 2009, A new family of lithophoran Proseriata (Platyhelminthes), with the description of seven new species from the Indo-Pacific and South America, and the proposal of three new genera, pp. 759-773 in Zoological Journal of the Linnean Society 155 (4) on page 760, DOI: 10.1111/j.1096-3642.2008.00463.x, http://zenodo.org/record/4635038, {"references":["Marcus E. 1946. Sobre Turbellaria Brasilieros. Boletins da Faculdade de Filosofia, Ciencias e Letras, Universidade de Sao Paulo (Zoologia) 11: 5 - 253 + 31 plates."]}

MEIDIAMA MARCUS, 1946 Diagnosis (emended after Martens & Curini-Galletti, 1993): Filiform Meidiamidae with the prostate vesicle curved over about 180°, and with the proximal pole directed forwards, where the paired seminal vesicles enter; the distal pole, where the stylet is attached, is also directed forwards. The stylet is directed forwards and accompanied by the atrial needles. Accessory glandular organ absent. Genito-intestinal duct leading backwards from the female pore to a resorbing bursa in the gut. Female duct with a prepenial vagina, and functioning as a (prepenial) copulatory bursa. Type species: Meidiama lutheri Marcus, 1946. There are three species that are very similar, except for the hard parts of the copulatory organ and the number of testes. They are described together, mainly based on material of Meidiama uruguayensis sp. nov., Published as part of Schockaert, Ernest R., Curini-Galletti, Marco, Ridder, Wouter De, Volonterio, Odile & Artois, Tom, 2009, A new family of lithophoran Proseriata (Platyhelminthes), with the description of seven new species from the Indo-Pacific and South America, and the proposal of three new genera, pp. 759-773 in Zoological Journal of the Linnean Society 155 (4) on page 760, DOI: 10.1111/j.1096-3642.2008.00463.x, {"references":["Marcus E. 1946. Sobre Turbellaria Brasilieros. Boletins da Faculdade de Filosofia, Ciencias e Letras, Universidade de Sao Paulo (Zoologia) 11: 5 - 253 + 31 plates.","Martens PM, Curini-Galletti MC. 1993. Taxonomy and phylogeny of the Archimonocelididae Meixner, 1938 (Platyhelminthes, Proseriata). Bijdragen tot de Dierkunde 63: 65 - 102."]}

DREUXIOLA PHILLIPI SP. NOV. Diagnosis: Species of Dreuxiola with about 25 testes, a very long and coiled stylet, about 250-Mm long, and two groups of four needles, each 35–37-Mm long. The vagina ends with a sclerotized (‘cuticular’) tube. Occurrence: Port aux Français, Kerguelen (Territoire Australe Français), on the flat beach east of the port; fine sand in the mid-littoral, dominated by nematodes. Material studied: Observations were made on the living animals and two whole mounts (one of them indicated as the holotype, SMNH 7353, the other indicated as a paratype UH 381); four series of sections, from which only two contain relevant information (UH 382–385). Etymology: Genus and species are named in honour of Prof. Philippe Dreux (Université Pierre et Marie Curie, Paris): entomologist and noted authority on the wingless Curculionidae (Coleoptera) of the French Austral Territories. Description: The animals are very long and slender, 3–4-mm long, with some anterior sensory bristles. Adhesive papillae were not seen in the whole mounts, nor were they seen in the sections. The brain is encapsulated, and there is a clear extension of the gut over the brain. The pharynx is directed ventrally, is slightly lobate, and is placed at two-thirds of the body length (Fig. 5). The epidermis is 1-Mm-thick ventrally and 1.5-Mm-thick dorsally; cilia are 2-Mm long. The ovaries are just in front of the pharynx, and most vitellarian follicles are behind the pharynx, extending over about one-third of the post-pharyngeal body part. Behind the last follicle, the two ovovitelloducts join into the common female duct, which looks very muscular and swollen in living animals, is filled with sperm, and clearly functions as a copulatory bursa. The vagina opens roughly in its middle, with a little sclerotized tube that is about 50-Mm long (Figs 6, 7). In the sections the vaginal duct appears as a narrow tube with a strongly muscular wall, surrounded by loose tissue that is also surrounded by some longitudinal muscles. In one of the sectioned animals this part is highly swollen, forming a vesicle that is also seen in the living animal and in the whole mounts (Fig. 6). Further backwards, the female duct narrows towards the female pore that is found at three-quarters of the postpharyngeal body part. From the female pore the genito-intestinal duct departs towards the resorbing bursa. The male system consists of about 25 testes in a row, extending from some distance behind the brain down to the level of the ovaries (Fig. 5). The copulatory organ lies between the female pore and the vagina, and has an astonishing construction (Figs 6– 9). The prostate vesicle has the proximal pole directed forwards, where the paired seminal vesicles enter, and the distal pole is directed backwards; distally, the prostate vesicle tapers, and recurves by almost 180°. The stylet starts with a bent proximal end, so that the stylet becomes directed forwards. The seminal vesicles lie next to the prostate vesicle and join each other in a short seminal duct that can be followed in the prostate vesicle. Here, its epithelium forms the prostate glands, of which the cell bodies with nuclei are outside the vesicle, and some nuclei are inside the bulb. The stylet is very narrow and very long. It makes a loop and enters the expanded male atrium. The proximal part of the atrium is swollen and contains a net-like glandular tissue surrounded by a thin muscle layer. Two groups of needles seem attached to this accessory glandular bulb. The stylet enters the male atrium roughly in the middle of this glandular bulb. The stylet is about 250-Mm long in the two whole mounts; the needles are 40–50-Mm long. These needles seem to be very slightly sclerotized, and are rather difficult to discern in whole mounts. Nevertheless, it could be observed that the needles are arranged symmetrically in two groups, each consisting of a shorter, curved needle at the outside, and a thicker, straight needle in the middle (both about 40-Mm long), and with two slender and moderately curved needles of about 50-Mm long in between (measurements from the two whole mounts)., Published as part of Schockaert, Ernest R., Curini-Galletti, Marco, Ridder, Wouter De, Volonterio, Odile & Artois, Tom, 2009, A new family of lithophoran Proseriata (Platyhelminthes), with the description of seven new species from the Indo-Pacific and South America, and the proposal of three new genera, pp. 759-773 in Zoological Journal of the Linnean Society 155 (4) on page 764, DOI: 10.1111/j.1096-3642.2008.00463.x, http://zenodo.org/record/4635038

MEIDIAMA SCHOCKAERTI MARTENS & CURINI- GALLETTI, 1993 Meidiama schockaerti: species of Meidiama with a straight stylet of about 65-Mm long, accompanied by 18–20 needles of 60 Mm, without hook; 9–10 testes in a row. Meidiama schockaerti: Pingüinera beach (Seno Otway), Chili (Magellan Province); coarse sand and gravel (not Punta Arenas, Argentina, as mentioned in the original description of Martens & Curini-Galletti 1993). Meidiama schockaerti: holotype (SMNH 7351; whole mount) Description: The animals are very long and slender: adults of M. lutheri are around 4-mm long; adults of M. schockaerti are 2–3-mm long and adults of M. uruguyaensis are around 6-mm long (all measured on the whole mounts), with some anterior sensory bristles. Adhesive papillae were not seen in the whole mounts, nor in the sections, but are present in the caudal region of M. lutheri, according to Marcus (1946). The brain is encapsulated, and there is a clear extension of the gut over the brain. The pharynx is directed ventrally, is slightly lobate, and is roughly in the middle of the body (Fig. 1). The epidermis is 1.5–2-Mm thick in M. lutheri, and the cilia are 3-Mm long dorsally and 4-Mm long ventrally; in M. uruguayensis the epidermis is 1–1.5-Mm thick, and the cilia are 2 and 3-Mm long, respectively. The ovaries are just in front of the pharynx, and the vitellarian follicles are all behind the pharynx, extending over around two-thirds of the postpharyngeal body part. Behind the last, most posterior follicle, the two ovovitelloducts join to form the common female duct. Slightly more posteriorly, this duct enlarges to form the copulatory bursa, in which a short vagina opens (Figs 1, 2). The female duct continues over a considerable distance (about 0.25 mm) to reach the female pore. From here departs a short genito-intestinal duct, which opens into a large resorbing bursa in the intestine. A connection with the gut is not seen, although some clusters of sperm are observed in the gut at the level of, and even anterior to, the copulatory organ. Very large cement glands run to the female pore, with the gland bodies lying mainly in the most caudal body part. The whole female duct is lined by a rather dense and nucleated epithelium, and is surrounded by spiral muscles. The epithelium is slightly higher in the copulatory bursa and in the most anterior part of the female duct. The muscle layer around the copulatory bursa is also slightly stronger than on the rest of the duct. The epithelium of the ovovitelloducts is very thin and sinuous, and no evidence of a resorbing function was seen. There are about 50 testes in M. uruguayensis (close to 100 in M. lutheri, according to Marcus 1946: fig. 120), roughly arranged in two rows, and with the first testis found at one-third of the prepharyngeal region, and with the last testes just in front of the ovaries. In M. schockaerti there are only 9–10 testes in a row. The copulatory organ, just in front of the female pore, is directed forwards. It consists of a pair of spherical seminal vesicles, from which long narrow ducts depart (Fig. 3). These ducts join to form a single seminal duct, which enters the prostate vesicle at its proximal pole. The seminal vesicles and the ducts are all surrounded by a strong spiral muscle layer. The prostate vesicle tapers anteriorly, where the stylet is attached, and is recurved over 180°, with both proximal and distal poles directed forwards. The seminal duct can clearly be seen in the centre of the vesicle, with its epithelium forming the prostate glands, the nucleated gland bodies of which are outside and inside the vesicle. In the large male atrium, the curved stylet and the atrial needles are found. The needles are situated in the distal half of the atrium, and are arranged in a half-open girdle, closed at the dorsal side (above the stylet), and open at the ventral side. The prostate vesicle is surrounded by very strong, spirally arranged muscles, which continue over the male atrium, and seem to be attached to the needles. A moderately strong sphincter surrounds the male pore. In both individuals of M. lutheri, the curved stylet is about 60-Mm long, the needles are 28–30-Mm long, and are also slightly curved. The funnel-like proximal end of the stylet has an opening of 7–8 Mm in diameter, with a strongly thickened wall, whereas the stylet diameter tapers from 5 Mm proximally to 2 Mm distally. The curvature of the very distal end is stronger than in the middle of the stylet, making a precise measurement difficult, as the entire length of the stylets in the whole mounts cannot be seen in the same plane. The terminal opening is oblique and tapering proximally. We counted nine needles, whereas Martens & Curini-Galletti (1993) counted ten, and Marcus (1946) mentions 12. Needles lying above each other are indeed often difficult to discern. Each needle ends in a slender ‘hook’, about one-third of the total length of the needle in the shortest needles, and about one-quarter of the total length in the longest needles. In M. uruguayensis the stylet is also curved, and is about 90-Mm long in the holotype. At the distal opening it bears a variably ornamented ‘wing’ (Fig. 4, inset). The obliquely-placed proximal opening, also with a strongly thickened wall, has a diameter of 20 Mm, and the stylet has a diameter of slightly less than 5 Mm distally. There are about 18 needles, which are 31–37-Mm long, with the shortest needle located in the middle of the circle. The terminal ‘hooks’ have a strongly curved tip, and are a little less than between one-fifth and one-quarter of the total length of the needles. The length of the stylet varies from 76 to 90 Mm (n = 7, mean = 84 Mm); the shortest needles are 26–46-Mm long (n = 6, mean = 32 Mm), and the longest needles are 35–69-Mm long (n = 6, mean = 44 Mm). The individuals with the longest stylet also have the largest needles. The copulatory organ of M. schockaerti deviates in a number of aspects from that of the other two species. The stylet is straight, close to 65-Mm long, and gradually narrows from 10-Mm wide at the proximal opening (without obvious thickening) to about 3-Mm wide distally. The needles are about 60-Mm long, and are without a terminal ‘hook’. We counted about 18 needles, whereas Martens & Curini-Galletti (1993) depicted 21 needles in a regular arrangement around the stylet. We have the strong impression that the needles are concentrated at one side of the stylet, as in the other species of Meidiama., Published as part of Schockaert, Ernest R., Curini-Galletti, Marco, Ridder, Wouter De, Volonterio, Odile & Artois, Tom, 2009, A new family of lithophoran Proseriata (Platyhelminthes), with the description of seven new species from the Indo-Pacific and South America, and the proposal of three new genera, pp. 759-773 in Zoological Journal of the Linnean Society 155 (4) on pages 760-763, DOI: 10.1111/j.1096-3642.2008.00463.x, http://zenodo.org/record/4635038, {"references":["Martens PM, Curini-Galletti MC. 1993. Taxonomy and phylogeny of the Archimonocelididae Meixner, 1938 (Platyhelminthes, Proseriata). Bijdragen tot de Dierkunde 63: 65 - 102.","Marcus E. 1946. Sobre Turbellaria Brasilieros. Boletins da Faculdade de Filosofia, Ciencias e Letras, Universidade de Sao Paulo (Zoologia) 11: 5 - 253 + 31 plates."]}

DREUXIOLA GEN. NOV. Diagnosis: Filiform Meidiamidae with many testes. The prostate vesicle has the proximal pole directed forwards, where the paired seminal vesicles enter. The distal pole is directed backwards, but at its end, where the stylet is attached, it turns sharply forwards, so that the stylet is directed forwards. It enters the male atrium next to the atrial needles. These needles are surrounded by a glandular epithelium with its own muscular envelope. Female duct with a prepenial vagina, functioning as a copulatory bursa. Genito-intestinal duct near the female pore leading to a resorbing bursa. Type species: Dreuxiola philippi sp. nov.

YORKNIA GEN. NOV. Diagnosis: Elongated Meidiamidae with many testes. Copulatory organ without atrial needles, and without accessory glandular organ. Prepenial copulatory bursa. Type species: Yorknia aprostatica sp. nov., Published as part of Schockaert, Ernest R., Curini-Galletti, Marco, Ridder, Wouter De, Volonterio, Odile & Artois, Tom, 2009, A new family of lithophoran Proseriata (Platyhelminthes), with the description of seven new species from the Indo-Pacific and South America, and the proposal of three new genera, pp. 759-773 in Zoological Journal of the Linnean Society 155 (4) on page 765, DOI: 10.1111/j.1096-3642.2008.00463.x, http://zenodo.org/record/4635038

SERRULA GEN. NOV. Diagnosis: Meidiamidae with a single pair of testes and the pharynx in the anterior part of the body. Copulatory organ with a pair of short atrial needles sitting on a muscular base. Without stylet and accessory glandular organ. Seminal vesicles paired or single. With or without prepenial vagina. Genitointestinal connection absent? Type species: Serrula byronensis sp. nov. There are four species that are very similar, and these are described together., Published as part of Schockaert, Ernest R., Curini-Galletti, Marco, Ridder, Wouter De, Volonterio, Odile & Artois, Tom, 2009, A new family of lithophoran Proseriata (Platyhelminthes), with the description of seven new species from the Indo-Pacific and South America, and the proposal of three new genera, pp. 759-773 in Zoological Journal of the Linnean Society 155 (4) on page 766, DOI: 10.1111/j.1096-3642.2008.00463.x

YORKNIA APROSTATICA SP. NOV. Diagnosis: Species of Yorknia with 15 testes in a row, without either prostate glands or vesicle, and with an almost straight stylet of about 80-Mm long, with a proximal ‘cap’ of 30–40 Mm in diameter, and with a single large seminal vesicle. Female pore only slightly behind the male pore; prepenial copulatory bursa with two vaginas. Occurrence: Cairns, Australia (Queensland), at Yorkney’s Knob; intertidal in fine to medium-fine sand (type locality) (October 1993). Material studied: A whole mount, designated as the holotype, (QM G 230107). A second whole mount and six sectioned animals (UH 386 and UH 387–392). Etymology: The genus name is derived from the locality where the species was found; the species epithet is derived from the most striking character, namely the absence of prostate glands. Description: The animals are long and slender, 3–4-mm long, with some anterior sensory bristles. Adhesive papillae were not seen in the whole mounts, nor were they seen in the sections. The brain is encapsulated, and there is a clear extension of the gut over the brain. The pharynx is directed ventrally, is slightly lobate, and is located at between two-thirds and three-quarters of the body (Fig. 10A). The epidermis is 1.5-Mm thick, with 3-Mm-long cilia. The ovaries are just in front of the pharynx, and all vitellarian follicles are behind the pharynx, extending to the middle of the post-pharyngeal body part. Behind the last follicle the two ovovitelloducts join into the common female duct, which is swollen in the living animal, and clearly functions as a copulatory bursa. At about its middle, two vaginal pores can be seen (Fig. 10B). In the sections (Fig. 11), the two vaginas depart as a wide funnel from the dorsallysituated copulatory bursa. The female duct narrows towards the female pore, where the duct is enlarged again, and continues backwards as a genito-intestinal duct communicating with a large resorbing bursa. The epithelium covering the female duct is ciliated. This epithelium is very low in the copulatory bursa, in the vaginas, and at the dorsal side of the swollen part at the pore, and is extremely thin in the genitointestinal duct, where it is devoid of cilia. At their very end, the ovovitelloducts show aspects that suggest some resorbing function, but no degenerating sperm was observed. The cement glands, which open at the female pore, are very large and are found in the whole posterior part of the animal. The copulatory organ is provided with an almost straight stylet, lying in a tubiform, narrow male atrium that enlarges proximally to a narrow space, which receives at its ventral side the wide opening of the seminal vesicle. Dorsally, this proximal space is covered by a sclerotized ‘cap’, which has a fan-like muscle, with its wider side attached to the cap, and its narrower side attached to the stylet (see also Fig. 12). The seminal vesicle is extremely large, occupying almost the whole postpenial part of the animal. One of the most striking characters of this species is the complete absence of any prostate glands (and vesicle). The stylet (Fig. 12) is about 80-Mm long, with an almost constant diameter of 8–10 Mm; the ‘cap’ is 45-Mm long in the holotype, and is 30-Mm long in the paratype. The fan-like muscle is clearly visible in the whole mount., Published as part of Schockaert, Ernest R., Curini-Galletti, Marco, Ridder, Wouter De, Volonterio, Odile & Artois, Tom, 2009, A new family of lithophoran Proseriata (Platyhelminthes), with the description of seven new species from the Indo-Pacific and South America, and the proposal of three new genera, pp. 759-773 in Zoological Journal of the Linnean Society 155 (4) on pages 765-766, DOI: 10.1111/j.1096-3642.2008.00463.x, http://zenodo.org/record/4635038

SERRULA BYRONENSIS SP. NOV. Diagnoses: Serrula byronensis: species of Serrula with an unpaired seminal vesicle, a prepenial vagina, and a copulatory bursa. The needles are pointed: 14-Mm long, and 5–6-Mm wide at the base. The precerebral diverticle ends at the statocyst. Occurrence: Serrula byronensis: Byron Bay, Australia (New South Wales); exposed intertidal at Tallum Beach, mid-fine sand (October 1993)., Published as part of Schockaert, Ernest R., Curini-Galletti, Marco, Ridder, Wouter De, Volonterio, Odile & Artois, Tom, 2009, A new family of lithophoran Proseriata (Platyhelminthes), with the description of seven new species from the Indo-Pacific and South America, and the proposal of three new genera, pp. 759-773 in Zoological Journal of the Linnean Society 155 (4) on page 767, DOI: 10.1111/j.1096-3642.2008.00463.x, http://zenodo.org/record/4635038

MEIDIAMA MARCUS, 1946 Diagnosis (emended after Martens & Curini-Galletti, 1993): Filiform Meidiamidae with the prostate vesicle curved over about 180°, and with the proximal pole directed forwards, where the paired seminal vesicles enter; the distal pole, where the stylet is attached, is also directed forwards. The stylet is directed forwards and accompanied by the atrial needles. Accessory glandular organ absent. Genito-intestinal duct leading backwards from the female pore to a resorbing bursa in the gut. Female duct with a prepenial vagina, and functioning as a (prepenial) copulatory bursa. Type species: Meidiama lutheri Marcus, 1946. There are three species that are very similar, except for the hard parts of the copulatory organ and the number of testes. They are described together, mainly based on material of Meidiama uruguayensis sp. nov., Published as part of Schockaert, Ernest R., Curini-Galletti, Marco, Ridder, Wouter De, Volonterio, Odile & Artois, Tom, 2009, A new family of lithophoran Proseriata (Platyhelminthes), with the description of seven new species from the Indo-Pacific and South America, and the proposal of three new genera, pp. 759-773 in Zoological Journal of the Linnean Society 155 (4) on page 760, DOI: 10.1111/j.1096-3642.2008.00463.x, http://zenodo.org/record/4635038, {"references":["Marcus E. 1946. Sobre Turbellaria Brasilieros. Boletins da Faculdade de Filosofia, Ciencias e Letras, Universidade de Sao Paulo (Zoologia) 11: 5 - 253 + 31 plates.","Martens PM, Curini-Galletti MC. 1993. Taxonomy and phylogeny of the Archimonocelididae Meixner, 1938 (Platyhelminthes, Proseriata). Bijdragen tot de Dierkunde 63: 65 - 102."]}

SERRULA ACUTA SP. NOV. Serrula acuta: species of Serrula with a single seminal vesicle?; slender pointed needles that are 25-Mm long, and are 6-Mm wide at the base. No data on the living animal. Serrula acuta: same locality as S. maxillaria. Material studied: Drawings from the living animals, except for S. acuta. One whole mount of each species (designated as holotypes, QM G 230108–230111). Sections of one individual of S. byronensis of very poor quality, and without relevant information (except the epidermis) (UH 393). Etymology: The genus name refers to the serrate end of the needles in two of the species (Latin serrula: little saw). The species epithet of S. byronensis refers to the place where it has been found; that of S. concharum refers to the co-occurrence with many shells (Latin concha: shell); the needles of S. maxillaria show some resemblance to the maxillae of crustaceans; the needles of S. acuta are very slender and pointed (Latin acuta: pointed). Description: These four species are described from only one living individual of each species, and from the whole mounts. Therefore, our knowledge of a number of important characters is lacking. Nevertheless, we consider it worthwhile to describe them, hoping that more abundant material may be found in the future. The four species are relatively small: only about 1-mm long. They have the usual anterior sensory bristles, but also have long bristles at the caudal end. Serrula byron also has prominent adhesive papillae (Figs 13, 14). The precerebral gut diverticle reaches far in front of the statocyst in S. concharum, whereas it ends roughly above the statocyst in S. byronensis and S. maxillaria (and is unknown in S. acuta). Cnidocysts were seen in the anterior part of the gut in S. maxillaria. The globular and ventrally directed pharynx is placed at the first quarter of the body; the ovaries, located anterior to the pharynx, are preceded by a single pair of testes. All vitellarian follicles are behind the pharynx, and the posteriormost follicles are found in front of the copulatory bursa in S. byronensis, and in front of the copulatory organ in the other species. The female pore is located at some distance behind the seminal vesicle (Fig. 14). The copulatory organ is directed forwards, with a small prostate vesicle on which the two needles are attached. Serrula concharum has a pair of seminal vesicles; the other species have an unpaired seminal vesicle. Only in S. byron has a prepenial copulatory bursa been observed, with a vagina just in front of the copulatory organ. We could not determine whether the vagina and the male pore are combined or not. As far as the whole mount reveals, S. acuta has a single seminal vesicle, whereas a copulatory bursa is absent. Without sections, it cannot be said if a genitointestinal connection or a resorbing bursa is present. The hard parts of the copulatory organ (Fig. 15) consist of two spines that we interpret as the equivalent of the needles in the male atrium of the other representatives of Meidiamidae. Except in S. acuta, each of the two needles sits on a base, evidently formed by two muscles that ‘flank’ the prostate vesicle at either side. Because of the lack of sections, the hypothesis that these bases are muscles is yet to be confirmed. The form and size of the needles are given in the diagnoses., Published as part of Schockaert, Ernest R., Curini-Galletti, Marco, Ridder, Wouter De, Volonterio, Odile & Artois, Tom, 2009, A new family of lithophoran Proseriata (Platyhelminthes), with the description of seven new species from the Indo-Pacific and South America, and the proposal of three new genera, pp. 759-773 in Zoological Journal of the Linnean Society 155 (4) on pages 767-768, DOI: 10.1111/j.1096-3642.2008.00463.x, http://zenodo.org/record/4635038

SERRULA CONCHARUM SP. NOV. Serrula concharum: species of Serrula with paired seminal vesicles; needles are similar to those of S. maxillaria, 15-Mm long and 5-Mm wide. Pre-cerebral diverticle ends anteriorly of the statocyst. Serrula concharum: Eaglehawk Neck, Australia (Tasmania); exposed intertidal, with fine sand, and with a high density of Mesodesmatidae bivalves of the genus Paphies Lesson, 1830 (October 1993)., Published as part of Schockaert, Ernest R., Curini-Galletti, Marco, Ridder, Wouter De, Volonterio, Odile & Artois, Tom, 2009, A new family of lithophoran Proseriata (Platyhelminthes), with the description of seven new species from the Indo-Pacific and South America, and the proposal of three new genera, pp. 759-773 in Zoological Journal of the Linnean Society 155 (4) on pages 767-768, DOI: 10.1111/j.1096-3642.2008.00463.x, http://zenodo.org/record/4635038

MEIDIAMA URUGUAYENSIS SP. NOV. Meidiama uruguayensis: species of Meidiama with a curved stylet of 80–90-Mm long, accompanied by 19–21 needles of 30–45-Mm long, with a small terminal hook of about one-quarter to one-fifth of the length of the needles; about 50 testes. Meidiama uruguayensis: Río de la Plata, Balneario Las Flores, Departamento de Maldonado (34°48′50″S, 55°20′03″W), Uruguay (type locality); Playa Grande, Uruguay; coarse sand between rocks (18/7/2004). . Meidiama uruguayensis: four whole mounts and ten sectioned individuals (13 slides) from the type locality; one of the whole mounts is designated as the holotype (SMNH 7352); paratypes UH 371–380. Etymology: Meidiama uruguayensis has been named after the country where it was found., Published as part of Schockaert, Ernest R., Curini-Galletti, Marco, Ridder, Wouter De, Volonterio, Odile & Artois, Tom, 2009, A new family of lithophoran Proseriata (Platyhelminthes), with the description of seven new species from the Indo-Pacific and South America, and the proposal of three new genera, pp. 759-773 in Zoological Journal of the Linnean Society 155 (4) on pages 760-761, DOI: 10.1111/j.1096-3642.2008.00463.x, http://zenodo.org/record/4635038

SERRULA MAXILLARIA SP. NOV. Serrula maxillaria: species of Serrula with a single seminal vesicle. Atrial needles are 13-Mm long and 3-Mm wide over the whole length, and have a truncated and serrated distal end. The precerebral diverticle ends at the statocyst. Serrula maxillaria: Cairns, Australia (Queensland); protected beach at Yorkney’s Knob, with fine to midfine sand (October 1993)., Published as part of Schockaert, Ernest R., Curini-Galletti, Marco, Ridder, Wouter De, Volonterio, Odile & Artois, Tom, 2009, A new family of lithophoran Proseriata (Platyhelminthes), with the description of seven new species from the Indo-Pacific and South America, and the proposal of three new genera, pp. 759-773 in Zoological Journal of the Linnean Society 155 (4) on page 767, DOI: 10.1111/j.1096-3642.2008.00463.x, http://zenodo.org/record/4635038

Nemertodermatida is a taxon of small, acoelomate, marine, interstitial worms without a true gut but with a statocyst containing multiple statoliths. Their phylogenetic position is still the subject of debate. This has raised growing interest in the study of this group, on both the molecular and the morphological level. Nemertodermatida have not yet been reported in the Belgian part of the North Sea, and they are known to be sparse. After sampling on different locations in the Belgian part of the North Sea with a Van Veen grab, we were able to collect three different species of Nemertodermatida: Flagellophora apelti, Nemertinoides elongatus and Sterreria psammicola. These were fixed and are currently being used for morphological studies. In order to increase the morphological knowledge on this challenging group, we study the germline in Nemertodermatida, in comparison to that of Acoela. As the structure of the gonads in Acoela and Nemertodermatida is variable and complex, light and transmission electron microscopy are used to define the spatial arrangement, characteristics and organization of the testes and ovaries in different species. We assess the potential of the morphological characteristics of the germline as a complement to the molecular data in the discussion of the evolutionary relationships within and between these intriguing groups.

Acirrostylus poncedeleoni n.g. n.sp. (Figs. 1���2) Locality. La Coronilla, Departamento de Rocha, Uruguay (33 �� 54 ���18.50���S, 53 �� 30 ���39.30���W). Beach and mouth of the canal near hotel Parque Oc��anico: sand covered by a thin green layer of organic material, and sand with organic material near a small pool in open contact with the ocean (01/08/ 2004): type locality. Material. Observations on a live animal. Two whole mounts, one of which designated holotype (SMNH 7495), and two serially-sectioned specimens, one of which designated paratype (HU no. 400). Etymology. The genus name refers to the lack of a cirrus and the presence of a stylet. The species is dedicated to Prof. Dr. Rodrigo Ponce de Le��n (Montevideo, Uruguay). Description. The animal is about 0.5 mm long and has two eyes. The syncytial epidermis is strongly ciliated and �� 2���3 ��m thick in the rostral and caudal part of the animal. In the central part it is �� 1���2 ��m thick. Cilia are �� 2 ��m long. Small round to oval nuclei with a diameter half of the epidermis height occur throughout the epithelium. Round rhabdites of a similar size to the nuclei are present in the apical part of the epidermis. They are most numerous on the dorsal side of the animal. The basal membrane is very thin. Circular and longitudinal muscle layers are successively present under the very thin basal membrane. The proboscis is about 1 / 6 to 1 / 7 of the body length long (�� 70���80 ��m). The proboscis glands run anteriorly through the muscular bulb to form a girdle of eight coarse-grained eosinophilic glandular ampullae. In between these ampullae, small muscles run from the cone to the peripheral wall of the proboscis. The convex cone is completely filled with a darkly-staining substance, possibly a glandular secretion, although its origin could not be traced. The proboscis bulb is provided with well-developed longitudinal muscles, surrounded by circular muscles. The latter do not surround the glandular girdle. The epithelium of the proboscis sheath lacks cilia. Anteriorly it is membranous and anucleated. Here the sheath is surrounded by small basophilic glands, but whether they empty into the lumen of the proboscis sheath or more frontally is not fully clear. The epithelium of the sheath becomes higher and nucleated near the proboscis bulb, where it is surrounded by circular muscles. These continue for a short distance around the anterior part of the glandular girdle. The different sets of motional muscles are not fully visible in the serial sections. Parts of the protractors run around the proboscis bulb. Relatively thick muscle fibers, which probably function as dilators, insert at the transition zone between the sheath and the glandular girdle. Fixators insert on the bulbar septum just below the glandular girdle and adhere on the epidermal basal membrane at the same level where the integument retractors insert. The latter were observed dorsally as well as ventrally and run posteriorly to the body wall. Posterior to the proboscis bulb, remnants of the proboscis retractors were visible. Their insertion place could not, however, be verified. The pharynx rosulatus is situated in the first body half, posterior to the proboscis, brain and eyes. In the serial sections, the pharynx is somewhat shifted rostrally with regard to the position that was observed in the live animal. The mouth is situated at approximately 35 %. The pharynx contains eosinophilic and basophilic glands; the exact location of their opening into the pharynx lumen could not be determined. The pharynx bulb is surrounded by a circular muscle layer. These muscles are more developed around the distal part of the bulb. The tube-shaped lumen is lined with a membranous epithelium surrounded by outer circular and inner longitudinal muscles. The membranous epithelium of this lumen is probably ciliated, but this could not be confirmed. The prepharyngeal cavity is also lined with a membranous epithelium and is only surrounded by a circular muscle layer. Glands of Minot empty into the oesophagus. A bundle of eosinophilic and basophilic glands is situated caudally from the brain. The paired testes are located at both ventrolateral sides of the animal. In the serial sections they are situated at approximately 50 % of the body length. However, in the live animal they were observed more caudally. A vas deferens leaves from each testis, distally broadening to form a seminal vesicle. Just before entering the copulatory bulb, the vasa deferentia join to form the ejaculatory duct. This ejaculatory duct runs centrally through the prostate vesicle (conjuncta-type copulatory organ; terminology of Karling 1956 a). The prostate vesicle contains fine- and coarse-grained eosinophilic prostate glands. Only the fine-grained glands are extracapsular. The prostate vesicle is lined with a membranous, anucleated epithelium and surrounded by an inner circular and an outer longitudinal muscle layer. The outer longitudinal layer continues around the male atrium. Distally the prostate glands and the ejaculatory duct enter the stylet, which is a single-walled, slightly curved tube, 62 ��m long. Its proximal end is funnel-shaped, and somewhat asymmetrical. For approximately 2 / 3 of its length, the stylet forms two lateral, wing-like protrusions, which give the impression of forming a sheath around the stylet. The distal blunt end of the stylet shows a round opening. The ovary is unpaired and lies in the middle of the body at the dorsal side. The vitellarium runs rostrally to the proboscis and is caudally connected with the ovary to form an ovovitellarium. In the live animal, two lateral branches of this vitellarium were observed. A long oviduct connects the ovary with the female duct. This oviduct is lined with a membranous, anucleated epithelium and not surrounded by muscles. The female duct is strongly widened and surrounded by a longitudinal muscle layer. It is lined with a rather high, degenerated epithelium. Where the female duct enters the common genital atrium, it is surrounded by a weak circular muscle layer. The elongated bursa enters the common genital atrium. Dorsally, a sphincter divides the bursa into a small, thin-walled proximal part and a broad, muscular distal part. The latter is very darkly stained in the serial sections and apparently lined with a very high epithelium. Where the bursa enters the common genital atrium, it is surrounded by a circular muscle layer and lined with a high epithelium. The rest of the distal bursal part is surrounded by a longitudinal muscle layer. Proximally from the sphincter, two cuticularized spermatic ducts originate. These ducts run towards the ovary and the oviduct, but their exact proximal ends could not be ascertained. A possible connection between the ovary and the proximal part of the bursa could not be observed. The common genital atrium is surrounded by a circular muscle layer and lined with a membranous, anucleated epithelium. Ventrocaudally the common genital atrium empties into the gonopore, which is surrounded by a sphincter. The caudal body region contains eosinophilic and basophilic caudal glands. Discussion. The presence of a proboscis without hooks and muscular plates, but with a glandular girdle, places Acirrostylus poncedeleoni n.sp. clearly within the taxon Cicerinidae Meixner, 1928. Traditionally, the family Cicerinidae is subdivided into three subfamilies: Cicerininae Meixner, 1928, Nannorhynchidinae Evdonin, 1977, and Xenocicerininae Evdonin, 1977, the last containing a single genus (Xenocicerina Karling, 1956). Morphological analyses of sperm (Watson 1998) and proboscis ultrastructure (De Vocht 1992; De Vocht & Schockaert 1999) strongly suggest a monophyletic Nannorhynchidinae. All representatives of Nannorhynchidinae show a reduction of the axonemata in the sperm, similar to the situation found in the Schizorhynchia, which makes them a possible sister group to the Schizorhynchia (Watson 1998, 2001). Moreover, all species within Nannorhynchidinae have eyes with lenses, which is clearly not the case for the other species of Cicerinidae. Most probably the taxon Cicerininae is not monophyletic, and even not related to the Nannorhynchidinae. The presence of sensory organs associated with the distal belt of the sheath epithelium suggests a close relationship of Cicerina remanei Meixner, 1928 with Psammorhynchus tubulipenis Meixner, 1938 (Psammorhynchidae Karling, 1956) and Cytocystis clitellatus Karling, 1953 (Cytocystididae Karling, 1964) (De Vocht 1990; De Vocht & Schockaert 1999). These taxa possibly form a larger monophyletic group, together with species of Ethmorhynchus Meixner, 1928, Ptyalorhynchus Meixner, 1938, Paracicerina Meixner, 1928, Xenocicerina Karling, 1956, Placorhynchidae and Gnathorhynchidae, based on the presence of two sets of proboscis retractors (De Vocht 1992). Ethmorhynchus, Ptyalorhynchus, Cicerina and Paracicerina differ from the other taxa within this group by the fact that they all have a nucleo-glandular girdle associated with the proboscis. Species of Zonorhynchus Karling, 1952 and Didiadema Brunet, 1965 have a nucleo-glandular girdle, but have only one set of proboscis retractors. Acirrostylus poncedeleoni n.sp. does not have eyes with lenses, which places it outside the Nannorhynchidinae. It clearly differs from the typical species of ��� Cicerininae ��� by the lack of nuclei in the glandular girdle. A typical feature of A. poncedeleoni n.sp. is the presence of a stylet, a feature which it shares only with some species of Zonorhynchus, a taxon traditionally placed within the Cicerininae. However, species of Zonorhynchus also have an armed cirrus which is lacking in A. poncedeleoni n.sp. The most typical feature of Acirrostylus n.g., however, is the fact that there is only one ovovitellarium, a situation that is unique within the Cicerinidae. Moreover, a uterus is completely lacking, which is also very unusual within the Cicerinidae. Some species of Nannorhynchidinae have a well-developed uterus, whereas in the other Cicerininae and Xenocicerina, the uterus is weakly differentiated, often being no more than a small protrusion of the common genital atrium. All Cicerinidae, except for Toia and Zonorhynchus, have cuticularized spermatic ducts of variable length, which connect the bursa to the ovovitellaria. Although this connection could not be observed in the Uruguayan species, this is probably also the case for A. poncedeleoni n.sp. From the discussion above it is clear that the species from Uruguay cannot be placed in any of the existing genera, and therefore a new genus is erected. The phylogenetic relationships between the different cicerinid taxa is far from clear, and should be established in a large phylogenetic study. Diagnosis. Acirrostylus n.g.: small taxon of Cicerinidae with a girdle of eight separate eosinophilic glandular proboscis ampullae and two sets of proboscis retractors. Nuclei absent in the glandular girdle. Eyes without lenses. Pharynx in the anterior part of the body. Copulatory organ with stylet, without cirrus. Paired testes and seminal vesicles. Unpaired ovovitellarium. Large bursa composed of a distal and a proximal part separated by a sphincter. Two cuticularized spermatic ducts. Uterus absent. Type species: A. poncedeleoni n.sp. Diagnosis. Acirrostylus poncedeleoni n.sp.: provisionally with the same diagnosis as the genus. The stylet is a 62 �� m long tube with wing-like, lateral protrusions., Published as part of Steenkiste, Niels Van, Volonterio, Odile, Schockaert, Ernest & Artois, Tom, 2008, Marine Rhabdocoela (Platyhelminthes, Rhabditophora) from Uruguay, with the description of eight new species and two new genera, pp. 1-33 in Zootaxa 1914 on pages 4-8, DOI: 10.5281/zenodo.184571, {"references":["Karling, T. G. (1956 a) Morphologisch-histologische Untersuchungen an den manlichen Atrialorganen der Kalyptorhynchia (Turbellaria). Arkiv for Zoologi, 9, 187 - 277.","Meixner, J. (1928) Aberrante Kalyptorhynchia (Turbellaria: Rhabdocoela) aus dem Sande der Kieler Bucht. Zoologischer Anzeiger, 77, 229 - 253.","Evdonin, L. A. (1977) Turbellaria Kalyptorhynchia in the fauna of USSR and adjacent areas. Fauna USSR (N. S.), 115, 1 - 400 (In Russian).","Watson, N. A. (1998) Spermiogenesis and eyes with lenses in two kalyptorhynch flatworm species, Toia calceformis and Nannorhynchides herdlaensis (Eukalyptorhynchia, Platyhelminthes). Invertebrate Biologie, 117, 9 - 19.","De Vocht, A. J-P. (1992) Anatomy and ultrastructure of the proboscis in Eukalyptorhynchia (Plathelminthes, Rhabdocoela). PhD, Limburgs Universitair Centrum, Belgium, 260 pp.","De Vocht, A. J-P. & Schockaert, E. R. (1999) The anatomy and ultrastructure of the proboscis in Zonorhynchus - species and implications for phylogenetic relationships within the Eukalyptorhynchia Meixner, 1928 (Platyhelminthes, Rhabdocoela). Belgian Journal of Zoology, 129, 219 - 234.","Watson, N. A. (2001) Insights from comparative spermatology in the ' turbellarian' Rhabdocoela. In: Littlewood, D. T. & Bray, R. A. (Ed.) Interrelationships of the Platyhelminthes. Taylor and Francis, London-New York, pp. 217 - 230.","Meixner, J. (1938) Turbellaria (Strudelwurmer). Die Tierwelt der Nord- und Ostsee, 33, 1 - 146.","Karling, T. G. (1953) Cytocystis clitellatus n. gen., n. sp., ein neuer Eukalyptorhynchien-Typus (Turbellaria). Arkiv for Zoologi, 4, 493 - 505.","Karling, T. G. (1964) Uber einige neue und ungugend bekannte Turbellaria Eukalyptorhynchia. Zoologischer Anzeiger, 172, 159 - 183.","De Vocht, A. J-P. (1990) The ultrastructure of the proboscis in Psammorhynchus tubulipenis Karling, 1964 and Cytocystis clitellatus Karling, 1953 (Platyhelminthes, Rhabdocoela). Acta Zoologica, 71, 113 - 124.","Karling, T. G. (1952) Studien uber Kalyptorhynchia (Turbellaria). IV. Einige Eukalyptorhynchia. Acta Zoologica Fennica, 69, 1 - 49.","Brunet, M. (1965) Turbellaries Calyptorhynques de substrats meubles de la region de Marseille. Recueil des Travaux de la Station Marine d'Endoume, 39, 127 - 219."]}

Cincturorhynchus karlingi Schockaert, 1982 Known distribution. Somalia: N of Mogadiscio (Hawadli) (Schockaert 1982). McKenzie Point, Mombasa, Kenya (Jouk & De Vocht 1989). New localities in the Indian Ocean. McKenzie Point, Mombasa (Kenya): red and green algae from a shallow tide pool sheltered behind some rocks, eulittoral (27 /09/ 1991); same locality: tufts of fine-branched algae on a large beach and from a shallow tide pool a short distance past the Four Seasons Restaurant at the second obelisk (01/ 10 / 1991); same locality: on arboriform brown algae from a tide pool on rocks at about 15 m from the roundabout at the Four Seasons Restaurant (01/ 10 / 91); same locality: little algae from a rocky tide pool at and a short distance past the fence of the Four Seasons Restaurant (10 / 10 / 1991). Zanzibar (Tanzania): Mbweni, beach behind the Mbweni Ruins Hotel, north of the creek, in a little pool with seagrass (Thallasia spec?) (17 / 8 / 1995). Material. Type material and other material of the original description. Several animals from Kenya and two from Zanzibar studied alive and whole mounted. Three sectioned specimens from Kenya. Remarks. Habitus and internal organisation of the Kenyan and Tanzanian specimens correspond to the description by Schockaert (1982). On the new material the length of prostate stylet type II varies between 23��� 31 ��m (= 28, n = 6), with a basal ring of 15���23 ��m diameter (= 20, n = 6). These measurements differ quite considerably from those given in the original description for the holotype (50 ��m and 30 ��m respectively). However, re���measuring of these parts in the holotype revealed a prostate stylet type II of only 25 ��m long, with a basal ring of 17 ��m diameter, corresponding to the measurements on the new material. In the holotype, five spines emerge from this ring. In the new specimens we counted 4���7 spines, depending on the orientation of the stylet. The prostate stylet type III can appear differently depending on the degree of compression, but mostly its structure as described in the original description (Schockaert 1982) is easily recognised. However, because of its complexity, measurements on the prostate stylet type III are difficult to compare and the diameter lies between 25 (holotype) and 56 ��m. The construction of the female system is rather difficult to assess. Only one of the sectioned specimens from Kenya is in acceptable condition to be studied. The insemination ducts are not visible in this specimen. However, the swollen spermatic ducts (���seminal receptacles��� of Schockaert 1982) are clearly visible. The female system should be studied on better material; we suppose that the Kenyan and Tanzanian populations do not differ from the Somali population as to construction of the female system., Published as part of Artois, Tom J. & Tessens, Bart S., 2008, Polycystididae (Rhabditophora: Rhabdocoela: Kalyptorhynchia) from the Indian Ocean, with the description of twelve new species, pp. 1-27 in Zootaxa 1849 on page 6, DOI: 10.5281/zenodo.183373, {"references":["Schockaert, E. R. (1982) Turbellaria from Somalia II. Kalyptorhynchia (Part 2). Monitore Zoologico Italiano (N. S.), Suppl. 17, 81 - 96.","Jouk, P. E. H. & De Vocht, A. J. - P. (1989) Kalyptorhynchia (Plathelminthes Rhabdocoela) from the Kenyan coast, with descriptions of four new species. Tropical Zoology, 2, 145 - 157."]}

Paulodora drepanophora n. sp. (Figs 3 F, 4 G) Syn. Polycystis contorta in Schockaert (1982) and in Jouk & De Vocht (1989) Localities in the Indian Ocean. Widespread along the African East Coast. McKenzie Point, Mombasa (Kenya), small algae from a rocky tide pool at the fence of the Four Seasons Restaurant (10 / 10 / 1991) (type locality). Same locality, at the mouth of Tudor Creek, on Thalassia hemprichii, covered by the epiphyte Enteromorpha kylinii in pools at the rocky shore at low tide (Jouk & De Vocht 1989); same locality, a little beyond the Four Seasons Restaurant before the first obelisk, on sea grass (Thalassia) mixed with some red algae and mud from a very shallow tide pool in the mid eulittoral (27 /09/ 1991); Tiwi (Kenya), on sea grass (Halodule) from the mid- to upper eulittoral (06/ 10 / 1991); same locality, tufts of small algae from pools on the reef front (06/ 10 / 1991). Somalia, north of Mogadiscio (Hawadli and Warshek), on algae from pools on the rocky shore at low tide (Schockaert 1982). Material. Several animals studied alive in the different localities. Several whole mounts from the different localities (one of them designated holotype, SMNH, no. 7446) and three sectioned specimens from Kenya. Etymology. The stylet is sickle-shaped. Drepanos (Gr.): sickle, phorein (Gr.): to carry. Description. Habitus and internal organisation as in P. felis (see Marcus 1954; Artois & Schockaert 2001) The double-walled prostate stylet type I has a short, slightly curved to straight proximal part. In this part the inner stylet is clearly visible; the outer stylet appears to be twisted. Distally the outer stylet forms a large flap-like projection, which initially runs perpendicular to the stylet proper. More distally it makes a semicircular turn, tapering towards its blunt distal end. It is not entirely clear whether the inner stylet is restricted to the proximal part (and hence the distal part is nothing more than a projection), or whether the inner stylet continues into the distal part, making it a part of the stylet proper. At least in the holotype the former situation seems to be true. As a whole the stylet has the appearance of a sickle, with the stylet proper forming the grip and the flap-like projection the blade. All together it is 42���62 ��m long (x = 53, n = 9). In one of the sectioned animals, there is a separate sperm-receiving compartment connected to the left oviduct. This was not found in any of the other sectioned animals, and more material is needed to confirm this observation. Diagnosis. Species of Paulodora with a prostate stylet type I ca 53 ��m long, sickle-shaped. Proximal part short, straight to slightly curved, with a twisted outer stylet. Inner stylet only present in the proximal part, distal blade-like part thus only a projection (?). Bursal stalk very short. With long-drawn, kidney-shaped ovaries. Seminal receptacles absent (?). Discussion. See the discussion on P. w a t s o n i n. sp., Published as part of Artois, Tom J. & Tessens, Bart S., 2008, Polycystididae (Rhabditophora: Rhabdocoela: Kalyptorhynchia) from the Indian Ocean, with the description of twelve new species, pp. 1-27 in Zootaxa 1849 on page 14, DOI: 10.5281/zenodo.183373, {"references":["Schockaert, E. R. (1982) Turbellaria from Somalia II. Kalyptorhynchia (Part 2). Monitore Zoologico Italiano (N. S.), Suppl. 17, 81 - 96.","Jouk, P. E. H. & De Vocht, A. J. - P. (1989) Kalyptorhynchia (Plathelminthes Rhabdocoela) from the Kenyan coast, with descriptions of four new species. Tropical Zoology, 2, 145 - 157.","Marcus, E. (1954) Turbellaria Brazileiros (11). Papeis avulsos do Departemento de Zoologia-Secrataria da Agricultura- S. Paulo-Brazil, 11, 419 - 489.","Artois, T. J. & Schockaert, E. R. (2001) Interstitial fauna of the Galapagos: Duplacrorhynchinae, Macrorhynchinae, Polycystidinae, Gyratricinae (Platyhelminthes Polycystididae). Tropical Zoology, 14, 63 - 85."]}

Paraustrorhynchus neleae n. sp. (Fig. 2 A���C, H���I) Localities in the Indian ocean. English Point, Mombasa (Kenya): at 6 m depth on Thalassia hemprichii, partly covered with the epiphyte Syringodium isoetifolium (09/06/ 1987) (type locality). Kanamai, Mombasa (Kenya): flattened red algae from a big tide pool on the reef, �� 1 km south of the institute (15 / 10 / 1992). Zanzibar Island (Tanzania): Mbweni, beach behind the Mbweni Ruins Hotel, north of the creek, in a tide pool with a broad-leafed seagrass (17 /08/ 1995). Material. Several animals studied alive. Three whole mounts from the type locality; one of them designated holotype (SMNH, no. 7443), the other two paratype (HU, nos. 353-354). One whole mount from each of the other localities. Etymology. Named after Nele Spelmans, wife of TA. Description. The animals are opaque, brown-green pigmented on the dorsal surface, the ventral surface is unpigmented. They are 0,6���0,9 mm long (measured on whole mounts), with two eyes. The proboscis is rather small, only about 1 / 7 of the body length long. The pharynx is in the first body half and slightly inclined forwards. The gonads are paired. The two testes are rather small and lie at the level of the pharynx. The ovaries are situated in the caudal body end. The vitellaria extend at both sides of the body from the eyes to the rear end of the body. Male and female atrial system as in P. pacificus Karling & Schockaert, 1977. There are two hard parts in the proximal part of the male atrium: a prostate stylet type II (Fig. 2 B) and a prostate stylet type III (Fig. 2 C). The prostate stylet type II is double-walled. At about its midpoint, it makes a 90 �� turn, which makes the curved distal part of the stylet run perpendicular to the proximal part. Distally the stylet tapers gradually to end in a sharp point. The inner stylet can be followed almost over the whole length of the outer stylet. Only in the proximal 1 / 5 is it lacking. At one side, the proximal part of the outer stylet shows a longitudinal slit (Fig. 2 B, indicated by an arrow), which broadens at the level of the proximal end of the inner stylet, leaving the inner stylet apparently uncovered at this side. The prostate stylet type II is 64���74 ��m long (= 71, n = 5). An ovoid prostate vesicle type II is connected to this stylet. It has a very thick muscular wall. The prostate stylet type III (Fig. 2 C) consists of two long arms, proximally connected to a single broad folded plate. These arms extend from the two proximal corners of the plate, curving towards each other and broadening distally. The distal ends are very broad and are provided with teeth (often very difficult to see on the smallest of the two arms). The muscles surrounding the male atrium form a thick muscular bulb at the proximal end of this stylet. Measurements of the prostate stylet type III (6 specimens): length 24 ��� 37 ��m (= 29); proximal width: 39���42 ��m (= 40); width in the middle: 5���9 ��m (= 7); distal width 18���39 ��m (= 31). Some glands are associated with the prostate stylet type III, probably a prostate vesicle type III. The seminal vesicles are relatively small. The short ejaculatory duct enters the proximal part of the male atrium near to the prostate stylet type III. The male atrium is very broad and muscular. At one side it has a large fold in which large amounts of sperm were observed. Diagnosis. Species of Paraustrorhynchus Karling & Schockaert, 1977, with a prostate stylet type II of ca 71 ��m long, that makes a 90 �� turn at about its midpoint. Distal end very sharp. Outer stylet leaves the inner stylet partly uncovered proximally. Prostate stylet type III consisting of a common proximal plate from which two arms depart. Both arms curved towards each other, with broad distal ends showing broad teeth. Prostate stylet type III ca 29 ��m long, proximally ca 40 ��m, in the middle ca 7 ��m and distally ca 31 ��m broad. Without female bursa. Discussion. P. n e l e a e shows all the diagnostic features of the taxon Paraustrorhynchus (see Karling & Schockaert 1977). Only the absence of insemination ducts should be checked on sections, but as the rest of the organisation as observed in living animals and whole mounts is completely as in Paraustrorhynchus, we presume that insemination ducts are indeed lacking in the new species. Until now, only three species of Paraustrorhynchus were known: P. e l i x u s, P. caligatus Willems et al., 2006 and P. pacificus. In P. e l i x u s the prostate stylet type II is a very small hook, while its prostate stylet type III is clearly bipartite. This is not the case in the three other species, which have a rather long prostate stylet type II and a prostate stylet type III that consists of a common proximal base from which two arms depart. Moreover, in P. elixus a female bursa is present, 1 which is lacking in the other three species. All these differences cast some doubts on the relationship between P. e l i x u s and the other species of Paraustrorhynchus (see also Karling & Schockaert 1977), but for the time being, i.e. before a proper cladistical analysis of the entire taxon Polycystididae is carried through, we refrain from splitting the genus. The fact that the distal half of the prostate stylet type II runs perpendicular to the proximal half clearly distinguishes P. n e l e a e from P. pacificus, where the prostate stylet type II is evenly curved. Moreover stylet type II is almost twice as long in P. pacificus (�� 125 ��m) as it is in P. neleae (�� 71 ��m). The prostate stylet type III is very similar in both species, with the two arms widening abruptly distally. The distal rims of both arms are completely serrated in P. neleae. In P. pacificus one of the arms has a completely serrated distal rim, while the other one is somewhat forked, with one small, serrated part and the other one not serrated. Also prostate stylet type III is much larger in P. pacificus (�� 140 ��m long) than in P. n e l e a e (�� 29 ��m long). P. c a l i g a t u s also resembles P. n e l e a e and P. pacificus, but differs from both in that the prostate stylet type II is straight and typically boot-shaped (see Willems et al. 2006 b). It is even smaller than in P. neleae (�� 49 ��m). The prostate stylet type III of this species is very different from that of both P. pacificus and P. neleae as the arms broaden evenly towards their distal ends, giving them the shapes of broad plates (see Willems et al. 2006 b). This stylet is a bit larger (�� 37 ��m long) than it is in P. n e l e a e., Published as part of Artois, Tom J. & Tessens, Bart S., 2008, Polycystididae (Rhabditophora: Rhabdocoela: Kalyptorhynchia) from the Indian Ocean, with the description of twelve new species, pp. 1-27 in Zootaxa 1849 on pages 10-11, DOI: 10.5281/zenodo.183373, {"references":["Karling, T. G. & Schockaert, E. R. (1977) Anatomy and systematics of some Polycystididae (Turbellaria, Kalyptorhynchia) from the Pacific and S. Atlantic. Zoologica Scripta, 6, 5 - 19.","Willems, W., Schockaert, E. & Artois, T. (2006 b) Report on the Polycystididae (Kalyptorhynchia, Rhabdocoela) from Australia, with the description of 12 new species and 6 new genera. Hydrobiologia, 563, 329 - 355."]}

Oneppus lacus Marcus, 1954 (Fig. 3) New locality. Playa Ram��rez, Departamento de Montevideo, Uruguay (34 �� 54 ���58.55���S, 56 �� 10 ���11.70���W). Beach with numerous holes of invertebrates, upper to lower eulittoral, relatively coarse sand with a large amount of fine fraction (12 /08/04); same locality, mid-eulittoral, rather coarse sand from a sheltered area with a large amount of fine fraction (12 /08/04); same locality, fine sand with large amounts of detritus from a tidal pool in the lower eulittoral (12 /08/04). Known distribution. Itanhaen, Brazil (Marcus 1954). Material. One drawing of a live animal. Several whole mounts, some in bad condition, and three seriallysectioned specimens, all of rather poor quality. Original material from Oneppus lacus Marcus, 1954: SMNH 95815. Original material from Oneppus timius Marcus, 1952: SMNH 95805, SMNH 95806, SMNH 95807, SMNH 95808, SMNH 95809, SMNH 95810, SMNH 95811, SMNH 95812, SMNH 95813, SMNH 95914. Additional remarks and discussion. The body length of the studied specimens ranges from 0.7 to 0.8 mm. Habitus and internal organisation correspond to those of Oneppus timius Marcus, 1952 and Oneppus lacus Marcus, 1954 (see Marcus 1952, 1954). However, O. timius is normally larger (1.2 mm) than O. lacus (0.6 mm). The syncytial epidermis is ciliated and has a height of 1���2 ��m. The cilia are as long as the epidermis is high, and the basal membrane is about �� of the epidermis height. As already mentioned by Marcus (1952) in the description of O. timius, the nuclei in the epithelium of the epidermis are most numerous at both body ends. The proboscis and the pharynx of the studied individual also correspond completely to those of the species of Oneppus described by Marcus (1952, 1954). The construction of the male system greatly resembles that of O. lacus as described by Marcus (1952, 1954). On the serial sections, the ejaculatory duct seems to be slightly sclerotized. However, this could not be confirmed in the whole mounts. Although Marcus (1952, 1954) does not mention it, this could also be observed in one of the original serial sections of O. timius, provided by the SMNH. The cirrus of the Uruguayan specimens is armed with hundreds of small spines. In some whole mounts and in one of the serial sections, a proximal crown of larger spines was clearly observed (arrow in fig. 3 C). Distally, the cirrus is armed with very large, curved spines. According to the description given by Marcus (1954) this type of cirrus is also found in O. lacus, as opposed to O. timius, which has only one, proximal girdle of large spines. For O. lacus, only one slide of serial sections of rather poor quality is available, which makes verification of the original material and comparison with the Uruguayan material very difficult. As far as could be ascertained from the sections of the Uruguayan specimens, the female system is constructed in the same way as in O. lacus and O. timius. It also seems to have a large separate seminal receptacle, completely filled with sperm, as in O. timius. Some uncertainties remain, especially concerning the ventral part of the female system, which was impossible to reconstruct from the serial sections. Based on the relative length of the individuals and the construction of the cirrus, the Uruguayan specimens are placed in O. lacus. Future study should resolve the problems within this genus., Published as part of Steenkiste, Niels Van, Volonterio, Odile, Schockaert, Ernest & Artois, Tom, 2008, Marine Rhabdocoela (Platyhelminthes, Rhabditophora) from Uruguay, with the description of eight new species and two new genera, pp. 1-33 in Zootaxa 1914 on pages 8-10, DOI: 10.5281/zenodo.184571, {"references":["Marcus, E. (1954) Turbellaria brasileiros (11). Boletins da Faculdade de Filosofia, Ciencias e Letras Universidade de Sao Paulo, Zoologia, 24, 419 - 489.","Marcus, E. (1952) Turbellaria brasileiros (10). Boletins da Faculdade de Filosofia, Ciencias e Letras Universidade de Sao Paulo, Zoologia, 17, 5 - 187."]}

Paulodora schockaerti n. sp. (Fig. 4 A���B, G) Localities in the Indian Ocean. Zanzibar Island (Tanzania): off Maruhubi Palace ruins, in the sand of an exposed sea grass field, very rich in detritus (05/08/ 1995) (type locality); beach behind the Mbweni Ruins Hotel, south of the creek, in a higher part of a sand flat with relatively coarse sand (11 /08/ 1995); same locality, north of the creek, in a little pool with sea grass (Thalassia) (17 /08/ 1995). Mombasa (Kenya), Kanamai, coarse shell debris with a silty fraction and a little detritus from a tide pool (20 / 10 / 1992). Material. Several animals studied alive. Four whole-mounted specimens (one from each locality), one of them designated holotype (SMNH, no. 7449). One serially sectioned animal from Zanzibar (Mbweni). Etymology. Named after Prof. Em. Dr. E. Schockaert, for his contributions to polycystidid taxonomy and systematics. Description. Habitus, construction of pharynx and proboscis and general organisation of the female system do not deviate from these in P. contorta (see Schockaert & Karling 1975). The double-walled hookshaped prostate stylet type I is 74���79 ��m long (= 77, n = 3). The specimen from Kenya has a slightly shorter stylet, only 62 ��m long. The proximal straight part of the outer stylet forms a semitubular fold in which the ejaculatory duct drains the sperm. Distally it turns to the other side of the stylet and continues as a large rounded plate, which narrows towards the distal tip of the stylet. The ovaries are globular to oval-shaped with the oocytes closely packed together. Each oviduct is provided with a seminal receptacle, completely filled with sperm. The seminal receptacles narrow towards the oviducts. A smaller globular vesicle, also filled with sperm, is connected to the distal part of each of the seminal receptacles. Distally from the seminal receptacles, each oviduct merges with the male bursa. This bursa is connected to the male atrium by a long and narrow bursal stalk, which is covered by a pseudocuticula. Diagnosis. Species of Paulodora with the prostate stylet type I hook-shaped, ca 77 ��m long (only 62 ��m in one specimen from Kenya). Outer stylet proximally forming a semitubular fold, extending distally as a rounded plate that narrows towards the distal tip of the stylet. Bursal stalk long and narrow, covered by pseudocuticula. Ovaries globular. Each oviduct with a seminal receptacle, which in turn is connected to a smaller globular vesicle, also filled with sperm. Discussion. See the discussion on P. w a t s o n i n. sp., Published as part of Artois, Tom J. & Tessens, Bart S., 2008, Polycystididae (Rhabditophora: Rhabdocoela: Kalyptorhynchia) from the Indian Ocean, with the description of twelve new species, pp. 1-27 in Zootaxa 1849 on page 16, DOI: 10.5281/zenodo.183373, {"references":["Schockaert, E. R. & Karling, T. G. (1975) Anatomy and taxonomy of some species of Polycystididae (Turbellaria, Kalyptorhynchia) from N. Atlantic and Mediterranean coastal areas. Zoologica Scripta, 4, 133 - 143."]}

Paulodora ancora n. sp. (Figs 3 A, 4 E) Localities in the Indian Ocean. Zanzibar Island (Tanzania): beach between the Institute of Marine Sciences and the Floating Restaurant, Ulva -like algae with sand from some rocks beside a stair from the beach to the dike, lower eulittoral at low tide (03/08/ 1995) (type locality); Pete (southern region of Unguja): arborescent algae from a tide pool, which was exposed to the sun, in a mangrove area at low tide (16 /08/ 1995). Material. Three animals studied alive and mounted, one of them designated holotype (SMNH, no. 7444), another one paratype (HU, no. 355). 1. P. elixus was erroneously scored as lacking a female bursa by Artois and Schockaert (2005; Table 1). Etymology. The stylet is anchor-shaped. Ancora (Lat.): anchor. Description. Animals about 1 mm long, without pigmentation and with two eyes. Gonads paired with short testes and elongated ovaries with the oocytes in rows. The internal organisation seems to be identical to that of P. contorta (see Schockaert & Karling 1975). The double-walled prostate stylet type I is 39–46 µm long (x = 43, n = 3). About in its middle it makes a 90 ° turn. At this turn, the outer stylet forms a ± 16 µmlong “spur”, which gives the stylet its typical anchor shape at lower magnifications. From the tip of the spur, two flaps depart, one at each side of the stylet. The proximal rim of the larger one almost reaches the proximal end of the stylet. At the other end, this flap is attached to a small projection of the outer stylet, which is perpendicular to the spur. The smaller flap attaches to the distal part of the stylet. The inner stylet can be followed throughout almost all of the outer stylet. The bursal stalk is rather long and seems to be covered by an epithelium, not a pseudocuticula. We did not observe any sperm in the oviducts, nor in the distal part of the ovaries. Diagnosis. Species of Paulodora with a prostate stylet type I ca 43 µm long, turning about 90 ° about in its middle. Curve with a ca 16 µm long spur. Outer stylet forming two flaps, both attached to the spur at one side. The larger one attached to a small projection of the outer stylet; the smaller one to the distal part of the stylet proper. Bursal stalk relatively long, covered with an epithelium (?). With long-drawn, kidney-shaped ovaries. Seminal receptacles absent. Discussion. See the discussion on P. w a t s o n i n.sp.

Paraustrorhynchus elixus (Marcus, 1954) Karling & Schockaert, 1977 (Fig. 2 D���G, J) Syn. Austrorhynchus elixus Marcus, 1954 Known distribution. The Brazilian coast: Bay of Santos and the Island of S��o Sebasti��o (Marcus 1954). New localities in the Indian Ocean. English Point, Mombasa (Kenya): green algae (5 m) (October 1987). New localities outside the Indian Ocean. New Caledonia, Noum��a, Nouville, algae covered with sediment from the lagoon near to the asylum (10 /08/ 2003). New Caledonia, Noum��a, Magenta, large algae covered with sediment and small epiphytes from a pool on the beach near to the mangrove area (22 /08/ 2003). Material. One animal from Kenya studied alive and mounted. Two whole mounts (including the lectotype) and two serially-sectioned specimens from Brazil (SMNH). One animal studied alive and whole mounted and one sectioned specimen from New Caledonia. Remarks. A detailed description of the species can be found in Marcus (1954), with additions made by Karling & Schockaert (1977). Our observations on the new specimens are completely in accordance with these descriptions. The prostate stylet type II (Fig. 2 E, G) is identical in the specimens from all three localities, and is a simple hook with an asymmetrical proximal opening [not mentioned or depicted by Marcus (1954) or Karling & Schockaert (1977)]. It is very short, only 27 ��m long in the specimen from New Caledonia, 32 ��m in the specimen from Kenya (Fig. 2 E) and 33 ��m in a specimen from Brazil [Fig. 2 G, same specimen as depicted by Karling & Schockaert (1977, Fig. 25)]. The prostate stylet type III (Fig. 2 D, F) [���complex cuticular apparatus��� of Karling & Schockaert (1977)] is very complex, consisting of a stalk and a S-shaped plate that is attached to it. This stylet is easy to study in one specimen from Brazil (Fig. 2 F) and in the specimen from New Caledonia. It is almost identical in both. In the lectotype and in the specimen from Kenya (Fig. 2 D) this stylet is deformed through squashing. Especially on the lectotype it is very difficult to distinguish the different parts of this stylet, and therefore we do not further consider this specimen. The different parts of the prostate stylet type III can, however, be recognised on the specimen from Kenya. These different parts are a stalk, an S-shaped plate and hook, indicated on Figs 2 D & F by a full, striped and dotted arrow respectively. The measurements we took on the different specimens are as follows: Brazil: stalk: 77 ��m, S-shaped plate: 64 ��m, hook: 21 ��m; New Caledonia: stalk: 78 ��m, S-shaped plate: 63 ��m, hook: 17 ��m; Kenya: stalk: 92 (?) ��m, S-shaped plate: 62 ��m, hook: 17 ��m. The stalk of the Kenyan specimen is recurved, and very difficult to measure properly. It might be shorter than indicated here. An overview of the measurements is given in Table 4., Published as part of Artois, Tom J. & Tessens, Bart S., 2008, Polycystididae (Rhabditophora: Rhabdocoela: Kalyptorhynchia) from the Indian Ocean, with the description of twelve new species, pp. 1-27 in Zootaxa 1849 on pages 9-10, DOI: 10.5281/zenodo.183373, {"references":["Marcus, E. (1954) Turbellaria Brazileiros (11). Papeis avulsos do Departemento de Zoologia-Secrataria da Agricultura- S. Paulo-Brazil, 11, 419 - 489.","Karling, T. G. & Schockaert, E. R. (1977) Anatomy and systematics of some Polycystididae (Turbellaria, Kalyptorhynchia) from the Pacific and S. Atlantic. Zoologica Scripta, 6, 5 - 19."]}

Gyratrix hermaphroditus Ehrenberg, 1831 species complex Known distribution. Cosmopolitan and euryhaline, found from pure marine to pure limnic habitats. New localities in the Indian Ocean. Zanzibar Island (Tanzania): beach between the Institute of Marine Sciences and the Floating Restaurant, Ulva -like algae with sand, from rocks beside a stair from the beach to the dike, lower eulittoral at low tide (03/08/ 1995); off Maruhubi Palace ruins, sand flat, coarse sand with some detritus, relatively dry with many crab holes (05/08/ 1995); same locality, open beach with relatively fine sand (05/08/ 1995). Seychelles: Mah��, Grande Anse (Beoli��re), mangrove area, fine sediment from the upper eulittoral (19 / 12 / 1992); same locality, between two mangrove areas, relatively fine sand (15 / 12 / 1992), coarse sand (Amphioxus sand) from 19 m deep from an unknown locality in the Seychelles; Mah��, Baie Beau Vallon, little pool between granite rocks, fine sand (27 / 12 / 1992). McKenzie Point, Mombasa (Kenya): fine, clear sand near to a mangrove area; very fine sand from a rock pool (12 / 10 / 1992); between rocks near the Four Seasons restaurant, dry coarse sand from the upper eulittoral (19 / 10 / 1992), same locality, fine sand with shell gravel, upper eulittoral (19 / 10 / 1992). Kanamai (Kenya): tide pool, coarse shell gravel with very fine sand, mid-eulittoral (20 / 10 / 1992). La R��union: Cap la Houssay, surf zone, coarse sand with pieces of coral (30 / 10 / 1992); Sabine les Bains, very coarse sand from a tide pool (02/ 11 / 1992). South-west Sulawesi (Indonesia): Samolana, Kudingareng Keke, Galesong, Kajangan, all in coral sand from the eulittoral up to 20 deep, all between 30 /09/ 1984 and 22 / 10 / 1984. Material. Four whole mounts from Zanzibar, four whole mounts from the Seychelles, six whole mounts from Kenya, four whole mounts from La R��union and four whole mounts from Indonesia. Remarks. The pioneering researches of Reuter (1961), Heitkamp (1978), L���Hardy (1986) and especially Curini-Galletti & Puccinelli (1989,1990, 1994, 1998), Puccinelli & Curini-Galletti (1987), Puccinelli et al. (1990) and, more recently, Timoshkin et al. (2004) have shown that this ���species��� is actually a large complex of cryptic species. These species differ from each other in karyotype and detailed construction and dimensions of the hard parts in the male system. The organisation of the female system can also differ, some of the species are eyeless and their colour can vary (see Graff 1905, 1911; Artois & Schockaert 2001). The morphological and karyological diversity is not yet fully understood on a worldwide base, and the complex has not formally been split up. It could well be that the species complex is not monophyletic, and that some of the species are more closely related to Gyratrix proavus Meixner, 1929 or Gyratrix proaviformis Karling & Schockaert, 1977. The measurements of the stylet, sheath and stalk of the new material are given in Table 3. They all fall within the range known from the rest of the world. These measurements once again illustrate the huge variation occurring within this species complex. No clear delimitation of cryptic species can be made, probably because of the confounding effect of the existence of multiple sympatric cryptic species, which is known to occur in a very high degree in the species complex (Curini-Galletti & Pucinelli 1990)., Published as part of Artois, Tom J. & Tessens, Bart S., 2008, Polycystididae (Rhabditophora: Rhabdocoela: Kalyptorhynchia) from the Indian Ocean, with the description of twelve new species, pp. 1-27 in Zootaxa 1849 on pages 7-9, DOI: 10.5281/zenodo.183373, {"references":["Ehrenberg C. G. (1831) Animalia evertebrata exclusis insectis recensuit C. G. Ehrenberg. Series prima cum Tabularum decade prima. In: Hemprich, F. G. & Ehrenberg C. G. (Eds.), Symbolae Physicae 2. Phytozoa Turbellaria. Officina Academica, Berolina, pp. 1 - 15.","Reuter, M. (1961) Untersuchungen uber rassenbildung bei Gyratrix hermaphroditus (Turbellaria Neorhabdocoela). Acta Zoologica Fennica, 100, 101 - 122.","Heitkamp, U. (1978) Speciationsprozesse bei Gyratrix hermaphroditus Ehrenberg, 1831 (Turbellaria, Kalyptorhynchia). Zoomorphology, 90, 227 - 251.","Puccinelli, I & Curini-Galletti, M. C. (1987) Chromosomal evolution and speciation in marine populations of Gyratrix hermaphroditus sensu lato (Platyhelminthes: Kalyptorhynchia) and in other species of the Gyratricinae. Transactions of the American Microscopical Society, 106, 311 - 320.","Graff, L. von (1905) Marine Turbellarien Orotavas und der Kusten Europas. Ergebnisse einiger, mit Unterstutzung der kais. Akademie der Wissenschaften in Wien (aus dem Legate Wedl) in den Jahren 1902 und 1903 unternommen Studienreise. II. Rhabdocoela. Zeitschrift fur Wissenschaftlichen Zoologie, 83, 68 - 148.","Graff, L. von (1911) Acoela, Rhabdocoela und Alloeocoela des Ostens der Vereinigten Staaten von Amerika. Mit Nachtragen zu den \" Marinen Turbellarien Orotavas und der Kusten Europas \". Zeitschrift fur Wissenschaftlichen Zoologie, 99, 1 - 108.","Artois, T. J. & Schockaert, E. R. (2001) Interstitial fauna of the Galapagos: Duplacrorhynchinae, Macrorhynchinae, Polycystidinae, Gyratricinae (Platyhelminthes Polycystididae). Tropical Zoology, 14, 63 - 85.","Meixner, J. (1929) Morphologisch-okologische Studien an neuen Turbellarien aus dem Meeressande der Kieler Bucht. Zeitschrift fur Morphologie und Okologie der Tiere, 14, 765 - 791.","Karling, T. G. & Schockaert, E. R. (1977) Anatomy and systematics of some Polycystididae (Turbellaria, Kalyptorhynchia) from the Pacific and S. Atlantic. Zoologica Scripta, 6, 5 - 19."]}

Cheliplana triductibus n.sp. (Fig. 4) Locality. Playa Ram��rez, Departamento de Montevideo, Uruguay (34 �� 54 ���58.55���S, 56 �� 10 ���11.70���W). Mid-eulittoral, rather coarse sand from a sheltered area with a large amount of fine fraction (12 /08/04): type locality. Material. Observations on live animals. Three whole mounts, one designated holotype (SMNH 7496), the rest paratypes (HU no. 401���402) and seven serially-sectioned specimens, three of which designated paratypes (HU no. 403���405). Etymology. The species epithet refers to the three sclerotized spermatic ducts and muscular ducts connecting the ovary with the bursa. Tres (Lat.): three. Ductus (Lat.): duct. Description. The body length of the animal varies between 0.7��� 1 mm. Habitus and internal organisation strongly resemble those of C. varicauda Brunet, 1971 (see Brunet 1971). The epidermis is syncytial and �� 2 ��m thick, with cilia �� 2 ��m long. The basal membrane is �� �� of the epidermis height thick. Caudally, a girdle of adhesive papillae surrounds the body. The proboscis is about 1 / 8 to 1 / 10 of the body length long. The two small proboscis halves are 10���12 ��m long. Both are armed with a simple, 17���20 ��m long hook. Accessory hooks are lacking. The postrostral bulb is �� 2 / 3 of the length of the proboscis (�� 20 ��m). The pharynx is situated in the anterior part of the body. The wall of the prepharyngeal cavity is covered with spines. The pharynx is typically cylindrical and its length is about 1 / 5 of the body length (�� 140���220 ��m). The mouth is situated rostrally, at the ventral side, and is surrounded by circular muscles. The gonads are unpaired. The testis is situated in the anterior part of the body, ventrally from the pharynx. The ovary lies at about �� of the body length at the left-hand side of the body. The vitellarium is situated dorsally, and extends from just behind the pharynx up to the oviduct. The gonopore lies at 70 %, just behind the external opening of the vagina externa, and is surrounded by a weak sphincter. The common genital atrium is slender, tubular and proximally surrounded by a circular muscle layer. Two types of glands empty into the common genital atrium: eosinophilic glands and, more distally, basophilic glands. Distally from the opening of the basophilic glands, the common genital atrium is surrounded by longitudinal muscles. Two vasa deferentia leave the testis, and run caudally until halfway past the copulatory organ. Each of them then widens to form a seminal vesicle, which turns 180 �� and runs back in anterior direction. The seminal vesicles and the vasa deferentia are lined with an anucleated, membranous epithelium, and the seminal vesicles are surrounded by a circular muscle layer. Proximally, both vasa deferentia join to form the ejaculatory duct, which enters the copulatory bulb, and receives prostate secretion (conjuncta-type copulatory organ; terminology of Karling 1956 a). The prostate vesicle is surrounded by an inner circular and an outer longitudinal muscle layer. In live animals, the prostate vesicle and ejaculatory duct clearly showed a single winding. The prostate glands are eosinophilic, with the nuclei outside of the prostate vesicle. The prostate vesicle and the ejaculatory duct open into a slender cirrus. The cirrus and the prostate vesicle are surrounded by a muscular septum, which is lined with an inner circular and an outer longitudinal muscle layer (conjuncta-duplex type copulatory organ; terminology of Karling 1956 a). The cirrus is 52���76 ��m long, with a diameter of about 8 ��m. It is lined with a large number of rows of small, sclerotized teeth, which are all oriented in a distal direction. Just before the cirrus enters the atrium through its anterior wall, it receives a small, armed accessory cirrus, 12���17 ��m long and 3���4 ��m broad. The cirrus, the accessory cirrus and the common genital atrium are surrounded by a longitudinal muscle layer. The short oviduct receives the vitelloduct through its dorsal wall, and together they form the very short female duct. This female duct enters the common genital atrium a little caudally from the place where the male genital system enters. A circular muscle layer surrounds the female duct, the oviduct and the most distal part of the vitelloduct. The female duct is lined with an anucleated, membranous epithelium. Caudally from the ovary a large bursa occurs, which contains several compartments with sperm. The female bursa is connected to an external vagina, which is a relatively long duct, lined with a high, anucleated epithelium. Its proximal part is surrounded by circular muscles. This part also contains spermatozoa. The distal part of the vagina is surrounded by longitudinal muscles. The vaginal opening is surrounded by a strongly-developed sphincter. Within the dorso-anterior part of the bursa, three muscular sperm-containing compartments can be observed. From each of these compartments a sclerotized spermatic duct departs towards the ovary. In their middle parts these three ducts are wound around each other, so that they cannot be discerned separately. Near the ovary they diverge again, and enter the ovary as three separate ducts near to the place where the oviduct departs. The spermatic ducts are surrounded by a parenchymatous tissue, which is a continuation of the parenchymatous tissue of the bursa. A uterus is absent. Discussion. See discussion Cheliplana uruguayensis n.sp., Published as part of Steenkiste, Niels Van, Volonterio, Odile, Schockaert, Ernest & Artois, Tom, 2008, Marine Rhabdocoela (Platyhelminthes, Rhabditophora) from Uruguay, with the description of eight new species and two new genera, pp. 1-33 in Zootaxa 1914 on pages 10-12, DOI: 10.5281/zenodo.184571, {"references":["Brunet, M. (1971) Cheliplana varicauda n. sp., nouveau turbellarie calyptorhynque de la famille des Karkinorhynchidae. Annales de l'Universite de Provence, 45, 25 - 28.","Karling, T. G. (1956 a) Morphologisch-histologische Untersuchungen an den manlichen Atrialorganen der Kalyptorhynchia (Turbellaria). Arkiv for Zoologi, 9, 187 - 277."]}

Baicalellia forcipifera n.sp. (Figs. 7, 8 A) Locality. La Coronilla, Departamento de Rocha, Uruguay (33 ° 54 ’18.50”S, 53 ° 30 ’39.30”W). Beach and mouth of the canal near hotel Parque Océanico: sand covered by a thin green layer of organic material and sand with organic material near a small pool in open contact with the ocean (01/08/ 2004): type locality. Material. Observations on a live animal. Three whole mounts, one of which designated holotype (SMNH 7499), another one designated paratype (HU no. 410). Nine serially-sectioned specimens, of which seven designated paratypes (HU no. 411–417). Unfortunately one of the better whole mounts, originally intended to be designated as the holotype and shown in fig. 7 B (lower figure), was lost. Another whole mount was chosen as the holotype. Etymology. The species name refers to the pincers-shaped stylet. Forceps (Lat.): pincers. Ferre (Lat.): to carry. Description. The body length of the animal varies between 0.5–0.7 mm. The internal organisation does not differ from the other species of the taxon Baicalellia Nasonov, 1930 (see Nasonov 1930, 1932; Luther 1962; Ax 1995). The anteriorly-situated pharynx doliiformis lacks tentacle-like structures. The copulatory bulb is surrounded by a thick, inner, spirally-running to circular muscle layer and outer longitudinal muscles. The prostate vesicle is also surrounded by longitudinal muscles. Distal to the copulatory bulb, a pincers-shaped stylet is present. It consists of a common base from which two separate, curved arms depart. The longest of these arms is 44–49 µm long and hollow. It is filled with the prostate secretion that proximally enters the stylet. The shortest arm is 20–27 µm long and seems to be an accessory outgrowth of the longer arm's wall. From the base to the distal apex of the longest arm, the stylet measures 54–59 μm. The base of the stylet has a proximal rim and is connected to the copulatory bulb. The male atrium fits tightly around the stylet. Distally it opens into the common genital atrium. The bursa copulatrix is a sack-shaped protrusion of the common genital atrium and is filled with spermatozoa. It runs dorsally from the male atrium and has a very broad connection with the common atrium. In consequence, differentiation between the bursa copulatrix and the common atrium is not always clear. The bursa copulatrix and the male genital atrium are lined with a relatively high, anucleated epithelium and surrounded by a weaklydeveloped circular muscle layer. The gonopore is at about 75 % and surrounded by a sphincter. The female duct enters the common genital atrium through its caudal wall. At the place of entry, a strong sphincter is present. This female duct is relatively short and broad, lined with a high, nucleated epithelium and surrounded by a strongly-developed circular muscle layer. The lumen is filled with spermatozoa. Proximally, both oviducts and a bundle of eosinophilic glands enter the female duct. The oviducts are very short and lined with a membranous epithelium. Ventrally from the oviducts, a seminal bursa opens into the female duct through a sphincter. The seminal bursa is spherical to club-shaped and has a fairly long bursal stalk. It is lined with a membranous epithelium. The bursa contains sperm, which are thinner and less darkly-stained than the sperm found elsewhere in the animal. A uterus is absent. Discussion. This species can easily be placed within the taxon Baicalellia Nasonov, 1930, as it shows diagnostic characters of this taxon: paired gonads, with the testes rostrally connected to each other, and ovaries fused with vitellaria to form two ovovittelaria. Almost all of the 17 species of Baicalellia have a tubiform to funnel-shaped prostate stylet, which is straight or curved. Apart from Baicalellia forcipifera n.sp., only two other species have a stylet with a lateral outgrowth: B. canadensis Ax & Armonies, 1987 and B. anchoragensis Ax & Armonies, 1990. In B. anchoragensis the stylet is short and broad, and the outgrowth has a little spine of its own. In B. canadensis the stylet is somewhat longer and less sturdy, and the outgrowth is a simple, relatively short spine. In B. forcipifera n.sp. both the stylet and the outgrowth are long and very slender, giving it its typical pincer-like shape. Nasonov (1930) describes the seminal bursa as a seminal receptacle and a phagocytic organ that serves to resorb redundant sperm. Ax (1954, 2008), Luther (1918, 1921) and Marcus (1946) use the name seminal bursa, while Ax & Armonies (1990) keep to syncytial tissue. According to Nasonov (1930) the strongly-thickened, syncytial epithelial wall of this organ contains vacuoles with sperm in various degrees of disintegration. The existence of such vacuoles is confirmed by Ax (1954), Ax & Armonies (1990), Luther (1921), Marcus (1946) and Joffe & Selivanova (1988). In Baicalellia forcipifera n.sp. only a very thin epithelium without vacuoles was observed. However, the lumen of the seminal bursa contains disintegrating sperm. The base of this organ is surrounded by a sphincter. This has also been observed in nearly all species except for B. canadensis, B. evelinae Marcus, 1946 and B. groenlandica Ax, 1995. The opening and position of this organ in the genital system vary from species to species, as discussed by Ax & Armonies (1990) for B. posieti Nasonov, 1930, B. sewardensis, B. anchoragensis and B. brevituba (Luther, 1921) Nasonov, 1930. In the other species, the seminal bursa is always situated between, ventrally or dorsally from the ovovitellaria. In B. canadensis, a seminal bursa (indicated as seminal receptacle by Ax & Armonies 1987) was only observed as an appendage of the copulatory bursa. This makes the placement of this species within the genus Baicalellia uncertain (see Ax & Armonies 1987). In Baicalellia forcipifera n.sp. the female duct is clearly separated from the genital atrium by a stronglydeveloped sphincter. This is a somewhat unusual situation in Baicalellia, where the female duct is mostly very short, even considered part of the common genital atrium. Only Ax & Armonies (1987, 1990) use the term “female duct” as such, but in B. forcipifera n.sp. it is unusually long, even compared with that of B. canadensis, where it is also clearly separated from the common genital atrium by a strong sphincter. This feature, together with the construction of the seminal bursa and the form of the stylet, clearly shows that the material from Uruguay belongs to a new species. Diagnosis. Baicalellia forcipifera n.sp.: species of Baicalellia with a ± 54–59 μ m -long, slender stylet, carrying a ± 20–27 μ m -long, slender spine. Stylet and outgrowth together have the shape of pincers. Female duct long, clearly delimited, with a nucleated epithelium and surrounded by a strongly-developed, circular muscle layer. Seminal bursa without vacuoles and containing disintegrated sperm.

Djeziraia pardii Schockaert, 1971 Known distribution. Djezira (about 15 km south of Mogadiscio, Somalia) (Schockaert 1971). New localities in the Indian Ocean. McKenzie Point, Mombasa (Kenya): superficial layer of sand in a shallow pool on top of a rock in the lower eulittoral (25 /09/ 1991); same locality: on seagrass (Thalassia) from a very shallow tide-pool just before the obelisk a short distance past the Four Seasons Restaurant (27 /09/ 1991). Material. Type material and the material of the original description. Two whole mounts from Kenya, one from each locality. Remarks. For a detailed description we refer to the original description by Schockaert (1971) and the additions in Schockaert (1982). In the original description, the presence of a ���diverticulum��� on the ���bursal stalk��� (female duct type I) is mentioned. In fact, this diverticulum is the common oviduct connecting the bursal stalk with the seminal receptacle at the junction of the ovaries (see Artois & Schockaert 2001, 2005). The lengths of the stylet as measured on the new material (81 ��m and 82 ��m) are almost identical to that of the only whole mount from Somalia (paratype) (84 ��m)., Published as part of Artois, Tom J. & Tessens, Bart S., 2008, Polycystididae (Rhabditophora: Rhabdocoela: Kalyptorhynchia) from the Indian Ocean, with the description of twelve new species, pp. 1-27 in Zootaxa 1849 on page 7, DOI: 10.5281/zenodo.183373, {"references":["Schockaert, E. R. (1971) Turbellaria from Somalia I. Kalyptorhynchia (Part 1). Monitore Zoologico Italiano (N. S.), Suppl. 4, 101 - 122.","Schockaert, E. R. (1982) Turbellaria from Somalia II. Kalyptorhynchia (Part 2). Monitore Zoologico Italiano (N. S.), Suppl. 17, 81 - 96.","Artois, T. J. & Schockaert, E. R. (2001) Interstitial fauna of the Galapagos: Duplacrorhynchinae, Macrorhynchinae, Polycystidinae, Gyratricinae (Platyhelminthes Polycystididae). Tropical Zoology, 14, 63 - 85."]}

Cheliplana uruguayensis n.sp. (Fig. 5) Locality. La Coronilla, Departamento de Rocha, Uruguay (33 ° 54 ’18.50”S, 53 ° 30 ’39.30”W). Beach and mouth of the canal near hotel Parque Océanico: flat beach further away from the mouth of the canal, sand with organic material a couple of meters from a small intertidal pool (01/08/ 2004): type locality. Material. Observations on a live animal. Three whole mounts, one of which designated holotype (SMNH 7497), another one designated paratype (HU no. 406). Six serially-sectioned specimens, two of which designated paratypes (HU no. 407–408). Etymology. The species name refers to its occurrence in Uruguay. Description. The body length of the animal varies between 0.6–0.8 mm. Habitus and internal organisation as in Cheliplana triductibus n.sp., except for the construction of the genital system. From the testis two morphologically dissimilar vasa deferentia depart. One is of the normal construction; thin-walled and distally widening to a seminal vesicle, which is lined with a membranous, nucleated epithelium. The other vas deferens is enlarged and is surrounded by a layer of very thick, longitudinal muscles. It is 190–260 μm long. The seminal vesicle and the modified vas deferens join each other distally to form the ejaculatory duct, which enters the copulatory bulb. The copulatory organ is of the conjuncta-duplex type, as in the other species of Cheliplana de Beauchamp, 1927. The prostate vesicle is 120–170 μm long, with a diameter of ± 35 μm, and is surrounded by strongly-developed longitudinal muscles. The prostate secretion and the ejaculatory duct distally enter a short, tubular stylet. This stylet is ± 11 μm long. The male genital atrium is lined with a membranous epithelium and surrounded by a longitudinal muscle layer. In its distal half, it receives a bundle of basophilic glands. Distally it widens before entering the common genital atrium. This common genital atrium is very broad and relatively long. Proximally it receives some eosinophilic and basophilic glands. The epithelium is high and the common genital atrium is surrounded by longitudinal muscles over its entire length. Distally, it narrows again to broaden a second time just before it reaches the gonopore. This is situated at 80 % and surrounded by a sphincter. The ovary is situated dorsally at the left-hand side and joins the bursa. Proximally it is connected with the vitellarium to form an ovovitellarium. This vitellarium bends from the ovary to the ventral side and extends rostrally up to the level of the testis. The caudally-situated female bursa is connected to the ovary by a broad duct consisting of bursal tissue. A separate spermatic duct was not observed. The bursa contains numerous optically-clear vacuoles. An external vagina is connected to the bursa and has a thick, sclerotized wall. It widens to a spherical space just proximally from the vaginal opening. The vaginal opening is situated rostrally from the gonopore. At the place where the external vagina enters the bursa, a separate seminal receptacle is also connected to the bursa. This seminal receptacle is elliptical and is surrounded by circular muscles. Discussion. These two new species can easily be recognized as species of Karkinorhynchidae, as they have a proboscis provided with symmetrical hooks. In representatives of Diascorhynchidae Meixner, 1929, the only other schizorhynch taxon with representatives with armed probosces, the hooks are asymmetrical. A large number of diagnostic features makes it easy to place both new species within the taxon Cheliplaninae (see Karling 1983): presence of a postrostral bulb, presence of only one pair of hooks (also the case in some Karkinorhynchinae), absence of separate lateral glands, lack of eyes (also the case in very few species of Karkinorhynchinae), presence of a single girdle of adhesive papillae (two such girdles in almost all Karkinorhynchinae), anteriorly-situated pharynx mostly cylindrical, directed anteriorly and often with a long, spiny prepharyngeal cavity. By comparing the features of the two species discussed here with the diagnoses of the genera of the taxon Cheliplaninae, the Uruguayan species clearly belong to the genus Cheliplana because of the following features: proboscis hooks without denticles, soft fingerlike side pieces and a cylindrical pharynx with a long spinous cavity. They distinguish themselves from species of Baltoplana Karling, 1949 by the fact that Baltoplana has paired ovaries and testes, and from species of Cheliplanilla Meixner, 1938 because this taxon has crutch-shaped cuticular rods between the proboscis side pieces, proboscis hooks with two pairs of inside denticles, a blind seminal vesicle and an oviform pharynx with a short unarmed cavity (see Karling 1983). They also differ from Archipelagoplana triplocirro Noldt & Hoxhold, 1984 because this species lacks a long spinous pharynx cavity and because A. triplocirro has two small accessory cirri (see Noldt & Hoxhold 1984). Karling (1983) considered the number of testes as an unreliable generic character and by consequence placed all representatives of the genus Rhinipera Meixner, 1928 (one testis) within the genus Cheliplana (two testes), a view we follow here. Cheliplana triductibus n.sp. stands unique within the genus because of the combined presence of three sclerotized spermatic ducts and one smaller accessory cirrus. In C. hiemalis Brunet, 1968, C. pacifica Noldt & Hoxhold, 1984, C. piriformis Brunet, 1968, C. pusilla Brunet, 1968, C. schilkei Noldt, 1989 and C. targa (Marcus, 1952) Karling, 1983, there is only one sclerotized spermatic duct between the bursa copulatrix and the ovary (see Brunet 1968; Karling 1983; Noldt & Hoxhold 1984, Noldt 1989). C. varicauda Brunet, 1971 has a comparable female and male system to C. triductibus n.sp., but its three spermatic ducts are only slightly sclerotized and the muscular proximal parts contain a spherical nucleus. In the male system, C. varicauda lacks the smaller accessory cirrus. Also the extremely long caudal part, posterior to the genital system, is lacking in the new species (see Brunet 1971). Accessory cirri are also present in C. textilis Jouk & De Vocht, 1989, but they have two blind accessory cirri that are lined with small spines in the posterior part and even on one side (see Jouk & De Vocht 1989). Only very recently, Ax (2008) described a new species of Cheliplana from brackish water habitats along the French Atlantic coast and the Baltic Sea, with a very similar copulatory organ. This species, C. deverticula Ax, 2008, has also a winding prostate vesicle and ejaculatory duct, and a slender, armed cirrus (75 μm long) with a single small, armed accessory cirrus (17 μm long). However, nothing is known about the female system of this species. Awaiting more material of C. deverticula and a description of its female system, the Uruguayan specimens are provisionally placed within a new species. If the female system would prove to be identical, C. triductibus n.sp. should be synonymized with C. deverticula. Cheliplana uruguayensis n.sp. differs from all other species of Cheliplana by the presence of two different seminal vesicles, a character shared with the genus Cheliplanilla, although in the latter the modified seminal vesicle ends blindly. This new species mostly resembles C. targa. Similarities are found in the female system as well as in the male genital system: one testis situated ventrally from the pharynx; a seminal vesicle with a well-developed muscular wall; a very muscular prostate vesicle that distally ends in a short, tubular stylet, and a syncytial bursa containing vacuoles. In contrast to C. targa, which has only one seminal vesicle, C. uruguayensis n.sp. has two seminal vesicles. Moreover, C. uruguayensis n.sp. differs from C. targa by having a non-muscular vas deferens, eosinophilic and basophilic glands opening into the common genital atrium, and by lacking a slerotized spermatic duct. Diagnosis. Cheliplana triductibus n.sp.: species of Cheliplana with unpaired male and female gonads. Proboscis 30 μ m long and consisting of 11 μ m-long proboscis hooks, 19 μ m-long proboscis halves and a 20 μ m-long postrostral bulb. Without accessory denticles in the proboscis. Two seminal vesicles. Muscular prostate vesicle followed by a 64 μ m-long cirrus with uniform teeth (3–4 μ m long). Small, armed, lateral accessory cirrus with a length of 15 μ m at the distal end of the cirrus. Short female duct. Vagina externa connected with a syncytial bursa. Three cuticularized spermatic ducts and muscular ducts connect the ovary with the bursa. Diagnosis. Cheliplana uruguayensis n.sp.: species of Cheliplana with unpaired male and female gonads. Proboscis 23 μ m long, consisting of 8 μ m-long proboscis hooks, 16 μ m-long proboscis halves and a 23–25 μ m-long postrostral bulb. Accessory denticles absent in the proboscis. Two different seminal vesicles, of which one is a modified vas deferens surrounded by strongly-developed, longitudinal muscles. Both seminal vesicles are connected with the testis. Long, longitudinally muscular prostate vesicle (± 150 μ m long). Short tubular stylet (11 μ m long). Vagina externa with cuticularized wall connected with a syncytial bursa containing vacuoles. Elliptic seminal receptacle filled with spermatozoa.

Vauclusia multistriata n.sp. (Figs. 9 C, 10) Locality. La Coronilla, Departamento de Rocha, Uruguay (33 ° 54 ’18.50”S, 53 ° 30 ’39.30”W). Beach and mouth of the canal near hotel Parque Océanico: sand covered by a thin green layer of organic material and sand with organic material near a small pool in open contact with the ocean (01/08/ 2004): type locality. Material. Observations on one live animal. One whole mount, designated holotype (SMNH 7501). Two serially-sectioned specimens, of which one designated paratype (HU no. 363). Etymology. The species name refers to the many internal ridges of the stylet. Multus (Lat.): many. Striatus (Lat.): striated. Description. Slender, 0.5 mm long animal. Eyes absent. The habitus is characterized by division of the body into three zones: a slender, rostral part where rhabdite glands occur (± 1 / 5 of the body length), a middle part where all organs are situated (± 3 / 5 of the body length), and a caudal part, which consists of a clearlydelimited, small tail with an epidermis containing many more rhabdites than the rest of the body (± 1 / 5 of the body length). The ciliated epidermis is cellular and has a height of about 3 μm. The basal membrane is very thin. The cilia measure about 3 μm. In the rostral part of the body, two different kinds of rhabdite glands occur. The first type produces long, lancet-shaped, basophilic rhabdites with a length of 8–10 μm, the other type produces smaller, oval, eosinophilic rhabdites with a length of about 2–3 μm. Both kinds of glands extend from above the brain to the rostral body end, where they empty. Caudally from the pharynx, dispersed eosinophilic rhabdite glands occur, which empty in the epidermis. The largest concentration of these rhabdite glands is situated behind the genital system in the caudal body part. The length of the oval, eosinophilic rhabdites that are secreted by these glands varies between 2–4 μm. The epidermis of the caudal region is completely filled with these rhabdites. The mouth is situated at about 40 %. The organisation and structure of the pharynx is identical with that of Vauclusia conica Willems et al., 2004 (see Willems et al. 2004). The gonads are paired. The two round testes are situated ventrally, just in front of the pharynx and at both sides of the body. The seminal vesicles are rather small and have an anucleated, membranous epithelium. They are not surrounded by muscle layers. When entering the prostate vesicle, both vasa deferentia join to form a ductus ejaculatorius, which runs centrally through the prostate vesicle. Centrally, this prostate vesicle contains coarse-grained, eosinophilic glands, which are surrounded by fine-grained eosinophilic glands. All glands together take up about half of the total volume of the prostate vesicle. Both the fine-grained and coarse-grained eosinophilic glands have extracapsular nuclei-containing parts, and penetrate the prostate vesicle together with the ejaculatory duct. The prostate vesicle is surrounded by thick, inner circular muscles and outer longitudinal muscles. Distally, the prostate vesicle is connected with a conical and thin-walled stylet. This stylet has a length of 45 μm. Proximally, it is 21 μm broad at its broadest, distally up to 4 μm. The inner side of this stylet is ornamented with a large number of ridges that are oriented in three different directions. For the first 17 μm, the ridges run lengthways, the next 7 μm they run transversely and the last 21 μm again lengthways. The male genital atrium is surrounded by circular muscles and is lined with an anucleated, membranous epithelium, as is the common genital atrium. The common gonopore is situated at about 70 %. The ovaries lie caudally from the gonopore and together with the more rostrally-situated vitellaria, they form long ovovitellaria, which stretch dorsolaterally at both sides beyond the testes. The oviducts are very short, and open in the long, very muscular female duct, which caudally enters the common genital atrium. It is lined with a high, anucleated epithelium and surrounded by a circular muscle layer, which is very well developed in the proximal half. Distally, it is slightly swollen and some nuclei are seen in the somewhat higher epithelium of the transition zone between the female duct and the common genital atrium. Moreover, the distal half of the female duct is surrounded by a peripheral, longitudinal muscle layer. The female bursa is spherical and lined with a nucleated, membranous epithelium. It contains a great deal of sperm in the lumen. A broad bursal stalk connects the bursa with the proximal end of the female duct. Its epithelium is very high and shows many glands. Where it enters the bursa, a sphincter is present. In the proximal part of the female duct, sperm and a glandular secretion were observed. Eosinophilic and basophilic female glands enter this part of the female duct. A uterus is lacking. Discussion. The species described here can easily be placed in the taxon Vau c lu s ia Willems et al., 2004 because of the combined presence of the following characters (see Willems et al. 2004): pharynx in the middle of the body, paired testes and seminal vesicles, spherical prostate vesicle and two types of glandular secretions, conical stylet with different internal ridges, a long male atrium, paired ovovitellaria, a long muscular female duct with a swollen distal part, and the presence of a female bursa and female glands. The construction of the pharynx and the position of the testes are comparable with those of V. conica Willems et al., 2004, the only other representative of the taxon, although in V. multistriata n.sp. the pharynx is situated somewhat more anteriorly. A first important difference between the two species occurs in the size of the stylet and the pattern of its ridges. Although Vauclusia conica is almost three times as long as V. multistriata n.sp., its stylet is smaller than the stylet of V. multistriata n.sp. The exact structure of the stylet in V. conica could not be ascertained, but it apparently has about eight spirally-running and striated ridges (Willems et al. 2004). In contrast, the stylet of V. multistriata n.sp. has many ridges, transverse as well as longitudinal. Secondly, the prostate glands of V. c o n i c a take up the full volume of the prostate vesicle, which is not the case in V. multistriata n.sp. Another difference is the presence of a bursal stalk with a glandular epithelium between the bursa and the female duct in V. multistriata n.sp. In V. conica, the bursa links up directly with the proximal part of the female duct through a sphincter. Finally, V. conica has an inversion of the muscle layer in the transition zone between the common genital atrium and the male atrium. Some of the features that are unique to Vauclusia conica were mentioned in the original diagnosis of this genus by Willems et al. (2004), but now these features should be removed from this diagnosis. Amended diagnosis (after Willems et al. 2004). Va u cl u si a: Promesostomidae with the pharynx in the middle of the body. Paired testes and seminal vesicles. Spherical prostate vesicle with two types of secretions. Conical stylet with several internal ridges. Paired ovovitellaria. Very long, muscular female duct. Distal part of the female duct swollen. Female bursa and female glands present. Male atrium long. Diagnosis. Vauclusia multistriata n.sp.: species of Va uc lu s ia with a 45 μ m-long stylet with many internal ridges that run lengthways proximally and distally, and transversely in between. Prostate glands only fill a portion of the prostate vesicle. Duct with glandular epithelium between the bursa and the female duct.

Alcha evelinae Marcus, 1949 Known distribution. Widespread in tropical and subtropical coastal zones: Brazil (Marcus 1949); California (USA) (Karling & Schockaert 1977); Mombasa (Kenya): McKenzie Point and English Point, at 6 m depth on Thalassia hemprichii, partly covered by the epiphyte Syringodium isoetifolium (Jouk & De Vocht 1989). New localities in the Indian Ocean. McKenzie Point, Mombasa (Kenya) on Thalassia from some shallow tide pools with sandy sediment at the stairs near the Four Seasons Hotel (mid-eulittoral) (30 /09/ 1991). New localities outside the Indian Ocean. Mazatlan (Mexico), algae from a tide pool near some rocks near hotel Valentino (04/ 12 / 1996). Material. The lectotype (a sectioned specimen) and two paralectotypes (two whole mounts) (SMNH). One whole mount and three sectioned specimens from California (SMNH). All the material of Jouk & De Vocht (1989) (more than 25 whole mounted specimens). Studies on live animals, one whole mount and one sagitally sectioned specimen from the new locality in Kenya. One whole mount from Mexico. Remarks. Habitus and internal organisation largely correspond with the description by Karling & Schockaert (1977). Some animals were more uniformly blue, without showing clear separated bands of pigment. In the newly found specimens from Kenya and Mexico, the length of the complicated prostate stylet type III is 42 ��m and 35 ��m respectively, which correspond with the range found in literature: 33���53 ��m (Marcus 1949; Karling & Schockaert 1977; Jouk & De Vocht 1989). We observed a large amount of sperm stored in the male atrium, which was not mentioned in earlier descriptions. The female system is more or less as described by Karling & Schockaert (1977): a strong muscular female duct type I proximally splits into two enlarged sperm containing vesicles. Distally from these sperm-containing vesicles, the two oviducts enter the female duct. We did not observe the insemination ducts (see Karling & Schockaert 1977; Artois & Schockaert 2005). However, in the Californian specimens these insemination ducts are clearly present. These structures are very delicate and difficult to see, and we presume their presence in the Kenyan specimen., Published as part of Artois, Tom J. & Tessens, Bart S., 2008, Polycystididae (Rhabditophora: Rhabdocoela: Kalyptorhynchia) from the Indian Ocean, with the description of twelve new species, pp. 1-27 in Zootaxa 1849 on page 4, DOI: 10.5281/zenodo.183373, {"references":["Marcus, E. (1949) Turbellaria Brazileiros (7). Boletins da Faculdade de Filosofia, Ciencias e Letras, Universidade de S. Paulo, 14, 7 - 155.","Karling, T. G. & Schockaert, E. R. (1977) Anatomy and systematics of some Polycystididae (Turbellaria, Kalyptorhynchia) from the Pacific and S. Atlantic. Zoologica Scripta, 6, 5 - 19.","Jouk, P. E. H. & De Vocht, A. J. - P. (1989) Kalyptorhynchia (Plathelminthes Rhabdocoela) from the Kenyan coast, with descriptions of four new species. Tropical Zoology, 2, 145 - 157."]}