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Schizochilus espinosai sp. n. (Fig. 12 A–B, 15E) http://zoobank.org/ urn:lsid:zoobank.org:act: 2CF67117-9665-4779-96D4-2B0A4272D392 Material. One specimen studied alive and whole mounted, designated holotype (FMNH https://id.luomus.fi/ KV.617), collected in Bueycabón (type locality) (February 21, 2018), sublittoral, fine-grained sand with organic matter, 0.5 m depth, salinity 33 ‰. Etymology. Species dedicated to Prof. Em. Dr. José Espinosa Sáez (Instituto de Ciencias del Mar, La Habana, Cuba), specialist in ecology and taxonomy of molluscs, and awarded with the National Award of Marine Sciences of Cuba (2018). Diagnosis. Species of Schizochilus with a spiny cirrus 71 μm long; spines talon-shaped, about 3 μm long. A 52-μm-long, needle-shaped stylet runs centrally through the cirrus. Copulatory bulb distally forming a 12-μm-long cap. Description. Animal 0.9 mm long, measured on the whole mount, translucent, without eyes. Proboscis lips (Fig. 12A: pr) 77–92 μm long (x = 85 μm; n = 2), with a pair of caudal glands. Pharynx (Fig. 12A: ph) 72 μm in diameter, located at 70%. Four testes (Fig. 12A: t) lie in a row rostrally from the pharynx, fused two by two into two pairs. Copulatory bulb (Fig. 12A: cb, 15E) 77 μm long, comprising the prostate vesicle and the spiny cirrus. The cirrus is 71 μm long and 6 μm wide, measured over its midlength. The spines are talon-shaped and about 2–3 μm long (x = 3 μm; n = 2). A 52-µm-long stylet (Fig. 12B) runs centrally through the cirrus. It is 6 μm wide proximally, needle shaped, and tapers to a distal sharp point. The copulatory bulb forms a distal sclerotized cap of 12 μm long and 9 μm wide at the widest point. As such, it surrounds the cirrus for 23% of the latter’s length. The common gonopore (Fig. 12A: cg) opens at 90%. A pair of vitellaria (Fig. 12A: vi) extend between the brain (Fig. 12A: br) and the copulatory bulb, one vitellarium at each side of the body. A bursa (Fig. 12A: b) and ovary (Fig. 12A: ov) are located in the caudal body end. The uterus (Fig. 12A: ut) is directed forwards, situated beside the copulatory bulb.

Kalyptorhynchia Graff, 1905 Schizorhynchia Meixner, 1928, Published as part of Diez, Yander L., Reygel, Patrick & Artois, Tom, 2019, Schizorhynchia (Platyhelminthes, Rhabdocoela) from eastern Cuba, with the description of fifteen new species, pp. 1-30 in Zootaxa 4646 (1) on page 3, DOI: 10.11646/zootaxa.4646.1.1, http://zenodo.org/record/3346255, {"references":["Graff, L. v. (1905) Marine Turbellarien Orotavas und der Kusten Europas. Zeitschrift fur wissenschaftliche Zoologie, 83, 68 - 148.","Meixner, J. (1928) Aberrante Kalyptorhynchia (Turbellaria: Rhabdocoela) aus dem Sande der Kieler Bucht. Zoologischer Anzeiger, 77, 229 - 253."]}

Carcharodorhynchus flavidus Brunet, 1967 (Fig. 7) Known distribution. Several localities in the Mediterranean: France (Brunet 1967); several localities in Sardinia (Italy) (Gobert et al. 2017). Lanzarote (Canary Islands) (Gobert et al. 2017). Possibly North Carolina, United States (Whitson et al. 2011). Material and distribution in Cuba. Three specimens studied alive and whole mounted (HU X.1.08��� X.1.10), collected in Siboney (September 4, 2016; December 14, 2017), sublittoral, fine-grained sand with organic matter, 0.7���2 m depth, salinity 32���35 ���. Remarks. The live animals from Cuba are about 1.5���2 mm long, yellowish, without eyes. There is a pale belt near the posterior body end, corresponding to the single adhesive girdle. Proboscis (Fig. 7A: pr, 7B���C) symmetric to lightly asymmetric; largest lip 126���130 ��m long (n = 2) and the smallest one 118���119 ��m long (n = 2). Proboscis with paired fields of shark-tooth-shaped denticles situated along each proboscis lip, separated by a characteristic ���basal gap��� (see Brunet, 1967; Schilke 1970a; Whitson et al. 2011; Gobert et al. 2017). In the basal half of the toothed belts, the denticles are 1���2 ��m long (x = 1 ��m; n = 23) and are more or less ordered in three or four rows; in the distal half the denticles appear a bit larger 1���2 ��m long (x = 2 ��m; n = 12) and are ordered in two rows. In live animals, polygonal glands were observed in the internal surface of the lips (Fig. 7B: prg); the largest ones arranged in two rows on the central longitudinal axis of each lip. These larger glands are accompanied by smaller glands. None of these glands are observable on the whole mounts. Pharynx (Fig. 7A: ph) located at 50%, being about 7% of the body length in live animals. Three pairs of testes (Fig. 7A: t) are arranged in two rows in front of the pharynx. Copulatory bulb (Fig. 7D) 63���119 ��m long (x = 92 ��m; n = 3); it comprises the prostate vesicle and the spiny cirrus. Prostate vesicle (Fig. 7D: pv) 67���87 ��m long (x = 77 ��m; n = 2). Spiny cirrus (Fig. 7D: ci) 26���35 ��m long (x = 32 ��m; n = 3), proximally 7���12 ��m wide (x = 9 ��m; n = 3) and distally 17���19 ��m wide (x = 18 ��m; n = 3)., Published as part of Diez, Yander L., Reygel, Patrick & Artois, Tom, 2019, Schizorhynchia (Platyhelminthes, Rhabdocoela) from eastern Cuba, with the description of fifteen new species, pp. 1-30 in Zootaxa 4646 (1) on page 13, DOI: 10.11646/zootaxa.4646.1.1, http://zenodo.org/record/3346255, {"references":["Brunet, M. (1967) Turbellaries schizorhynques de la region de Marseille. Sur Carcharodorhynchus subterraneus Meixner et Carcharodorhynchus flavidus nov. sp. Bulletin de la Societe Zoologique de France, 92, 143 - 152.","Gobert, S., Reygel, P. & Artois, T. (2017) Schizorhynchia (Platyhelminthes Rhabdocoela) of Lanzarote (Canary Islands), with the description of eight new species. Marine Biodiversity, 1 - 19. [published online] https: // doi. org / 10.1007 / s 12526 - 017 - 0736 - x","Whitson, A., Smith III, J. P. S. & Litvaitis, M. K. (2011) Lehardyia alleithoros, sp. n. (Turbellaria, Kalyptorhynchia) from the Coast of North Carolina, USA. Southeastern Naturalist, 10 (2), 221 - 232. https: // doi. org / 10.1656 / 058.010.0203","Schilke, K. (1970 a) Kalyptorhynchia (Turbellaria) aus dem Eulitoral der deutschen Nordseekuste. Helgolander wissenschaftliche Meeresuntersuchungen, 21, 143 - 265. https: // doi. org / 10.1007 / BF 01630522"]}

Cheliplana gibarenha sp. n. (Fig. 2) http://zoobank.org/ urn:lsid:zoobank.org:act: 9DDAFE63-D0D3-4B1E-A7B6-B6099BF61011 Material. One specimen studied alive and whole mounted, designated holotype (FMNH https://id.luomus.fi/ KV.608), collected in Bah��a de Gibara (type locality) (March 26, 2017), sublittoral, fine-grained sand, 1 m depth, salinity 35 ���. Etymology. The epithet refers to the name given to the people that live in Gibara, where the type locality is situated. Diagnosis. Species of Cheliplana with the proboscis hooks 14 ��m long, curved, and the muscular hook supports 5 ��m long. A single seminal vesicle located in the caudal end of the body. Seminal vesicle and copulatory bulb directed forward. Cirrus 140 ��m long and 4 ��m wide distally, with the distal 13-��m-long portion (the cirrus) armed with fine spines about 0.5 ��m long. Description. Animal 0.8 mm long, measured on the whole mount, translucent, without eyes. Proboscis (Fig. 2A: pr, 2B) with hooks (Fig. 2B: h) curved, 14 ��m long; muscular hook supports (Fig. 2B: ms) 5 ��m long. Spiny prepharyngeal cavity (Fig. 2A: pph) slightly longer than the pharynx. Mouth (Fig. 2A: m) opens just caudally from the postrostral bulb (Fig. 2A: pb). Testis (Fig. 2A: t) located laterally from the pharynx, connected to the single seminal vesicle by a very long vas deferens. Seminal vesicle (Fig. 2A & 2 C���D: sv) located in the caudal body end. Seminal vesicle, including the seminal duct, 184 ��m long and 28 ��m wide at its widest point, with the seminal duct directed forwards. Copulatory bulb (Fig. 2 C���D) comprising the prostate vesicle and a cirrus, directed forward. Prostate vesicle (Fig. 2A & 2 C���D: pv) long-drawn. Cirrus (Fig. 2A & 2 C���D: ci) 140 ��m long and 4 ��m wide distally, with the distal 13-��m-long portion armed with small and fine spines (Fig. 2D: sp), about 0.5 ��m long. Distal part of the copulatory bulb, surrounding the spiny cirrus, marked by a strong sphincter (Fig. 2D: sph). Kidney-shaped ovary (Fig. 2A: ov) located at the level of the connection between the seminal vesicle and the prostate vesicle; it has the oocytes in a row, diminishing in diameter from the most distal to the most proximal end of the ovary. Bursa (Fig. 2A: b) located at the caudal end of the body; it seems to be bipartite and opens caudally into the vagina., Published as part of Diez, Yander L., Reygel, Patrick & Artois, Tom, 2019, Schizorhynchia (Platyhelminthes, Rhabdocoela) from eastern Cuba, with the description of fifteen new species, pp. 1-30 in Zootaxa 4646 (1) on page 4, DOI: 10.11646/zootaxa.4646.1.1, http://zenodo.org/record/3346255

Carcharodorhynchus papillaris sp. n. (Fig. 9) http://zoobank.org/ urn:lsid:zoobank.org:act: 01734072-BF6B-4DAD-98DD-C4BD54A2B471 Material. One specimen studied alive and whole mounted, designated holotype (FMNH https://id.luomus.fi/ KV.614), collected in Bueycab��n (type locality) (May 25, 2018), sublittoral, fine-grained sand with organic matter, 0.5 m depth, salinity 35 ���. Etymology. The epithet refers to the fact that the copulatory bulb ends in an unarmed papilla. Diagnosis. Species of Carcharodorhynchus with symmetric proboscis, lips 145 ��m long. The belts of denticles show a ���basal gap���; denticles shark-tooth shaped, 0.9 ��m long in the basal half of the belts and 3 ��m long in the distal half. A single seminal vesicle opens into the copulatory bulb. Copulatory bulb 102 ��m long and 29 ��m at the widest point, without hard structures, distally ending in a muscular penis papilla. Description. Live animal about 2 mm long, yellowish, without eyes. Proximal end of the body uncoloured. There is a pale belt near the posterior body end, corresponding to the single adhesive girdle. Proboscis symmetric, 145 ��m long. Proboscis (Fig. 9 A���B: pr, 9C) with paired fields of shark-tooth-shaped denticles on each proboscis lip. Toothed belts from both lips separated by a ���basal gap���. In the basal half of the toothed belts, the denticles are 0.6���1 ��m long (x = 0.9 ��m; n = 20) and are ordered in five to six rows. In the distal half the teeth are 3���4 ��m long (x = 3 ��m; n = 26) and are ordered in two to three rows. In live animals, polygonal glands are present on the internal surface of the lips. The largest of the glands are arranged into two rows following the central longitudinal axis of each lip. At both sides of the large glands, smaller glands can be observed. These glands are not observable on the whole mounts. Pharynx (Fig. 9A: ph) 95 ��m in diameter, located at 75%. A pair of testes is located rostrally from the pharynx. The vasa deferentia (Fig. 9F: vad) open separately into a single seminal vesicle (Fig. 9E: sv), which itself opens proximally into the copulatory bulb. Copulatory bulb (Fig. 9A: cb, 9D���F) 102 ��m long and 29 ��m at the widest point, without hard structures, ending in a muscular papilla. The prostate vesicle is short and rounded. Two types of prostate secretions were observed in the prostate vesicle of the live animal (Fig. 9 D���E: pv): in the proximal third a fine-grained secretion and in the middle third a coarsegrained secretion. Distal third of the copulatory bulb muscular, forming a penis papilla (Fig. 9 D���F: pp). Paired vitellaria extend between the brain (Fig. 9A: br) and the copulatory bulb. Ovaries and bursa located caudally from the common gonopore., Published as part of Diez, Yander L., Reygel, Patrick & Artois, Tom, 2019, Schizorhynchia (Platyhelminthes, Rhabdocoela) from eastern Cuba, with the description of fifteen new species, pp. 1-30 in Zootaxa 4646 (1) on page 15, DOI: 10.11646/zootaxa.4646.1.1, http://zenodo.org/record/3346255

Cheliplana asica Marcus, 1952 Known distribution. Caraguatatuba, San Sebasti��n and Canan��a, S��o Paulo, Brazil (Marcus 1952). Material and distribution in Cuba. One specimen studied alive and whole mounted (HU IX.4.42), collected in Bah��a de Gibara (March 26, 2017), intertidal, upper 20 cm of the fine-grained sand, salinity 35 ���. Remarks. Our specimen is 1.4 mm long, measured on the whole mount, translucent, without eyes. Proboscis hooks curved, 13 ��m long; muscular hook supports 9 ��m long. A single testis located caudally from the pharynx. Testis connected to two globular seminal vesicles, 27 ��m long. Copulatory bulb encloses the prostate vesicle and the unarmed cirrus. Cirrus 170 ��m long. Prostate vesicle 38 ��m long and 23 ��m at the widest point. Ovary rounded and located aside from the copulatory bulb. Globular bursa located at the level of the common gonopore. Bursa connected to the common atrium, and opens externally through a duct into the vagina, at the caudal end of the body., Published as part of Diez, Yander L., Reygel, Patrick & Artois, Tom, 2019, Schizorhynchia (Platyhelminthes, Rhabdocoela) from eastern Cuba, with the description of fifteen new species, pp. 1-30 in Zootaxa 4646 (1) on page 3, DOI: 10.11646/zootaxa.4646.1.1, http://zenodo.org/record/3346255, {"references":["Marcus, E. (1952) Turbellaria Brasileiros (10). Boletins da Faculdade de Filosofia, Ciencias e Letras, Universidade de Sao Paulo, 17, 5 - 187. https: // doi. org / 10.11606 / issn. 2526 - 4877. bsffclzoologia. 1952.125189"]}

Typhlopolycystis errata Artois and Schockaert, n. sp. (Fig. 14) Typhlopolycystis n.sp. in Tessens et al. 2014 Diagnosis. Colourless species of Typhlopolycystis, about 1 mm long with two small eyes and a proboscis of 1/4 of the body length. The prostate stylet is a broad curved gutter, 46 ��m with rounded ���lips���, slightly thickened at the concave side and at the proximal rims. The proximal diameter is 25 ��m. The curved accessory stylet is 107 ��m with a proximal ���head��� of 21 ��m and a sharp terminal end. Both stylets are not attached to each other. There is no clear accessory glandular reservoir. Genbank accession code: KJ887476 and KJ887545 Occurrence. Italy: Costa Paradiso, (Sardinia), Grotta Niedda, N41��03'08.84" W8��56'15.71", very coarsegrained sediment, shell gravel and pieces of coral, 32 m deep (type locality) (by Artois & Moons, 0 1 September 2010). Material examined. Observations on living animals and micrographs of the living animals. One whole mount (holotype SMNH nr 8914). Etymology. The species name refers to high similarity of hard parts with those of T. sarda n. sp. for which it was mistaken in the field; they occurred in the same sample. Errare (Lat.): to make a mistake. Additional data. T. sarda n. sp. and T. errata n. sp. are very similar in many aspects: size (1 mm or less), colourless, the proboscis of 1/4 of body length, a large seminal vesicle and no apparent accessory secretion reservoir. Whether this secretion reservoir is indeed completely lacking, should be confirmed on sections. The bundle of glands that opens in the genital atrium should be confirmed for both species as well. The copulatory organ is very similar in both species and the most striking similarity is the fact that the prostate stylet and the accessory stylet are not attached to each other. But there are clear differences in the hard parts: the prostate stylet of T. errata n. sp. is more slender than in T. sarda n. sp. and obviously larger. The accessory stylet is much longer than in the other species, with a very sharp end but with a relatively much smaller ���head���., Published as part of Schockaert, Ernest R., Moons, Patricia, Janssen, Toon, Tessens, Bart S., Reygel, Patrick C., Revis, Nathalie, Jouk, Philippe E. H., Willems, Wim R. & Artois, Tom J., 2019, On the genus Typhlopolycystis Karling, 1956 (Platyhelminthes, Kalyptorhynchia, Polycystididae), with data on the five known species and the description of eleven new species, pp. 81-104 in Zootaxa 4603 (1) on page 99, DOI: 10.11646/zootaxa.4603.1.4, http://zenodo.org/record/2673305, {"references":["Tessens, B., Janssen, T. & Artois, T. (2014) Molecular phylogeny of Kalyptorhynchia (Rhabdocoela, Platyhelminthes) inferred from ribosomal sequence data. Zoologica Scripta, 43, 519 - 530. https: // doi. org / 10.1111 / zsc. 12066"]}

Typhlopolycystis sarda Artois, Moons and Schockaert, n. sp. (Fig. 13) Diagnosis. Colourless species of Typhlopolycystis, about 1 mm long with eyes and a proboscis of 1/4 of the body length. The prostate stylet is a broad curved gutter with rounded “lips”, slightly thickened at the concave side and at the proximal rims. It is 30–40 µm long (40 µm in the holotype); proximal width is 21–26 µm. One of the “lips” is clearly narrower than the other one. The curved accessory stylet of 38–55 µm (55 µm in the holotype) has a proximal “head” of 15–23 µm and a blunt terminal end. Both stylets are not attached to each other. There is no clear accessory glandular reservoir. Occurrence. Italy: Costa Paradiso, (Sardinia), Grotta Niedda, N41°03'08.84" W8°56'15.71", very coarse sediment, shell gravel and pieces of coral, 32 m deep (by Artois & Moons, 0 1 September 2010) (Type Locality). France: Cerbère, Les Chambres, sand patch in seagrass bed, coarse sand mixed with shell grit, 13.7 m deep, 42°26’32.7”N, 3°10’20.4”E (by Revis & Jouk, 0 4 August 2014); Cap Peyrefitte, sand bottom, coarse sand with shell debris and silt, 21 m deep, 42°27’24.8”N, 3°10’19.7E (by Revis & Jouk, 16 July 2012). Spain: Portbou (Catalonia), Punta del Claper, clean sand mixed with shell grit, 20 m deep, 42°25’31.9”N, 3°10’15.2”E (by Revis & Jouk, 30 July 2011); Isle of Lanzarote (Canary Islands), Punta Jameos del Agua, medium, clean sand with Caulerpa, 38 m deep (29°9'25.10"N, 13°25'37.89"W, by Artois and Jansen, 15 October 2011). Material examined. Observations on living animals, micrographs of the living animals from most localities, including the type locality. Three whole mounts from Sardinia (one of them the holotype, SMNH nr. 8913 and two syntypes HU nrs III.2.05–06). Three whole mounts from Cerbère (HU nrs III.2.07–09), two whole mounts from Portbou (HU nrs III.2.10–11) and two whole mounts from Lanzarote (HU nrs III.2.12–13). Etymology. Species name refers to the type locality. Sardus (Lat.): Sardinian. Additional data. In most whole mounts, both stylets are detached from each other, as illustrated in the micrograph of the copulatory organ in the live animal (Fig. 13E 3). The prostate stylet has two pointed corners proximally, one at each “half”. The accessory stylet is about one and a half time longer than the prostate stylet. The “head” of the accessory stylet is relatively long, 40–60% of the accessory stylet itself. The seminal vesicle is very large and no accessory glandular reservoir was seen, but it may be very small and inconspicuous, lying between the prostate glands. There is a large bundle of glands ending in the genital atrium. For more comments see below.

Typhlopolycystis limicola Schilke, 1970 Species inquirenda Diagnosis. Gray and opaque species of Typhlopolycystis with eyes, 0.8 mm long. The proboscis is 1/5 of the body length (see fig. 5 of Schilke, 1970). The prostate stylet and the accessory stylet are proximally attached to a ���very thin membranous��� ring of 62 ��m (measures taken on Schilke���s fig. 5). The prostate stylet in the form of ���a sickle��� is 35 ��m long (45 ��m according to Schilke). The accessory stylet is 60 ��m long with a sharp bent end. The seminal receptacle has the chilli pepper shape. Occurrence. Mid-littoral sandy beaches on the Island of Sylt, Germany. Material examined. None. The species has been described only on living animals. Additional data. As said earlier, Schockaert & Karling (1975) consider T. limicola Schilke, 1970 as a synonym of T. mediterranea. Schilke (1960) claims that the proximal ring in T. limicola is more delicate than in T. mediterranea, and that it has a sharper accessory stylet. If the general organisation in fig. 5 of Schilke is correct, the proboscis seems to be only 1/5 to 1/6 of the body length, while it is up to 1/ 3 in T. mediterranea. On the other hand, the measurements of the copulatory organ fall in the range of variation seen in T. mediterranea. So, for the time being, and as long as no new material is available from Sylt, we prefer to consider T. limicola as a species inquirenda., Published as part of Schockaert, Ernest R., Moons, Patricia, Janssen, Toon, Tessens, Bart S., Reygel, Patrick C., Revis, Nathalie, Jouk, Philippe E. H., Willems, Wim R. & Artois, Tom J., 2019, On the genus Typhlopolycystis Karling, 1956 (Platyhelminthes, Kalyptorhynchia, Polycystididae), with data on the five known species and the description of eleven new species, pp. 81-104 in Zootaxa 4603 (1) on page 100, DOI: 10.11646/zootaxa.4603.1.4, http://zenodo.org/record/2673305, {"references":["Schilke, K. (1970) Kalyptorhynchia (Turbellaria) aus dem Eulitoral der Deutschen Nordseekuste. Helgolander wissenschaftliche Meeresuntersuchungen, 21, 143 - 265. https: // doi. org / 10.1007 / bf 01630522","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. https: // doi. org / 10.1111 / j. 1463 - 6409.1975. tb 00725. x"]}

Typhlopolycystis riegeri n. sp. Artois & Schockaert. (Figs 12 A–C) Diagnosis. Colourless species of Typhlopolycystis of about 1 mm with a proboscis 1/6 to 1/5 of the body length and with eyes. The prostate stylet is rather broad (18 and 14 µm, 14 µm in the holotype), 99 (in the holotype) and 104 µm long, almost straight in the proximal 2/3 of its length, then bent over 90° and tapering to a blunt end. The accessory stylet starts at the convex end of the main stylet; after a short turn over 180° it is straight and pointed, 104 and 91 µm long. The proximal diameter is 26–29 µm. The prostate vesicle seems reduced. The seminal receptacle is pear-shaped. Occurrence. Tanzania: Mbweni (Zanzibar Island), beach behind the Mbweni Ruins Hotel, south of the creek, in a higher part of the tidal sand flat, with relatively coarse sand (by Artois & Schockaert, 11 August 1995; Type Locality). Same locality but north of the creek, in a small pool with sea-grass (Thallasia spec.), all at low tide. Material examined. A whole mount from the type locality, indicated as holotype. (SMNH nr 8917). A second whole mount from the second habitat (HU nr III.1.47). Etymology. We dedicate this species in honour and friendship of the late Prof. Dr. R. Rieger (Innsbruck, Austria).

Typhlopolycystis australiensis Reygel, Schockaert & Artois n. sp. (Figs 12 H–J) Diagnosis. Yellowish-brown species of Typhlopolycystis, around 1 mm long with a proboscis 1/5 of the body length and with eyes. The prostate stylet is 63 µm long and 20 µm broad, regularly curved with a blunt end. The accessory stylet starts at the convex end of the main stylet; it is 73 µm long with the same curvature as the main stylet. A prostate vesicle was not observed; the seminal vesicle and the accessory secretion reservoir are relatively small. The seminal receptacle is pear-shaped. Occurrence. Australia: Adelaide (South Australia), Port Lincoln, Boston Bay, in sand extracted from between the roots of Possidonia australis from just under the low water line (by Reygel & Willems, 28 November 2010). Material observed. One animal studied alive and mounted as the holotype (QldM nr G235804). Etymology. Species named after the locality where it was found.

Subfamily Typhlopolycystidinae Evdonin, 1977 Type genus: Typhlopolycystis Karling 1956 (by original designation). Diagnosis (emended by Artois & Schockaert (2000) and slightly adapted): Polycystididae with a proboscis of 1/8 to 1/3 of body length. Cone retractors parallel to each other. Proboscis with a thick, inner circular muscle layer. Four pairs of proboscis retractors and one pair of integument retractors. Two pairs of strong dilators on the proboscis cavity. Gonads unpaired (vitellaria may be paired). Stylet a simple plate, a gutter or a tube. Accessory stylet, if present, tubiform, proximally connected to the stylet. Accessory glandular organ mostly present. Prostate vesicle (if present) completely or partly enclosed by the proximal part of the male atrium. Female bursa terminal. A pear-shaped seminal receptacle, a sclerotized tube or a muscular bulb next to the ovo-vitelloduct (except in Papia an Stradorhynchus)., Published as part of Schockaert, Ernest R., Moons, Patricia, Janssen, Toon, Tessens, Bart S., Reygel, Patrick C., Revis, Nathalie, Jouk, Philippe E. H., Willems, Wim R. & Artois, Tom J., 2019, On the genus Typhlopolycystis Karling, 1956 (Platyhelminthes, Kalyptorhynchia, Polycystididae), with data on the five known species and the description of eleven new species, pp. 81-104 in Zootaxa 4603 (1) on page 85, DOI: 10.11646/zootaxa.4603.1.4, http://zenodo.org/record/2673305, {"references":["Evdonin, L. A. (1977) Turbellaria Kalyptorhynchia in the fauna of USSR and adjacent areas. Fauna USSR, 115, 1 - 400.","Karling, T. G. (1956) Morphologisch-histologische Untersuchungen an den mannlichen Atrialorganen der Kalyptorhynchia (Turbellaria). Arkiv for Zoologi, 9, 187 - 277.","Artois, T. J. & Schockaert, E. R. (2000) Interstitial fauna of the Galapagos: Typhlopolycystidinae (Platyhelminthes Polycystididae). Tropical Zoology, 13, 141 - 158. https: // doi. org / 10.1080 / 03946975.2000.10531128"]}

Typhlopolycystis coeca Karling, 1956 (Fig. 2) Diagnosis. Yellowish species of Typhlopolycystis, 1.5 mm long with a very large proboscis (1/3 of body length) and no eyes. Prostate vesicle and accessory secretion vesicle well developed. The prostate stylet is a short and straight gutter without thickenings (20���25 ��m long) and the accessory stylet is a slightly curved tube, 26���30 ��m long, both sitting on a ring with a diameter of about 25���30 ��m over its largest cross section. Occurrence. Sweden: Kristineberg, Bredungen, silty bottom at 38 m (type locality). Other localities near Kristineberg (by Westblad and Karling). Germany: several sublittoral stations in the Bight of Kiel (by Ax) (see Karling, 1956); Koningshaven on the Island of Sylt (medium sand, eulittoral)(by Ax, 16 August 1965, Noldt, 1989). Studied material: the holotype (SMNH type nr 2701), one more whole mount of an animal from the Kristineberg area (SMNH nr 82300), and one from Sylt (SMNH nr 43585)., Published as part of Schockaert, Ernest R., Moons, Patricia, Janssen, Toon, Tessens, Bart S., Reygel, Patrick C., Revis, Nathalie, Jouk, Philippe E. H., Willems, Wim R. & Artois, Tom J., 2019, On the genus Typhlopolycystis Karling, 1956 (Platyhelminthes, Kalyptorhynchia, Polycystididae), with data on the five known species and the description of eleven new species, pp. 81-104 in Zootaxa 4603 (1) on page 85, DOI: 10.11646/zootaxa.4603.1.4, http://zenodo.org/record/2673305, {"references":["Karling, T. G. (1956) Morphologisch-histologische Untersuchungen an den mannlichen Atrialorganen der Kalyptorhynchia (Turbellaria). Arkiv for Zoologi, 9, 187 - 277.","Noldt, U. (1989) Kalyptorhynchia (Plathelminthes) from Sublittoral Coastal Areas near the Island of Sylt (North Sea). II. Eukalyptorhynchia. Microfauna Marina, 5, 295 - 329."]}

Typhlopolycystis maikoni n. sp Schockaert & Artois. (Figs 10 E–F) Diagnosis. Colourless species of Typhlopolycystis, about 1 mm long with a proboscis of 1/6–1/5 of the body length and with eyes. The prostate stylet is curved, 72 µm long with a thickened proximal “head” of about 22 µm at its concave side. The accessory stylet is attached to the prostate stylet at the opposite side. It makes a turn of 180° and then follows the curve of the prostate stylet; it ends in a point and is 77 µm long, measured from the point of attachment to the prostate stylet. Occurrence. Brasil: near the Island of Itaçucê, São Sebastião (São Paulo), shell gravel at 7 m depth. (by Schockaert, 30 October 2012) (Type Locality). Material examined. Observations on a live animal and micrographs of the live animal. One whole mount (Holotype, SMNH nr 8959) Etymology. Species name in honour of Dr. Maikon Di Domenico, who was one of the collectors of the samples near Itaçucê and who was highly involved in the logistics of the workshop on the Taxonomy and Diversity of Marine Meiofauna, Brazil. Additional data. The copulatory organ of T. maikoni n. sp. is very similar to that of T. pluvialiae n. sp.. The prostate stylet is slightly longer (72 µm) than that of T. pluvialiae n.sp (63 µm) and slightly less curved. It is also narrower. The accessory stylets are less different in length, resp. 77 µm and 74 µm. The thickened proximal curl (“head”, x in Fig. 1F) is shorter than in T. pluvialiae n.sp (22 µm and 29 µm). More obvious differences are the size of the proboscis: large (1/4 of body length) in T. pluvialiae n. sp., and less than 1/5 of body length in T. maikoni n. sp. and the fact that the Brazilian species has eyes, while the Lanzarote species does not.

Typhlopolycystis rubra Noldt and Reise, 1987 (Fig. 9) Synonyms: Typhlopolycystis spec. in Reise (1983a, 1983b,1984, 1985), Scherer (1985) Diagnosis. Species of Typhlopolycystis with an average length of 1 mm (0.5���1.6 mm) and with eyes. Many individuals are red. The proboscis is about 1/5 of the body length. The prostate stylet is 105���120 ��m, the accessory stylet 80���90 ��m both proximally attached to each other. The proximal diameter of the stylet is 38���44 ��m. These are the measurements of Noldt & Reise (1987), which we can confirm on the two specimens we have. Both stylets are bent, while the accessory stylet has a strong distal curl and ends in a sharp point. The seminal receptacle has the form of a chilli pepper. Occurrence. Germany: Isle of Sylt, Koeningshafen, sandy lugworm flat in the lower tidal zone. This species lives in the burrows of the lugworm Arenicola marina. Material examined. Two whole mounts (syntypes) (ZMUG 8837���ex P 1999���2000). The holotype (a sectioned specimen) was not available., Published as part of Schockaert, Ernest R., Moons, Patricia, Janssen, Toon, Tessens, Bart S., Reygel, Patrick C., Revis, Nathalie, Jouk, Philippe E. H., Willems, Wim R. & Artois, Tom J., 2019, On the genus Typhlopolycystis Karling, 1956 (Platyhelminthes, Kalyptorhynchia, Polycystididae), with data on the five known species and the description of eleven new species, pp. 81-104 in Zootaxa 4603 (1) on page 92, DOI: 10.11646/zootaxa.4603.1.4, http://zenodo.org/record/2673305, {"references":["Scherer, B. (1985) Annual dynamics of a meiofauna community from the \" sulfide layer \" of a North Sea sand flat. Microfauna Marina, 2, 117 - 161."]}

Typhlopolycystis pluvialiae n. sp Artois, Jansens and Schockaert. (Figs 10 A���D) Diagnosis. Colourless species of Typhlopolycystis, about 1 mm long with a proboscis of 1/4 of the body length and without eyes. The prostate stylet is curved, 63 ��m long with a thickened proximal ���head��� of about 29 ��m at its concave side (x in Fig. 10D). The accessory stylet is attached to the prostate stylet at the opposite side. It makes a turn of 180�� and then follows the curve of the prostate stylet; it ends in a point and is 74 ��m long, measured from the place where it is attached to the prostate stylet. Occurrence. Spain: Isle of Lanzarote (Canary Islands), Mala, large sand patch among rocks, medium-fine, calcareous sand, not well-oxygenated (reduced just below surface), 20 m deep (29��5' 0.53"N, 13��26' 59.10"W) (by Artois & Jansens, 0 8 October 2011) (Type Locality). Material examined. Observations and micrographs of a living animal. One whole mount (Holotype, SMNH nr 8916). Etymology. Pluvialia was the Roman name of Lanzarote., Published as part of Schockaert, Ernest R., Moons, Patricia, Janssen, Toon, Tessens, Bart S., Reygel, Patrick C., Revis, Nathalie, Jouk, Philippe E. H., Willems, Wim R. & Artois, Tom J., 2019, On the genus Typhlopolycystis Karling, 1956 (Platyhelminthes, Kalyptorhynchia, Polycystididae), with data on the five known species and the description of eleven new species, pp. 81-104 in Zootaxa 4603 (1) on pages 92-93, DOI: 10.11646/zootaxa.4603.1.4, http://zenodo.org/record/2673305

Typhlopolycystis coomansi Schockaert & Karling, 1975 (Fig. 7) Diagnosis: Yellowish-brown species of Typhlopolycystis with a very large proboscis (1/3 of body length) and with eyes. The hard parts of the copulatory organ consist of a small main stylet of 26 ��m (n=4, 22 ��m in the holotype) with rounded ���lips��� and no thickenings, and a strong straight accessory stylet of 68 mm (n=4, 60 ��m in the holotype) that ends in a sharp curled hook, both sitting on a ring of about 20 by 40 mm. Occurrence. France: Plateau des Ch��vres in the Gulf of Marseille, Amphioxus -sand, at 8���10 m depth (by Brunet, 3 February 1966 ��� type locality); Banyuls-sur-Mer, Labo Arago, L���Herbier, at the end of the longest pipeline, sand with silt and rocks, 10 m deep (by Revis & Jouk, 8 July 2008). Norway: S. of Bergen, Korsfjord, Liholmen, fine sand at 7 m (by Karling, 29 July 1968). Portugal: Faro, opposite the Island of Barretta (Algarve), coarse sand with shell debris at 26 m depth (by Tessens, 23 May 2013). Material examined. The holotype (whole mount, SMNH type nr 2702). Observations on the living animals from Banuyls and Faro and micrographs of the living animals. Two whole mounts from Banyuls (HU nrs IX.4.31���32) and one from Faro (HU nr IX.4.33). The whole mount of the specimen from Liholmen (SMNH nr 43589). Additional data. In the original description, data were included from a living specimen from the isle of Tekslo (Norway) because the authors wrongly assumed that the curved accessory stylet was an artefact. Of this specimen, no whole mount exists and with the drawing given (figure 41 in Schockaert & Karling (1975)) an unambiguous identification cannot be made; but this animal has a straight accessory stylet and is therefore most probably not T. coomansi. They also present a drawing (figure 34) and a micrograph (figure 37) of the copulatory organ of an individual from Liholmen (Norway) that they consider a representative of T. mediterranea. However, when studying the copulatory organ of the individual from Faro, especially when comparing the situation in the slightly squeezed animal (Fig. 7B) with the situation in the whole mount (Fig. 7F) we realised that the copulatory organ in the micrograph is very similar to that of the Norwegian specimen (Fig. 7G). Re-studying this specimen more carefully, we observe that it appears to have an accessory stylet with a sharp curled ending, directed upwards, however, and thus difficult to see when one is not adverted., Published as part of Schockaert, Ernest R., Moons, Patricia, Janssen, Toon, Tessens, Bart S., Reygel, Patrick C., Revis, Nathalie, Jouk, Philippe E. H., Willems, Wim R. & Artois, Tom J., 2019, On the genus Typhlopolycystis Karling, 1956 (Platyhelminthes, Kalyptorhynchia, Polycystididae), with data on the five known species and the description of eleven new species, pp. 81-104 in Zootaxa 4603 (1) on pages 89-91, DOI: 10.11646/zootaxa.4603.1.4, http://zenodo.org/record/2673305, {"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. https: // doi. org / 10.1111 / j. 1463 - 6409.1975. tb 00725. x"]}

Typhlopolycystis norenburgi n. sp Artois and Schockaert. (Fig. 6) Diagnosis. Species of Typhlopolycystis around 2 mm, without eyes and with a small proboscis, 1/8 of the body length. The prostate stylet is 25 µm long, 14 µm at its base. It narrows to 5 µm and broadens to about 11 µm at the end. The accessory stylet is 49 µm long with a funnel-like proximal end; the opening is 11 µm wide and the stylet narrows quickly to 4 µm and ends at less than 1 µm. The distal half of the accessory stylet makes a circular turn of 180°. The proximal ring is about 18 µm in diameter. The seminal receptacle consists of two successive vesicles. Occurrence. Panama: Isla Pedro Gonzalez (Las Perlas), coarse sand from near to a mangrove, 2.5 m deep at medium level tide (8°23'14.57"N, 79° 5'1.73”W) (by Artois, December 12, 2011) (Type Locality). Material examined. Observations and micrographs of the living animal. One whole mount designated the holotype (USNM nr 1523610). Etymology. Species name in honour of Dr. J. Norenburg (Smithsonian Institution), who organised the sampling campaign in Panama in 2011.

Typhlopolycystis mediterranea Brunet, 1965. (Fig. 8) Diagnosis. Orange light-brownish species of Typhlopolycystis, about 2 mm with a large proboscis of 1/3 of body length and with eyes. The hard parts of the copulatory organ are robust. The prostate stylet is highly curved with a thick wall at the concave side. It is 25���43 ��m long (n=6). The accessory stylet is 60���83 ��m long (n=6). Both stylets are attached to a ring of about 45���58 ��m (n=6). Occurrence. France: Gulf of Marseille in Amphioxus sand (see Brunet, 1965) (Type locality); Cerb��re, Terrimbou, Les Alo��s, in front of the little jetty, clean sand, 8 m deep, (by Revis & Jouk, 29 July 2007); Sweden: Isle of Bonden (West Coast), shell gravel, 20���30m (by Karling, 0 7 August 1961 and by Schockaert, 11 July 1974). Material studied. The holotype as indicated by Brunet (1965) (SMNH nr 96866, sectioned specimen) and three whole mounts from the type locality (syntypes SMNH nrs 96868, 43586 and SMNH typ 2703, the latter indicated as holotype by Karling in Schockaert & Karling (1975, p. 140). Whole mounts of the two specimens from the Kristineberg area (SMNH nrs 43588 and 96658) and two whole mounts from Cerb��re (HU nrs IX.4.36���37). Additional data. Schockaert & Karling (1975) consider T. limicola Schilke, 1970 as a synonym of T. mediterranea. The drawing of Schilke in his figure 5B makes this possible. But with our present knowledge, it has become clear that differences are often very subtle. Moreover, the proboscis of T. limicola (figure 5 in Schilke, 1970) seems to be much smaller than in T. mediterranea (1/5 against 1/3 of body length). As long as there is no material available of ��� T. limicola ��� from the type locality (N-E beach on Sylt), we prefer to consider this species as a species inquirenda., Published as part of Schockaert, Ernest R., Moons, Patricia, Janssen, Toon, Tessens, Bart S., Reygel, Patrick C., Revis, Nathalie, Jouk, Philippe E. H., Willems, Wim R. & Artois, Tom J., 2019, On the genus Typhlopolycystis Karling, 1956 (Platyhelminthes, Kalyptorhynchia, Polycystididae), with data on the five known species and the description of eleven new species, pp. 81-104 in Zootaxa 4603 (1) on pages 91-92, DOI: 10.11646/zootaxa.4603.1.4, http://zenodo.org/record/2673305, {"references":["Brunet, M. (1965) Turbellaries calyptorhynques de substrats meubles de la region de Marseille. Recueil des travaux de la station marine d'Endoume, 39, 127 - 220.","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. https: // doi. org / 10.1111 / j. 1463 - 6409.1975. tb 00725. x","Schilke, K. (1970) Kalyptorhynchia (Turbellaria) aus dem Eulitoral der Deutschen Nordseekuste. Helgolander wissenschaftliche Meeresuntersuchungen, 21, 143 - 265. https: // doi. org / 10.1007 / bf 01630522"]}

Typhlopolycystis leasiae n. sp. Artois and Schockaert. (Fig. 11) Diagnosis. Species of Typhlopolycystis, 0.7 mm long with two small eyes close to each other. The proboscis is huge, at least 1/3 of the body length and the pharynx is small. The prostate stylet and the accessory stylet are proximally attached to each other. The prostate stylet is slightly bent, 62 µm long and 8 µm broad proximally and with a blunt rounded end of about 5 µm broad. The accessory stylet is 70 µm long with a proximal diameter of 8 µm. From its base, it first narrows, then broadens again to 7 µm and then tapers to a fine end. The seminal receptacle consists of two vesicles. Occurrence. Panama: Achotines Bay, right side of pipeline, next to rocks, fine sand (7°24'53.48'' N, 80°10'25.1364''W) (by Artois, 22 February 2016) (Type Locality). Material examined. Observations on, and micrographs of the living animal. One whole mount, the holotype (USNM nr 1523611). Etymology. Species name in honour of Dr. F. Leasi (Smithsonian Institution), who organised the sampling campaign in Panama in 2016.

Genus Typhlopolycystis Karling, 1956 Type species. Typhlopolycystis coeca Karling, 1956 by original monotypy. Diagnosis. Typhlopolycystidinae with a gutter-like prostate stylet and a tubiform accessory stylet, proximally attached to each other directly or by a ring, or not at all; accessory secretion reservoir (mostly) present, evacuated by the accessory stylet. With a muscular ���seminal receptacle��� at the entrance of the oviduct., Published as part of Schockaert, Ernest R., Moons, Patricia, Janssen, Toon, Tessens, Bart S., Reygel, Patrick C., Revis, Nathalie, Jouk, Philippe E. H., Willems, Wim R. & Artois, Tom J., 2019, On the genus Typhlopolycystis Karling, 1956 (Platyhelminthes, Kalyptorhynchia, Polycystididae), with data on the five known species and the description of eleven new species, pp. 81-104 in Zootaxa 4603 (1) on page 85, DOI: 10.11646/zootaxa.4603.1.4, http://zenodo.org/record/2673305, {"references":["Karling, T. G. (1956) Morphologisch-histologische Untersuchungen an den mannlichen Atrialorganen der Kalyptorhynchia (Turbellaria). Arkiv for Zoologi, 9, 187 - 277."]}

Paraustrorhynchus smeetsae Artois, Reygel, Tessens & Van Steenkiste n. sp. Paraustrorhynchus n. sp. in Tessens et al. 2014 (Fig. 6) Locality. Goa (India), AIT Beach (15��34���2.8���N, 73��44���28.5���E), protected bay with coarse sand with shell gravel, specimens collected by B. Tessens and N. Van Steenkiste, 3 rd and 12 th December 2008. Material examined. Several animals studied alive, five whole mounts (three suitable for observation of hard structures), one whole mount designated holotype (FMNH http://id.luomus.fi/KV.607), the others paratype (HU 591���594) two additional serially-sectioned (sagitally) specimens (HU 595���596). Etymology. Named after Prof. Karen Smeets (UHasselt), in appreciation of her dedication towards the UHasselt research group. Diagnosis. Species of Paraustrorhynchus with a dorsal dark-blue pigment pattern consisting of a transversal band dorsally from the pharynx, separated from a mid-dorsal band in the second body half. Prostate stylet type II double walled, �� 47 ��m long, funnel-shaped, curved, with two fin-like structures just proximal from the curve. Outer stylet with proximal longitudinal slit; inner stylet lacking in the proximal 1/3 of the stylet. Prostate stylet type III �� 26 ��m, consisting of a common proximal plate �� 38 ��m broad, from which two arms depart. Both arms with broad serrated distal ends, �� 24 ��m and 16 ��m wide respectively, are largely overlapping. Description. The animals are opaque, with scattered light-brown pigment and a prominent blue pigment pattern (Fig. 6 A, B) consisting of a transversal band dorsally from the pharynx separated from a longitudinal band in the caudal body half. The pigmentation consists of small granules under the body wall. Its relation to specific cells is not clear, but the pattern is similar in the observed animals. Depending on the degree of contraction and squeezing, internal structures such as the copulatory bulb may disrupt the pigment pattern. The animals have two eyes and are 300���700 ��m long (��� = 530 ��m; n = 5; measured on whole mounts). The internal organisation, including that of the male and female atrial system, corresponds completely to that of P. isoldeae (see above). The stylet type II (Fig. 6 D, E) is 45���49 ��m long (x���= 47 ��m; n = 3). It is a doublewalled, curved tube. Near the distal, pointed end the stylet is twisted over a short distance. The inner stylet can be followed over the whole length of the outer stylet except in the distal twist and in the proximal 1/3 of the stylet. At one side, the proximal 1/3 of the outer stylet shows a longitudinal slit, which broadens at the level of the proximal end of the inner stylet, leaving the inner stylet apparently uncovered at this side. At about its midpoint, the outer stylet is provided with two small, fin-like structures. In one whole mount, one of the fin-like structures is missing; probably it is not visible due to compression and orientation of the stylet. The prostate stylet type III (Fig. 6 G, F) consists of two arms proximally connected to a single folded broad plate (36���41 ��m wide; x���= 38 ��m; n = 3). The ventral arm widens to a broad plate (20���29 ��m wide; x���= 24 ��m; n = 3), and has �� 3/4 of the its distal rim serrated. The dorsal arm ends in a less broad plate (15���17 ��m wide; x���= 16 ��m; n = 3), which has a completely serrated distal rim. Both arms are almost equal in length and determine the length of the stylet type III (24���30 ��m; x���= 26 ��m; n = 3). Measurements of the length and especially the width in the middle of the stylet depends on the inclination of the proximal plate and the position of both arms due to the compression of the preserved specimens., Published as part of Lin, Yitao, Reygel, Patrick, Feng, Weitao, Chen, Jiajia, Tessens, Bart, Van Steenkiste, Niels W. L., Schockaert, Ernest R., Artois, Tom J. & Wang, Antai, 2019, Four new species of the genus Paraustrorhynchus (Rhabdocoela: Kalyptorhynchia: Polycystididae), pp. 357-373 in Zootaxa 4550 (3) on pages 366-367, DOI: 10.11646/zootaxa.4550.3.4, http://zenodo.org/record/2625481, {"references":["Tessens, B., Janssen, T. & Artois, T. (2014) Molecular phylogeny of Kalyptorhynchia (Rhabdocoela, Platyhelminthes) inferred from ribosomal sequence data. Zoologica Scripta, 43 (5), 519 - 530. https: // doi. org / 10.1111 / zsc. 12066"]}

Lin, Yitao, Reygel, Patrick, Feng, Weitao, Chen, Jiajia, Tessens, Bart, Van Steenkiste, Niels W. L., Schockaert, Ernest R., Artois, Tom J., Wang, Antai (2019): Four new species of the genus Paraustrorhynchus (Rhabdocoela: Kalyptorhynchia: Polycystididae). Zootaxa 4550 (3): 357-373, DOI: https://doi.org/10.11646/zootaxa.4550.3.4

Paraustrorhynchus isoldeae Artois, Reygel & Schockaert n. sp. (Fig. 5) Locality. Noum��a (New Caledonia): Baie des Citrons (22��17'43"S, 166��26'8"E), on algae and on seagrass in the lagoon, 8 th August 2003 (Type locality); Nouville (New Caledonia), on algae (Pavonia sp.) collected on the beach west of the Centre Hospitalier Sp��cialis�� (CHS) Albert-Bousquet (22��15��� 59"S, 166��23���41"E), 10th August 2003. All collections by E. Schockaert. Material examined. Several animals studied alive, one of which with an egg. Two whole mounts, one designated holotype (FMNH, http://id.luomus.fi/KV.606), the other paratype (HU 590). Etymology. Named after Isolde Artois, daughter of TA. Diagnosis. Species of Paraustrorhynchus with mid-dorsal dark-blue Y-shaped pigment pattern. The pigmentation consists of small granules under the body wall, its relation to specific cells is not clear but the pattern is similar in all observed animals. Prostate stylet type II �� 80 ��m long, L-shaped, with both halves more or less of equal length, ending in a sharp point. Proximal half funnel-shaped, showing a longitudinal slit. Inner stylet lacking in the most proximal half of the stylet. Prostate stylet type III consisting of a proximal, folded plate from which two arms depart. One arm rather straigth, broadening towards a 35-��m-broad distal rim, provided with teeth. The other arm more curved, ending in a blunt point that is asymetrically serrated. Prostate stylet type III in total ��41 ��m long, ��45 ��m wide proximally, ��10 ��m wide in the middle and ��35 ��m distally. Description. The animals are 1.3 to 1.6 mm long (measured on whole mounts). The length based on a micrograph of a live specimen is 1.2 mm. The animals are opaque, with scattered light-brown pigment and a prominent dark blue Y-shaped dorsal pigment pattern (Fig. 5A). Anteriorly, the dark blue pigmentation, organised in irregular patches, runs from side to side behind the eyes as a narrow band. Mid-dorsally, the dark blue pigmentation runs from behind the eyes to the posterior end of the animal. The pigmentation consists of small granules just beneath the body wall. Depending on the degree of contraction of the animal and squeezing, internal structures such as an egg or the copulatory bulb may disrupt the pigment pattern. The pigmentation disappears in fixed specimens. The proboscis measures about 1/8 of the body length in live animals. The pharynx is situated in the first body half. The gonads are paired. The testes lie almost behind the pharynx. Vitellaria are situated dorsally and extend at both sides from the pharynx to the caudal body end. Well-defined, yellowish-brownish ovaries lie at the caudal body end. The internal organisation, including that of the male and female atrial system, corresponds to that of P. pacificus (see Karling & Schockaert 1977 for details). The prostate stylet type II (Fig. 5C,E) is 74���85 ��m long. It is L-shaped, with a funnel-shaped proximal part and a sinusoid distal part, which tapers towards a pointed end. Both parts are more or less of equal length. The inner stylet is clearly visible over most of the length of the stylet, but is lacking in the proximal half of the funnel-shaped part. This part shows a broad longitudinal slit. The prostate stylet type III (Fig. 5B,D) consists of a proximal folded plate, from which two arms depart. One arm departs from one proximal corner of the common plate and runs more or less straight, widening to a 35-��m-broad and serrated distal rim (only one specimen measured, the other has a partialy-folded stylet, not suitable for exact measurement). The second arm departs from the opposite proximal corner of the common plate and is somewhat curved, with a blunt end that is asymetrically serrated. In total the prostate stylet type III is 39���43 ��m long and 44���45 ��m wide proximally, 9���11 ��m wide at its midpoint., Published as part of Lin, Yitao, Reygel, Patrick, Feng, Weitao, Chen, Jiajia, Tessens, Bart, Van Steenkiste, Niels W. L., Schockaert, Ernest R., Artois, Tom J. & Wang, Antai, 2019, Four new species of the genus Paraustrorhynchus (Rhabdocoela: Kalyptorhynchia: Polycystididae), pp. 357-373 in Zootaxa 4550 (3) on pages 362-364, DOI: 10.11646/zootaxa.4550.3.4, http://zenodo.org/record/2625481, {"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. https: // doi. org / 10.1111 / j. 1463 - 6409.1977. tb 00755. x"]}

Myobulla berti Roosen, Diez, Reygel & Artois sp. n. (Fig. 6, 7 C–D) Material and distribution in Panama. Fifteen specimens studied alive and whole mounted and four seriallysectioned specimens (three sagitally-sectioned ones and one horizontally sectioned) from Bahía Can Can, near to Portobelo, Panama (type locality) (9°32’23”N; 79°40’31”W), subtidally in a lagoon, fine-grained sand with some organic matter taken in between sea grass, 0.2 m deep at low tide, fine-grained sand taken intertidally in channels between the mangroves and medium coarse sand, 0.8 m deep, taken at the front side of the reef (March 3, 2016), one whole mounted specimen designated holotype (deposited USMNH 1480556), all the rest reference material deposited in the USMNH too (without reference number yet). Etymology. Species dedicated to Prof. Dr. Wim Bert (Ghent University, Belgium), an excellent taxonomist of soil nematodes and a dear friend of TA. Diagnosis. Species of Myobulla with a prostate stylet type III 73 µm long, with a 90° curve in the middle and a distal flap. Proximal part of the stylet slightly smaller than the distal part. Description. Animals about 1 mm long (measured on live animals), with two eyes (Fig. 6 A–B: e) and colourless, except for some long, pink glands along both sides of the body. Habitus and internal morphology similar to that of other species of Myobulla, hence, with unpaired gonads and a typical bursal stalk provided with an asymmetrical muscular bulb with a ring of four hard teeth. For a detailed description we refer to Artois & Schockaert (2000). Prostate stylet type III (Fig. 6 A–C, E: ps3, 6F, 7C–D) 67–79 µm long (x̄ = 73 µm; n = 16). Proximal part gutter shaped, twisted around its axis and with an enlarged proximal end. Distal part tubiform, more or less perpendicular to the proximal part (90%) in more or less strongly-squeezed animals (Fig. 7C) whereas the entire stylet is more straight in less-squeezed ones (Fig. 7D). With a flap at about the middle of the distal tubular half. Proximal part of the stylet slightly smaller than the distal part (90%). The seminal duct enters the male atrium at the level where the stylet becomes tubiform, as in the other species of Myobulla. A bundle of basophilic glands opens into the male atrium (accessory glands type II). Female system as in other species of Myobulla. Ovary kidney shaped, with the oocytes diminishing in diameter from the most distal to the most proximal. Bursa globular, with the muscular seminal receptacle with a ring of four teeth characteristic of the genus. Discussion. Based in the general morphology and the detailed structure of the prostate stylet, the new species can easily be placed within Myobulla. The most conspicuous feature of the genus, the muscular seminal receptacle with a ring of four teeth (see Artois & Schockaert 2000; 2003), could easily be seen on all live specimens studied. In all species, the prostate stylet is proximally gutter shaped, becoming tubiform more distally. Four of the five species (including the two new species described in this paper) have a hook-shaped stylet; only in M. myobulla Artois & Schockaert (2000) is it straight. The stylets of the other four species differ mostly in the relative length of the proximal part compared to that of the distal part, and in the detailed morphology. The stylet of M. dunata Artois & Schockaert, 2000 is sturdier in general, and its distal part is shorter than the proximal part. Myobulla swedmarki (Karling, 1978) Artois & Schockaert, 2000 has a stylet that has a much longer proximal part (Fig. 7A), and the stylet is more delicate than that of M. dunata, M. armenterosi sp. n., and M. berti sp. n.. The distal twisted tip of the stylet in M. armenterosi sp. n. is unique within the genus Myobulla. The flap-like part at the level of the curve in the stylet is unique for M. berti sp. n.. As was shown in the specimens of M. armenterosi sp. n. and M. berti sp. n., the degree of squeezing can give the stylet a different appearance (see Fig. 7), as was already discussed by Karling (1978) for M. swedmarki, but the distal and proximal part can always be easily recognised. Moreover, there seems to be some intraspecific variation in M. swedmarki, for which we refer to Karling (1978).

Alcha evelinae Marcus, 1949 (Fig. 3 C���D) Material and distribution in Cuba. Observations on live animals, whole mounted afterward. One whole mount from Siboney (April 4, 2017), on Gracilaria sp., 0.3 m depth, salinity 34 ���. Five whole mounts from Bueycab��n (February 6 & 21, 2018), on leaves of Thalassia testudinum and Syringodium filiformis, 0.5 m depth, salinity 33 ���. All reference material in HU (VIII.3.05��� VIII.3.10). Remarks. The habitus and the internal organization of the studied specimen do not deviate from those mentioned in the original description by Marcus (1949) and by Karling & Schockaert (1977), including the typical blue pigmentation (Fig. 3D). The prostate stylet type III (Fig. 3D) of the Cuban specimens is 31���39 ��m long (x�� = 35 ��m; n = 6), which is within the range mentioned in literature: 33���53 ��m (Marcus 1949; Karling & Schockaert 1977; Jouk & De Vocht 1989; Artois & Tessens 2008)., Published as part of Diez, Yander L., Hern��ndez, Claudia Sanjuan, Reygel, Patrick, Roosen, Paulien & Artois, Tom, 2018, First record of Polycystididae (Platyhelminthes, Kalyptorhynchia) from Cuba, with the description of a new genus and five new species, and remarks and the description of one new species from Panama, pp. 107-125 in Zootaxa 4514 (1) on page 115, DOI: 10.11646/zootaxa.4514.1.9, http://zenodo.org/record/2605858, {"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. https: // doi. org / 10.1111 / j. 1463 - 6409.1977. tb 00755. x","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. https: // doi. org / 10.1080 / 03946975.1989.10539435","Artois, T. J. & Tessens, B. S. (2008) Polycystididae (Rhabditophora: Rhabdocoela: Kalyptorhynchia) from the Indian Ocean, with the description of twelve species. Zootaxa, 1849, 1 - 27."]}

Myobulla armenterosi Diez, Sanjuan, Reygel & Artois sp. n. (Fig. 5, 7B) Material and distribution in Cuba. Observations on live animals, whole mounted afterward. Six whole mounts from Bueycab��n (type locality) (March 3, 2016), one of which is designated holotype (FMNH http://id.luomus.fi/ KV.605), fine-grained sand with organic matter, 0.5 m depth, salinity 32���33 ���. The other five specimens reference material (HU VIII.3.33��� VIII.3.37). One whole mount from Aguadores (February 14, 2017), on Cladophoropsis macromeres, 0.3 m depth, salinity 35 ��� (HU VIII.3.38). Etymology. Species dedicated to Prof. Dr. Maickel Armenteros (Marine Research Centre, Havana University, Cuba). Diagnosis. Species of Myobulla with a prostate stylet type III 68 ��m long, with a 90�� curve at its midpoint and its distal tip more or less hook shaped. Description. Animals 0.6���1 mm long (x�� = 0.9 mm; n = 7) (measured on the whole mounts), with two eyes (Fig. 5A: e) and colourless, except for some long, pink glands along both sides of the body. Habitus and internal morphology similar to that of other species of Myobulla, hence, with unpaired gonads and a typical bursal stalk provided with an asymmetrical muscular bulb with a ring of four hard teeth. For a detailed description we refer to Artois & Schockaert (2000). Proboscis (Fig. 5A: pr) 91���131 ��m long (x�� = 110 ��m; n = 7). Pharynx (Fig. 5A: ph) 113���186 ��m in diameter (x�� = 162 ��m; n = 7), located at 40%. Prostate stylet type III (Fig. 5 A���B: ps3, 5D���E) 58���86 ��m long (x�� = 68 ��m; n = 7). Proximal part gutter shaped, with a thickened proximal end, 11���18 ��m wide (x�� = 17 ��m; n = 7). Distal part tubiform, more or less perpendicular to the proximal part in more or less strongly-squeezed animals (Fig. 5 D���E) whereas the entire stylet is more straight in less-squeezed ones (Fig. 7B). Distal tip of the stylet somewhat hook-shaped. Proximal part represents 45���59% of the length of the stylet (x�� = 53%; n = 7). The seminal duct enters the male atrium at the level where the stylet becomes tubiform, as in the other species of Myobulla. Female system as in other species of Myobulla. Ovary kidney shaped, with the oocytes in a row, diminishing in diameter from the most distal to the most proximal. Bursa globular, with the muscular seminal receptacle with a ring of four teeth characteristic of the genus., Published as part of Diez, Yander L., Hern��ndez, Claudia Sanjuan, Reygel, Patrick, Roosen, Paulien & Artois, Tom, 2018, First record of Polycystididae (Platyhelminthes, Kalyptorhynchia) from Cuba, with the description of a new genus and five new species, and remarks and the description of one new species from Panama, pp. 107-125 in Zootaxa 4514 (1) on page 120, DOI: 10.11646/zootaxa.4514.1.9, http://zenodo.org/record/2605858, {"references":["Artois, T. J. & Schockaert, E. R. (2000) Interstitial fauna of the Galapagos: Typhlopolycystidinae (Platyhelminthes Polycystididae). Tropical Zoology, 13, 141 - 158. https: // doi. org / 10.1080 / 03946975.2000.10531128"]}

Polycydora intermedia Diez, Sanjuan, Reygel & Artois sp. n. (Fig. 4) Material and distribution in Cuba. Observations on live animals. Five whole mounts, one of which is designated holotype (FMNH http://id.luomus.fi/ KV.604), and ten serially-sectioned specimens collected in Bah��a de Gibara (type locality) (March 26, 2017), sublittoral, in coarse sand, 0.6 m depth, salinity 35 ���. Three whole mounts from Siboney (May 15, 2016 & June 5, 2017), intertidal, upper 10 cm of fine sand with organic matter, salinity 35 ���. One whole mount from Bueycab��n (February 6, 2018), intertidal, upper 10 cm of fine sand, salinity 33 ���. All reference material in HU (VIII.3.15��� VIII.3.32). Etymology. The epithet refers to the fact that the new species is morphologically intermediate between Polycystis and Paulodora. Diagnosis. Species of Polycydora gen. n. with a 75-��m-long prostate stylet type II. The outer stylet is proximally funnel shaped, ��18 ��m wide, then is constricted to a tube 4 ��m wide. At one-third of its length it shows a 180�� turn. Stylet with an asymmetrical distal opening. Description. Living animals 1.5 mm long. Length measured on whole mounts 0.9���1.5 mm (x�� = 1.2 mm; n = 4). Translucent, with a pair of eyes. Syncytial epidermis 7 ��m thick and ciliated, cilia 6���7 ��m long. Two types of vacuoles present in the epidermis: empty ones (support structures) and others filled with small granules. Rhabdites as large as the height of the epidermis, only present in the posterior two-third of the body. Proboscis of the typical polycystidid type (Fig. 4 A���B: pr, Fig. 4C; for a detailed description see Meixner, 1925), 1/5 of the body length, with six pairs of fixator muscles (Fig. 4C: pfix). With four pairs of proboscis retractors (Fig. 4C: pret). Cone retractors well-developed (Fig. 4C: cret). As in most Polycystididae with a pair of ventral integument retractors (Fig. 4C: ir). Proboscis sheath surrounded by an internal circular and an outer longitudinal muscle layer. Without nuclei at the junction between sheath and cone epithelium. Thin dilator muscles are present in the distal half of the proboscis sheath (Fig. 4C: dil). Proboscis opening surrounded by a sphincter (Fig. 4C: sph). Proboscis glands can be observed just caudally from the proboscis: one central large gland producing an eosinophilic fine-grained secretion (Fig. 4C: peg), and surrounding it, coarse-grained basophilic glands (Fig. 4C: pbg). Pharynx located at about 35% (Fig. 4 A���B: ph, Fig. 4D), measuring 153���174 ��m in diameter (x�� = 162 ��m; n = 4). Prepharyngeal cavity (Fig. 4D: ppc) lined with a nucleated epithelium surrounded by an internal layer of circular muscles and an external layer of longitudinal muscles, opening to the outside through the mouth (Fig. 4D: m). Pharynx bulb with the normal polycystidid construction, showing the four teeth surrounding the proximal pharynx opening, typical of the family (Fig. 4D: th). Three types of glands open in the distal part of the pharyngeal lumen, which are, from distal to proximal: eosinophilic glands (stained light pink) (Fig. 4D: phg1), basophilic glands with a coarse-grained secretion (stained dark blue-black) (Fig. 4D: phg2), and eosinophilic glands with a fine-grained secretion (stained brownish) (Fig. 4D: phg3). At its distal side the pharynx has a muscular sphincter (Fig. 4D: sph), just distal from the opening of the glands. The musculature of the pharynx consists of an external layer of circular muscles (Fig. 4D: cm), just inside of the septum and a longitudinal muscle (Fig. 4D: lm) layer just outside of it, which is continuous with the longitudinal muscle layer of the prepharyngeal cavity. The pharynx lumen is surrounded by a circular muscle layer and a longitudinal one. Radial muscles run between the internal and the external walls (Fig. 4D: rm). Genital organs situated in the middle section of the body. Testes (Fig. 4B: t) situated caudally to the pharynx. Seminal vesicles (Fig. 4B & 4E: sv) located between the testes and delineated by a thin nucleated epithelium. Both seminal vesicles fuse to form a thin ejaculatory duct (Fig. 4E: ed), covered by circular muscles. The ejaculatory duct runs aside the prostate vesicle, entering the male genital atrium next to the proximal funnel of the prostate stylet type II. Prostate vesicle type II elongated (Fig. 4B & 4E: pv2), 63���77 ��m long (x�� = 69 ��m; n = 4) and 18���30 ��m wide (x�� = 23 ��m; n = 4), filled with an eosinophilic secretion. Prostate vesicle surrounded by two muscular layers: external oblique fibres, and internal longitudinal fibres. Prostate vesicle connected proximally to brownish accessory glands type I (Fig. 4B & 4E: ag1). Prostate stylet type II double walled and sickle shaped (Fig. 4 A���B & 4E: ps2, Fig. 4F), 60���87 ��m long (x�� = 75 ��m; n = 8), with a proximal funnel, 16���21 ��m wide (x�� = 18 ��m; n = 8). Distally from the funnel, the stylet is 4���5 ��m wide (x�� = 4 ��m; n = 8), showing a 180�� twist. Male bursa (Fig. 4B & 4E: mb) well developed, surrounded by a thick muscular coat, filled with sperm and separated from its muscular stalk by a sphincter (Fig. 4E: sph). Epithelium with nuclei surrounds the bursal stalk and the male atrium. Bursal stalk entering the common genital atrium (Fig. 4E: cga) dorsally, at the same place as does the male genital atrium. The internal vesicle of the male bursa is surrounded by a tick sheath of syncytial epithelium (Fig. 4E: se) Ovaries kidney shaped (Fig. 4B & 4E: ov) and located in the posterior third of the body. Oocytes organised in a row, diminishing in size from the most distal one to the most proximal one. Paired vitellaria extend at both sides from the middle to the end of the body (Fig. 4 A���B & 4E: vi). Oviducts very short, each receiving a vitelloduct. Both oviducts unite to form a short common female duct type I that enters the common genital atrium caudally. Oviducts and female duct are lined by a nucleated epithelium. Muscles are not well defined around the oviducts and the female duct, however, there seems to be an internal layer of circular muscles and an external layer of longitudinal ones. Large female bursa 50 ��m long (measured in one sectioned specimen), contains a central space with sperm and nuclei. It connects to the female duct by a bursal stalk at the junction of the two oviducts. Bursal stalk lined by a nucleated epithelium. Muscle layers are not observable around the female bursa and the stalk. A uterus (Fig. 4E: ut) with nucleated epithelium connects at the anterior side of the common genital atrium. Two rings of glands can be observed at the distal end of the uterus: one coarse-granulated basophilic gland (Fig. 4E: ubg), and one fine-granulated eosinophilic gland (Fig. 4E: ueg) separated from the nucleated epithelium by a dense structure, which could be a thick sphincter (Fig. 4E: x). Common genital atrium opens externally by a common gonopore (Fig. 4E: cg). Discussion. The new species shows all diagnostic features of Polycystididae, the most typical of which are the presence of four teeth around the proximal pharynx opening and of three pairs of proboscis fixators (Karling 1964). It lacks the typical features of the subtaxa Gyratricinae [unpaired ovaries; terminal (male) gonopore; unpaired seminal vesicle], Scanorhynchinae (position of external muscles of proboscis sheath inverted), Phonorhynchoidinae (proboscis sheath without circular muscles, subterminal gonopore combined with a very long genital atrium), Psammopolycystidinae (syncytial epidermis) and Typhlopolycystidinae (unpaired ovarium, enlarged proximal dilators of the proboscis sheath, typical seminal receptacle on the bursal stalk) (for details see Tessens et al. 2014 and references therein). Therefore, it can be included in Polycystidinae, a morphologically heterogeneous group, comprising most of the polycystidid taxa for which at this moment no clear apomorphies can be given (see Tessens et al. 2014). The male atrial organs of P. intermedia gen. n. sp. n. include a double-walled prostate stylet type II, found in several representatives of Polycystidinae (Antiboreorhynchus Karling, 1952, Austrorhynchus Karling, 1952, Cincturorhynchus Evdonin, 1970, Paraustrorhynchus, Phonorhynchus Graff, 1905, Porrocystis Reisinger, 1926, Progyrator Sekera, 1901, and Pygmorhynchus Artois & Schockaert, 1999 (see Artois & Schockaert 2003). In these genera the prostate stylet is connected to a prostate vesicle type II. However, all these genera (except Progyrator and Pygmorhynchus) include an accessory stylet in the male atrium, a structure lacking in P. intermedia gen. n. sp. n. The prostate vesicle type II of P. intermedia gen. n. sp. n. contains only an eosinophilic secretion, while in the other genera of the subfamily with this kind of prostate vesicle the secretion is basophilic (Artois & Schockaert 2003). Only in species of Gyratrix, Gyratricella Karling, 1955, and Papia Karling, 1956 does the prostate vesicle type II contain an eosinophilic secretion (Artois & Schockaert 2003), but these taxa differ from P. intermedia gen. n. sp. n. by many other diagnostic characters, as they belong to different subfamilies (Tessens et al. 2014). Polycydora intermedia gen. n. sp. n. resembles species of Polycystis as well as of Paulodora. However, representatives of these two genera have a prostate stylet type I and a prostate vesicle type I. The prostate stylet type I in Polycystis is short and wide, with the distal rim of the outer stylet toothed [except in P. gabriellae (Marcus, 1948) Karling, 1952]. In Paulodora the outer stylet is rather elongated and complex, with folds and gutters, probably to drain the sperm. The prostate stylet of P. intermedia gen. n. sp. n. is (probably) of type II, as it is connected to a typical prostate vesicle of type II. It is rather long, but does resemble that of some species of Paulodora (e.g. P. subcontorta Schockaert, 1982) as to its general construction, i.e. with gutter-like folds, but without further ornamentations. Apart from the above-mentioned differences/resemblances in the construction of the stylet, P. intermedia gen. n. sp. n. lacks several of the typical, diagnostic features of the other two genera. Diagnostic features of species of Polycystis lacking in P. intermedia gen. n. sp. n. are the presence of accessory glands type I (also present in species of Paraustrorhynchus) and a large, asymmetrical, mostly excentric muscle bulb on the stalk of the male bursa (Artois & Schokaert 1998, 2003; Willems et al. 2006). The stalk of the male bursa is heavily muscular in P. intermedia gen. n. sp. n., but it is never asymmetrical, let alone excentric. Furthermore, the tick syncytial epithelium surrounding the internal vesicle of the male bursa in P. intermedia gen. n. sp. n. is not found in any species of Paulodora or Polycystis. Moreover, most of the species of Polycystis are darkly pigmented (Artois & Schockaert 1999), which is not the case in P. intermedia gen. n. sp. n.. Most species of Paulodora typically have elongated, kidney-shaped ovaries (see Artois & Tessens 2008), as is the case in P. intermedia gen. n. sp. n., but P. intermedia gen. n. sp. n. lacks the hard, umbrella-shaped "nozzles" at the connection between male bursa and each ovary that are so typical of species of Paulodora (Artois & Schockaert 1998). Moreover, in species of Paulodora the oviducts (mostly) merge with the male bursal tissue, and the ejaculatory duct makes a 270�� turn around the prostate vesicle before it ends in the male atrium next to the stylet. In P. intermedia gen. n. sp. n., the male bursal stalk is free, and the ejaculatory duct runs straight. A typical feature of P. intermedia gen. n. sp. n. is the presence of two bursae, a male and a female one, with the female bursa being large and with a long stalk. In species of Paulodora a female bursa is lacking, whereas in species of Polycystis it is very small (or absent, as in P. gabriellae) and almost without a stalk. Because of the issues discussed above, the new species cannot unambiguously be placed in any of the existing genera within Polycystididae, and, therefore, the erection of a new genus is warranted., Published as part of Diez, Yander L., Hern��ndez, Claudia Sanjuan, Reygel, Patrick, Roosen, Paulien & Artois, Tom, 2018, First record of Polycystididae (Platyhelminthes, Kalyptorhynchia) from Cuba, with the description of a new genus and five new species, and remarks and the description of one new species from Panama, pp. 107-125 in Zootaxa 4514 (1) on pages 117-120, DOI: 10.11646/zootaxa.4514.1.9, http://zenodo.org/record/2605858, {"references":["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. https: // doi. org / 10.1007 / BF 00408146","Karling, T. G. (1964) Uber einige neue und ungenugend bekannte Turbellaria Eukalyptorhynchia. Zoologischer Anzeiger, 172, 159 - 183.","Tessens, B., Janssen, T. & Artois, T. (2014) Molecular phylogeny of Kalyptorhynchia (Rhabdocoela, Platyhelminthes) inferred from ribosomal sequence data. Zoologica Scripta, 43 (5), 519 - 530. https: // doi. org / 10.1111 / zsc. 12066","Karling, T. G. (1952) Kalyptorhynchia (Turbellaria). Further Zoological Results of the Swedish Antarctic Expedition 1901 - 1903, 4 (9), 1 - 50.","Evdonin, L. A. (1970) A new genus of Turbellarians from the family Polycystididae. Zoological Journal, 49 (5), 781 - 784.","Graff, L. von (1905) Marine Turbellarien Orotavas und der Kusten Europas. Zeitschrift fur wissenschaftliche Zoologie, 83, 68 - 148.","Reisinger, E. (1926) Zur Turbellarienfauna der Antarktis. Deutsche Sudpolar-Expedition Zoologie, 18 (10), 417 - 463.","Sekera, E. (1901) Uber eine marine Art der Gattung Gyrator Ehrb. Zoologischer Anzeiger, 24, 79 - 81.","Artois, T. J. & Schockaert, E. R. (1999) Interstitial fauna of the Galapagos: Porrocystidinae (Plathelminthes, Polycystididae). Tropical Zoology, 12, 309 - 324. https: // doi. org / 10.1080 / 03946975.1999.10539397","Artois, T. J. & Schockaert, E. R. (2003) Primary homology assessment in the male atrial system of the Polycystididae (Platyhelminthes: Eukalyptorhynchia). Zoologischer Anzeiger, 242 (2), 179 - 190. https: // doi. org / 10.1078 / 0044 - 5231 - 00095","Karling, T. G. (1955) Studien uber Kalyptorhynchien (Turbellaria) 5. Der Verwandtschaftskreis von Gyratrix Ehrenberg. Acta Zoologica Fennica, 88, 1 - 39.","Karling, T. G. (1956) Morphologisch-histologische Untersuchungen an den mannlichen Atrialorganen der Kalyptorhynchia (Turbellaria). Arkiv for Zoologi, 9 (7), 187 - 279.","Schockaert, E. R. (1982) Turbellaria from Somalia 2. Kalyptorhynchia. Part 2. Monitore Zoologico Italiano, 18 (2), 81 - 96. https: // doi. org / 10.1080 / 03749444.1982.10736660","Willems, W. R., Schockaert, E. R. & Artois, T. J. (2006) Report on the Polycystididae (Rhabdocoela, Kalyptorhynchia) from Australia, with the description of twelve new species and six new genera. Hydrobiologia, 563, 329 - 355. https: // doi. org / 10.1007 / s 10750 - 006 - 0041 - 3","Artois, T. J. & Tessens, B. S. (2008) Polycystididae (Rhabditophora: Rhabdocoela: Kalyptorhynchia) from the Indian Ocean, with the description of twelve species. Zootaxa, 1849, 1 - 27."]}

Phonorhynchopsis capillaris Diez, Sanjuan, Reygel & Artois sp. n. (Fig. 1 D–F, 2G–H) Material and distribution in Cuba. Observations on two live specimens, whole mounted afterwards, one of them designated holotype (FMNH http://id.luomus.fi/ KV.602), the other one reference material (HU VIII.3.02), from El Masío (type locality) (June 30, 2016), intertidal, in very fine sand, upper 10 cm of the sediment, area with strong wave action, salinity 33 ‰. Etymology. The epithet capillaris refers to the general morphology of the accessory stylet, which is as thin as a hair (Lat. capillum = hair). Diagnosis. Species of Phonorhynchopsis with a prostate stylet type IV slightly bent in the middle, 57–60 µm long, 8–10 µm wide proximally and 5 µm subdistally, distal end rounded. Accessory stylet type IV slender, 284– 300 µm long, five times longer than the prostate stylet, proximally 10 µm wide, with the same width in the rest of the length (2 µm). Distally ending in a sharp tip, claw shaped. Description. Animals 0.9–1.2 mm long measured on the whole mounts. Body translucent; proboscis small, about 10% of the body length; a pair of pigmented eyes behind the proboscis. Pharynx in the middle of the body. Male copulatory structures organized as in P. haegheni. Prostate stylet type IV (Fig. 1D, 2H) slightly curved in the middle, 57–60 µm long, 8–10 µm wide proximally, 5 µm subdistally in both specimens, distally rounded. Accessory stylet type IV (Fig. 1 E–F, 2G) slender and slightly undulating, 284–300 µm long, 10 µm wide proximally, 2 µm wide in the middle and further distally. Sharp distal tip, claw shaped and preceded by a small dilatation in both specimens (Fig. 1F). Accessory gland type IV oval shaped and larger than the prostate gland, proximally connected with small extracapsular glands. Paired testes located behind the pharynx. Bursa bipartite. Paired vitellaria extending from the pharynx to the caudal end of the body. Discussion. See the Discussion after the description of P. sublinguatus sp. n.

Phonorhynchopsis haegheni (Artois & Schockaert, 2001) Willems & Artois, 2017 (in Willems et al. 2017) (Fig. 2 A���B) Material and distribution in Cuba. Observations on live animals. Eleven whole mounts (UH VIII.2.40��� VIII.2.50): one from Nicaro (January 28, 2016), intertidal in coarse sand, salinity 30 ���; one from Macab�� (April 23, 2017), intertidal, upper 10 cm of the fine sand, salinity 34 ���; eight from Siboney (February 7 & May 15, 2016, March 22 and June 5, 2017), intertidal up to 0.6 m depth, in fine sand with organic debris, salinity 32���35 ���; one from Chivirico (March 17, 2017), intertidal in very fine sand, salinity 35 ���. Remarks. In the specimens from Cuba the prostate stylet type IV (Fig. 2B) is 60���100 ��m long (x�� = 86 ��m; n = 11), 10���15 ��m wide proximally (x�� = 12 ��m; n = 10) and 3���6 ��m wide in the middle (x�� = 4 ��m; n = 10). The accessory stylet type IV (Fig. 2A) is 250���294 ��m long (x�� = 274 ��m; n = 11), 8���14 ��m wide proximally (x�� = 11 ��m; n = 11) and 4���8 ��m wide subdistally (x�� = 6 ��m; n = 11). The measurements of the specimens from Cuba are in the range of the specimens from Florida and Cura��ao, being longer than the specimens from Galapagos Islands and Indonesia (see Artois & Schockaert 2001; Artois & Tessens 2008)., Published as part of Diez, Yander L., Hern��ndez, Claudia Sanjuan, Reygel, Patrick, Roosen, Paulien & Artois, Tom, 2018, First record of Polycystididae (Platyhelminthes, Kalyptorhynchia) from Cuba, with the description of a new genus and five new species, and remarks and the description of one new species from Panama, pp. 107-125 in Zootaxa 4514 (1) on page 112, DOI: 10.11646/zootaxa.4514.1.9, http://zenodo.org/record/2605858, {"references":["Artois, T. J. & Schockaert, E. R. (2001) Interstitial fauna of the Galapagos: Duplacrorhynchinae, Macrorhynchinae, Polycystidinae, Gyratricinae (Plathelminthes, Polycystididae). Tropical Zoology, 14, 63 - 85. https: // doi. org / 10.1080 / 03946975.2001.10531143","Willems, W. R., Reygel, P., Van Steenkiste, N., Tessens, B. & Artois, T. J. (2017) Kalyptorhynchia (Platyhelminthes: Rhabdocoela) from KwaZulu-Natal (South Africa), with the description of six new species. Zootaxa, 4242 (3), 441 - 466. https: // doi. org / 10.11646 / zootaxa. 4242.3.2","Artois, T. J. & Tessens, B. S. (2008) Polycystididae (Rhabditophora: Rhabdocoela: Kalyptorhynchia) from the Indian Ocean, with the description of twelve species. Zootaxa, 1849, 1 - 27."]}

Phonorhynchopsis sublinguatus Diez, Sanjuan, Reygel & Artois sp. n. (Fig. 1 G���I, 2I���J) Material and distribution in Cuba. Observations on live animals. One specimen whole mounted, designated holotype (FMNH http://id.luomus.fi/ KV.603) from Macab�� (type locality) (April 23, 2017), in fine sand, 0.3���0.5 m depth, salinity 34 ���. Two whole mounts (HU VIII.3.03��� VIII.3.04) from Siboney (May 15, 2016 & March 22, 2017), one specimen from the intertidal, upper layer of the sand surface, and the other from the sublittoral, 0.6 m depth, salinity 32���35 ���. Etymology. The epithet refers to the resemblance of this species' prostate stylet to that of P. linguatus Artois & Tessens, 2008. Diagnosis. Species of Phonorhynchopsis with a prostate stylet type IV 76 ��m long, with the distal third widened, ending in a broad, rounded tip, being 35% of the length of the accessory stylet type IV. Accessory stylet type IV 219 ��m long, slightly undulate and tapering to a distal sharp tip. Description. Living animals about 1.2 mm long. General morphology of the organs resembles that of P. haegheni. Body translucent; proboscis small, about 10% of the body length; a pair of pigmented eyes behind the proboscis; pharynx at 50%. Prostate stylet type IV 75 ���77 ��m long (x�� = 76 ��m; n = 3), with a proximal flange 7���9 ��m wide (x�� = 8 ��m; n = 3); distal third widened up to 7���8 ��m (x�� = 7 ��m; n = 3), ending in a broad, rounded tip (Fig. 1G, 2J). Accessory stylet type IV 21 1 ���227 ��m long (x�� = 219 ��m; n = 3) with a proximally thickened short funnel 9���10 ��m wide (x�� = 9 ��m; n = 3), and distally a sharp tip, bent aside (Fig. 1 H���I, 2I). The general outline of the accessory stylet is symmetrically undulate in live animals. Stylet to stylet ratio (accessory stylet/prostate stylet) is 10/3.5. Bursa bipartite. Discussion. The two new species show the typical features of Phonorhynchopsis (see Willems et al. 2017): prostate stylet type IV rather broad and tubular, shorter than the accessory stylet type IV; bursa bipartite, consisting of a muscular and a sperm-resorbing part. Both new species described here differ from P. haegheni Artois & Schockaert, 2001 as to the relative length of the stylets and mainly in the shape of the prostate stylet (see Table 2). The length of the prostate stylet is only 20% of that of the accessory stylet in P. capillaris sp. n., whereas the same relative length is 35% in P. sublinguatus sp. n.. In P. haegheni the relative length of the prostate stylet is rather variable (21% in specimens from Galapagos Islands to 34% in the Atlantic populations). The prostate stylet of P. haegheni is the only one within the genus tapering from 12 ��m to 5 ��m, ending in a sharp distal tip (see Artois & Schockaert 2001). In P. capillaris sp. n. the prostate stylet tapers, but ends in a rounded tip, and in P. sublinguatus sp. n. the distal third is widened, very much resembling that of P. linguatus. However, the prostate stylet is smaller in P. sublinguatus sp. n. than in P. linguatus (Fig. 2 C��� D: reference material HU III.4.47 from Kenya), and the accessory stylet length is comparable with the specimen from Mah��, Seychelles (219 ��m) (see Artois & Tessens 2008). Therefore, the relative length of the prostate stylet in P. sublinguatus sp. n. (35% of the accessory stylet length) is lower than it is in the populations of P. linguatus (50% in Zanzibar, 65% in Seychelles and 65���71% in Kenya). The general morphology of the prostate stylet in P. sublinguatus sp. n. resembles that of P. linguatus, but the former species lacks the twist in the middle, a feature diagnostic of P. linguatus. One specimen of P. linguatus from Zanzibar (HU IV.1.17) (Figs. 2 E���F) is somewhat aberrant from the other specimens of the same species. Although the length of the prostate stylet is 50% that of the accessory stylet, as is the case in the holotype, which was collected in the same locality, the prostate stylet is not twisted in its midpart and its distal half is not markedly widened, hence more resembling that of P. sublinguatus sp. n.. The length of the prostate stylet in this specimen from Zanzibar is only 62% of that of the specimen of P. linguatus from Seychelles and �� 70% of that of the specimens from Kenya. The accessory stylet does not differ markedly in length between the different populations. Based on the shape and the absolute length of the stylets, it could be argued that specimen HU IV.1.17 of P. linguatus actually belongs to P. sublinguatus sp. n.. However, the relative length of the prostate stylet in this specimen is the same as in the holotype of P. linguatus (50%; 35% in P. sublinguatus sp. n.). Unfortunately, there is only one specimen that shows these features, which makes it impossible to decide whether this specimen belongs to P. linguatus, P. sublinguatus sp. n. or even another, yet undescribed species. In P. haegheni and P. linguatus, the length of the accessory stylet varies greatly between specimens, even of the same population (e.g. within the Galapagos population of P. haegheni). Its length seems to vary less in the other two species, but this could be because of the fact that only very few (two or three) specimens of each species are available. The absolute length of this stylet, hence, should be used with care in distinguishing or diagnosing species. The length of the accessory stylet is comparable between P. haegheni and P capillaris sp. n., showing some overlap. With a mean length of 292 ��m, the accessory stylet of P. capillaris sp. n. is somewhat larger than that of P. haegheni (258 ��m). The shortest accessory stylet is found in P. linguatus (mean length 189 ��m), but the length range overlaps with that of the accessory stylet of P. sublinguatus sp. n., which has a mean length of 219 ��m. The proximal and distal ends of the accessory stylet show subtle differences between the species. The walls of the proximal funnel-shaped part are markedly thickened in P. sublinguatus sp. n., which is not the case in the other three species. The extreme distal sharp tip is typically curved in P. capillaris sp. n. and P. sublinguatus sp. n., showing a small dilatation just proximal from the tip., Published as part of Diez, Yander L., Hern��ndez, Claudia Sanjuan, Reygel, Patrick, Roosen, Paulien & Artois, Tom, 2018, First record of Polycystididae (Platyhelminthes, Kalyptorhynchia) from Cuba, with the description of a new genus and five new species, and remarks and the description of one new species from Panama, pp. 107-125 in Zootaxa 4514 (1) on pages 112-114, DOI: 10.11646/zootaxa.4514.1.9, http://zenodo.org/record/2605858, {"references":["Artois, T. J. & Tessens, B. S. (2008) Polycystididae (Rhabditophora: Rhabdocoela: Kalyptorhynchia) from the Indian Ocean, with the description of twelve species. Zootaxa, 1849, 1 - 27.","Willems, W. R., Reygel, P., Van Steenkiste, N., Tessens, B. & Artois, T. J. (2017) Kalyptorhynchia (Platyhelminthes: Rhabdocoela) from KwaZulu-Natal (South Africa), with the description of six new species. Zootaxa, 4242 (3), 441 - 466. https: // doi. org / 10.11646 / zootaxa. 4242.3.2","Artois, T. J. & Schockaert, E. R. (2001) Interstitial fauna of the Galapagos: Duplacrorhynchinae, Macrorhynchinae, Polycystidinae, Gyratricinae (Plathelminthes, Polycystididae). Tropical Zoology, 14, 63 - 85. https: // doi. org / 10.1080 / 03946975.2001.10531143"]}

Polycydora Diez, Sanjuan, Reygel & Artois gen. n. Diagnosis. Polycystididae with a proboscis showing four pairs of proboscis retractors and a ventral pair of integument retractors. Ovaries, testes and vitellaria paired. With a prostate stylet type II connected to a prostate vesicle type II containing eosinophilic secretion. Stalk of the male bursa with a thick, symmetrical muscle layer. Ovaries elongate, kidney shaped. Female bursa well-developed, with a long stalk, ending at the junction of the two oviducts. Etymology. The name Polycydora is composed of Polycy-, taken from the genus Polycystis Kölliker, 1845, and of - dora, taken from the genus Paulodora Marcus, 1948, as the new genus shows some characters of both these genera. Type species. Polycydora intermedia sp. n., by monotypy.

Paraustrorhynchus elixus (Marcus, 1954) Karling & Schockaert, 1977 (Fig. 3 A���B) Material and distribution in Cuba. Four specimens studied alive and whole mounted (UH VIII.3.11��� VIII.3.14): two from Siboney (February 7, 2016 & April 4, 2017), one in very fine sand, 0.6 m depth, and the other on Ulva lactuca, 0.3 m deep; one specimen from Chivirico, on Halimeda sp. partially covered by organic matter, 0.6 m deep; one specimen from Las Sardinas, on Dictyota menstrualis partially covered by organic matter, 0.5 m depth. Salinity 32���35 ���. Remarks. According to Marcus (1954) the male sclerotized structures of P. elixus consist of three separate pieces: a small stylet connected to the prostate vesicle ("estilete da vesicula granulorum), a plate-like stylet associated with the ejaculatory duct ("estilete da vesicula seminais"), and an S-shaped plate ("flabelo"), to which a hook is connected ("flagelo"). Karling & Schockaert (1977), studying the original material of Marcus (1954), concluded that the plate-like stylet and the S-shaped plate are connected to each other, forming one complex structure. This view was followed by Artois & Tessens (2008), who consider the entire structure a prostate stylet type III, considering the small stylet connected to the prostate vesicle type II as a prostate stylet type II. However, the new material collected in Cuba clearly shows that the complex accessory copulatory organ (the "prostate stylet type III") indeed consists of two separate structures: the stalk and the S-shaped plate with a hook. Both structures are only connected proximally by a muscular bulb, as was mentioned by Marcus (1954). In several specimens both structures lie on top of each other, making it extremely difficult to observe that they are separated. In live animals, however, as well as in more lightly-squeezed whole mounts, it is obvious that both structures are indeed separated. At the moment it is impossible to determine what are the exact homologies of the two parts, i.e. which of the two parts, if any, corresponds to the prostate stylet type III of other species of Polycystidinae. Because of its close association with the ejaculatory duct, it could be deduced that the "stalk" actually is the prostate stylet type III and that the S-shaped plate with a hook is either a newly-formed structure, or is a part that in the course of evolution has come loose from the stalk. This, of course, is all highly speculative. The only other species within Polycystidinae that has three stylets is Triaustrorhynchus armatus Willems, Schockaert & Artois, 2006, which has a prostate stylet type II, a prostate stylet type III and an accessory stylet type III (Willems et al. 2006), but the accessory stylet in this species is in a much more distal position in the male atrium and is associated with a glandular vesicle of its own. Therefore, it is doubtful that T. armatus and P. elixus are very closely related. The above suggests that P. elixus does not belong to the same genus as the other species of Paraustrorhynchus, which currently includes three other species that typically have two stylets only. However, we prefer not to create a separate, new genus for P. elixus before molecular data affirms this decision. As to morphology, the prostate stylet type II in the specimens from Cuba is as described by Schockaert & Karling (1977) and Artois & Tessens (2008) for the specimens of other areas. It is 31���37 ��m long (x�� = 35 ��m; n = 4) (Fig. 2 A���B: ps2), which fits the range recorded up to now (see Artois & Tessens 2008): 27 ��m (specimen from New Caledonia) ��� 33 ��m (specimen from Brazil). As mentioned above, the "prostate stylet type III" actually consists of two separated parts: a long, somewhat slender "stalk" and an S-shaped plate with a hook. In the specimens from Cuba the stalk is 76���84 ��m long (x�� = 80 ��m; n = 4) (Fig. 3 A���B: sk), the S-shaped plate is 63���78 ��m long (x�� = 70 ��m; n = 4) (Fig. 3 A���B: spl), and the hook is 13���23 ��m long (x�� = 18 ��m; n = 4) (Fig. 3 A���B: h). These measurements correspond to the measurements given by Artois & Tessens (2008) for the other populations of this species., Published as part of Diez, Yander L., Hern��ndez, Claudia Sanjuan, Reygel, Patrick, Roosen, Paulien & Artois, Tom, 2018, First record of Polycystididae (Platyhelminthes, Kalyptorhynchia) from Cuba, with the description of a new genus and five new species, and remarks and the description of one new species from Panama, pp. 107-125 in Zootaxa 4514 (1) on page 115, DOI: 10.11646/zootaxa.4514.1.9, http://zenodo.org/record/2605858, {"references":["Marcus, E. (1954) Turbellaria Brasileiros (11). Papeis Avulsos do Departamento de Zoologia Secretaria da Agricultura Sao Paulo, 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. https: // doi. org / 10.1111 / j. 1463 - 6409.1977. tb 00755. x","Artois, T. J. & Tessens, B. S. (2008) Polycystididae (Rhabditophora: Rhabdocoela: Kalyptorhynchia) from the Indian Ocean, with the description of twelve species. Zootaxa, 1849, 1 - 27.","Willems, W. R., Schockaert, E. R. & Artois, T. J. (2006) Report on the Polycystididae (Rhabdocoela, Kalyptorhynchia) from Australia, with the description of twelve new species and six new genera. Hydrobiologia, 563, 329 - 355. https: // doi. org / 10.1007 / s 10750 - 006 - 0041 - 3"]}

Phonorhynchoides minor Diez, Sanjuan, Reygel & Artois sp. n. (Fig. 1 A–C) Material and distribution in Cuba. Two specimens studied alive and whole mounted afterwards, one of which designated holotype (FMNH http://id.luomus.fi/ KV.601), the other one reference material (HU VIII.2.39). Both specimens were collected in Siboney (type locality) (February 7, 2016 & June 5, 2017), the holotype on Gracilaria sp., 0.5 m deep, salinity 32 ‰; the other specimen in the upper layer of fine sand in the intertidal, salinity 35 ‰. Etymology. The epithet reflects the fact that the new species has the smallest stylets of all species in the genus (Lat. minor = smaller). Diagnosis. Species of Phonorhynchoides with a slightly curved prostate stylet type IV, proximally rounded and distally obliquely cut, 53–58 µm long, 4 µm wide. Accessory stylet type IV 45 µm long, 3 µm wide proximally, twisted distally, tapering into a distal sharp tip. Description. Living animals 1 mm long, with a pair of eyes and a translucent body. Proboscis 1/10 to 1/12 of the body length (Fig. 1A: pr), and pharynx situated at about 25% (Fig. 1A: ph). General internal morphology as in other species of the genus. Atrial organs in the posterior two-thirds of the body. Paired testes caudally from the pharynx (Fig. 1A: t). Prostate vesicle type IV spindle shaped (Fig. 1A: pv4), with only one type of secretion visible in live animals. Prostate stylet type IV (Fig. 1A: ps4, Fig. 1B) slightly curved, 53–58 µm long and 4 µm wide, proximally rounded and with a subterminal distal opening. Accessory vesicle type IV (Fig. 1A: av4) rounded and connected to a straight accessory stylet type IV (Fig. 1A: as4, Fig. 1C), which in both specimens is 45 µm long and 3 µm wide proximally. It tapers to a sharp distal tip, showing a twist just proximal from this tip. Accessory stylet to prostate stylet ratio is 80%. Paired vitellaria (Fig. 1A: vi) extend at both sides of the body, from behind the proboscis to the end of the body. Small oval ovaries are present in the midbody (Fig. 1A: ov), with the oocytes in a row. Globular bursa not bipartite (Fig. 1A: fb), posterolateral to the male sclerotized organs and connected to the common genital atrium (Fig. 1A: cga) through a sphincter (Fig. 1A: sph). Distal to the sphincter, the common genital atrium receives the male genital duct. Common gonopore at approximately 90% (Fig. 1A: cg). Discussion. The new species shows the typical features of Phonorhynchoides (as diagnosed by Willems et al. 2017): male system with two stylets, a prostate stylet type IV and an accessory stylet type IV, the prostate stylet being longer than the accessory stylet, and a bursa that is not bipartite (as opposed to that of Phonorhynchopsis Willems & Artois, 2017). In P. flagellatus Beklemischev, 1927 and P. japonicus Ax, 2008 the prostate stylet is more or less straight, as it is in P. minor sp. n., but in P. minor sp. n. it is ± 3 times shorter than in the other two species. In the remaining species of the genus (P. carinostylis Ax & Armonies, 1987, P. gondwanae Willems & Artois, 2017, and P. somaliensis Schockaert, 1971), the prostate stylet shows a typical undulation (P. carinostylis and P. gondwanae) or is corkscrew-shaped in its midpart (P. somaliensis). In these three species, the prostate stylet is 3.5 to 4.8 times longer than it is in P. minor sp. n.. The prostate stylet of P. minor sp. n. does not show ornamentations, which are present in the prostate stylet type IV of P. carinostylis (spiral ridge over whole length) and P. japonicus (short spiral ridge). A unique feature of P. minor sp. n. within the genus is the oblique distal end of the prostate stylet. In all the other species the prostate stylet ends in a sharp point. The accessory stylet type IV of the described species in the genus is 1.7 (in P. carinostylis and P. flagellatus) to 2.5 (in P. gondwanae) times longer than it is in P. minor sp. n.. The relative length of the accessory stylet compared to the prostate stylet in P. minor sp. n. is the highest in the genus (82%), compared with 74% in P. japonicus, 45– 55% in P. somaliensis, 50% in P. flagellatus, 42–46% in P. gondwanae, and 33–36% in P. carinostylis (see Willems et al. 2017).

Gyratrix Ehrenberg, 1831 Gyratrix hermaphroditus Ehrenberg, 1831 species complex Material and distribution in Cuba. Observations on live animals. Thirty-seven specimens whole mounted: one from Macab�� (April 23, 2017), four from Nicaro (January 28, 2016 & March 10, 2016), one from Las Sardinas (June 24, 2016), one from El Guaimaral (June 23, 2016), one from Bah��a Larga (April 5, 2017), two from Bah��a de Santiago de Cuba (February 28, 2016 & January 31, 2017), 15 from Aguadores (January 24, 2017 & February 14, 2017), and 12 from Siboney (February 7, 2016, May 16, 2016, March 22, 2017 & April 4, 2017). The species was found in a wide range of habitats including sandy and sandy-muddy bottoms, from the intertidal to 1 m depth. Furthermore, the species was collected on algae (Ulva lactuca, U. flexuosa and Gracilaria sp.) and seagrass (Thalassia testudinum), in salinity range of 25���35 ���. Remarks. The fact that G. hermaphroditus is a species complex consisting of dozens of cryptic species is very well known (see Curini-Galletti & Puccinelli 1990, 1994, 1998; Artois & Schockaert 2001; Artois & Tessens 2008). The specimens collected in Cuba show differences in length and detailed morphology of the stylets, and in the shape of the ovaries (kidney or globular shaped), corresponding to 10 morphospecies. Considering the taxonomic complexity of the genus, we prefer to wait for DNA studies to fully describe these species., Published as part of Diez, Yander L., Hern��ndez, Claudia Sanjuan, Reygel, Patrick, Roosen, Paulien & Artois, Tom, 2018, First record of Polycystididae (Platyhelminthes, Kalyptorhynchia) from Cuba, with the description of a new genus and five new species, and remarks and the description of one new species from Panama, pp. 107-125 in Zootaxa 4514 (1) on pages 109-110, DOI: 10.11646/zootaxa.4514.1.9, http://zenodo.org/record/2605858, {"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.","Curini-Galletti, M. C. & Puccinelli, I. (1990) The Gyratrix hermaphroditus Species Complex (Plathelminthes: Kalyptorhynchia) in the Darwin Area (Northern Territory, Australia). Transactions of the American Microscopical Society, 109 (4), 368 - 379. https: // doi. org / 10.2307 / 3226691","Curini-Galletti, M. C. & Puccinelli, I. (1994) The Gyratrix hermaphroditus species-complex (Platyhelminthes kalyptorhynchia) in marine tropical areas: first data from the Caribbean. Belgian Journal of Zoology, 124 (2), 157 - 166.","Curini-Galletti, M. C. & Puccinelli, I. (1998) The Gyratrix hermaphroditus species complex (Kalyptorhynchia: Polystididae) in marine habitats of eastern Australia. Hydrobiologia, 383, 287 - 298. https: // doi. org / 10.1023 / A: 1003456102035","Artois, T. J. & Schockaert, E. R. (2001) Interstitial fauna of the Galapagos: Duplacrorhynchinae, Macrorhynchinae, Polycystidinae, Gyratricinae (Plathelminthes, Polycystididae). Tropical Zoology, 14, 63 - 85. https: // doi. org / 10.1080 / 03946975.2001.10531143","Artois, T. J. & Tessens, B. S. (2008) Polycystididae (Rhabditophora: Rhabdocoela: Kalyptorhynchia) from the Indian Ocean, with the description of twelve species. Zootaxa, 1849, 1 - 27."]}

Kalyptorhynchia Graff, 1905 Eukalyptorhynchia Meixner, 1928, Published as part of Diez, Yander L., Hern��ndez, Claudia Sanjuan, Reygel, Patrick, Roosen, Paulien & Artois, Tom, 2018, First record of Polycystididae (Platyhelminthes, Kalyptorhynchia) from Cuba, with the description of a new genus and five new species, and remarks and the description of one new species from Panama, pp. 107-125 in Zootaxa 4514 (1) on page 109, DOI: 10.11646/zootaxa.4514.1.9, http://zenodo.org/record/2605858, {"references":["Graff, L. von (1905) Marine Turbellarien Orotavas und der Kusten Europas. Zeitschrift fur wissenschaftliche Zoologie, 83, 68 - 148.","Meixner, J. (1928) Aberrante Kalyptorhynchia (Turbellaria: Rhabdocoela) aus dem Sande der Kieler Bucht. Zoologischer Anzeiger, 77, 229 - 253."]}

Stem cells or undifferentiated cells can cope more easily with external stresses. To evaluate the impact of toxic compounds on stem cell dynamics in vivo, in relation to other biological responses, we use the carcinogenic element cadmium and the regenerating model organism Macrostomum lignano. Through both BrdU and anti-histone H3 immunostainings, cadmium-induced effects were investigated at different stages of the stem cell cycle. A 24-h exposure to 100 and 250 M CdCl2 significantly decreased the number of stem cells (neoblasts) in mitosis, whereas the number of cells in the S phase remained unchanged. After this short-term exposure, the ultrastructure of the neoblasts was minimally affected in contrast to the epidermal tissues. These results were supported by gene expression data: transcripts of cdc2 and pig3 were significantly upregulated during all treatments. Both genes are involved in the cell cycle progression and are transcribed in the gonadal region, where stem cells are highly represented. Based on a substantial increase in gene expression of heat shock proteins (HSP) and their high activity in the gonadal region, we hypothesize that these proteins are key players in the protection of stem cells against external stresses. Apart from the strong HSP induction, other protective processes including cell division, apoptosis and anti-oxidative defence, were also activated. We, therefore, conclude that the protection of stem cells against external stressors may be based on the interplay between stem cell maintenance, i.e. repair and recovery through division, on one hand and apoptosis on the other hand. (c) 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1217-1228, 2016.

Research Infrastructures (RIs) are facilities, resources and services used by the scientific community to conduct research and foster innovation. LifeWatch ERIC has developed various virtual research environments, which include many virtual laboratories (vLabs) offering high computational capacity and comprehensive collaborative platforms that supporting the needs of digital biodiversity science. Over its 250 years of history, the taxonomic research community has developed a system for describing, classifying and naming taxa across multiple levels. For the marine biota, taxonomic information is organized and made publicly available through the World Register of Marine Species (WoRMS) that records more than 250,000 described valid species. Although scientists tend to assign an equal status (in terms of contribution to overall diversity) to each taxon used in taxonomy, biogeography, ecology and biodiversity, the question “are all taxa equal?” has never been tested at a global scale. We present evidence that this question can be addressed by applying relatedness indices (Taxonomic Distinctness) over the entire WoRMS metazoan tree. The RvLab, developed by the LifeWatchGreece RI, operating on a high-performance computer cluster, has been used to meet the high computational demands required for such an analysis at a global scale.

International audience; The Lower Congo Basin is characterized by a mangrove-lined estuary at its mouth and, further upstream, by many hydrogeographical barriers such as rapids and narrow gorges. Five localities in the mangroves and four from (upstream) left bank tributaries or pools were sampled. On the gills of Coptodon tholloni, Coptodon rendalli, Hemichromis elongatus, Hemichromis stellifer and Tylochromis praecox, 17 species of parasites (Dactylogyridae & Gyrodactylidae, Monogenea) were found, eight of which are new to science. Six of these are herein described: Cichlidogyrus bixlerzavalai n. sp. and Cichlidogyrus omari n. sp. from T. praecox, Cichlidogyrus calycinus n. sp. and Cichlidogyrus polyenso n. sp. from H. elongatus, Cichlidogyrus kmentovae n. sp. from H. stellifer and Onchobdella ximenae n. sp. from both species of Hemichromis. On Cichlidogyrus reversati a ridge on the accessory piece was discovered that connects to the basal bulb of the penis. We report a putative spillback effect of the native parasites Cichlidogyrus berradae, Cichlidogyrus cubitus and Cichlidogyrus flexicolpos from C. tholloni to the introduced C. rendalli. From our results, we note that the parasite fauna of Lower Congo has a higher affinity with the fauna of West African and nearby freshwater ecoregions than it has with fauna of other regions of the Congo Basin and Central Africa.; Le cours du Bas Congo est caractérisé par un estuaire bordé de mangroves et, plus en amont, par de nombreuses barrières hydro-géographiques formées de rapides ou de gorges étroites. Nous avons échantillonné dans cinq localités au niveau des mangroves et dans quatre autres en amont sur la rive gauche du fleuve, dans des affluents ou des étangs. Nous avons trouvé, sur les branchies de Coptodon tholloni, Coptodon rendalli, Hemichromis elongatus, Hemichromis stellifer et Tylochromis praecox, 17 espèces de parasites (Dactylogyridae et Gyrodactylidae, Monogenea), dont huit sont nouvelles pour la science. Six d’entre elles sont décrites ici : Cichlidogyrus bixlerzavalai n. sp. et Cichlidogyrus omari n. sp. sur T. praecox, Cichlidogyrus calycinus n. sp. et Cichlidogyrus polyenso n. sp. sur H. elongatus, Cichlidogyrus kmentovae n. sp. sur H. stellifer et Onchobdella ximenae n. sp. sur les deux espèces d’Hemichromis. Nous décrivons, chez Cichlidogyrus reversati, une arête sur la pièce accessoire qui la connecte avec l’ampoule basale basal du pénis. Nous notons un probable transfert latéral des espèces autochtones Cichlidogyrus berradae, Cichlidogyrus cubitus et Cichlidogyrus flexicolpos de C. tholloni vers l’espèce introduite C. rendalli. Nos résultats montrent que la faune parasitaire du Bas Congo présente plus d’affinités avec les faunes d’Afrique de l’Ouest ou des écorégions d’eau douce voisines, qu’avec celles des autres parties du bassin du Congo ou de l’Afrique Centrale.