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Polysyncraton purou C. Monniot & F. Monniot, 1987 Fig. 10 Polysyncraton purou C. Monniot & F. Monniot, 1987: 49, fig. 16d���h, pl. 3i. Polysyncraton purou ��� F. Monniot 1993: 11. ��� Kott 2001: 126, figs 60, 162C, pl. 6F; 2002: 33, fig. 12A��� D; 2005: 2436, fig. 19D. Material examined TANZANIA ��� 3 slides; MNHN A2-843, MNHN A2-846, MNHN A2-847. Remarks This species was described from French Polynesia by C. Monniot & F. Monniot (1987). All the characteristics of the specimens from Tanzania correspond to those in the original description (Fig. 10), thus enlarging the known distribution of this species. Monniot & Monniot (2001) described P. vestiens from Palau as a different species from P. purou based on the smaller spicules, a wider atrial aperture and the absence of the muscular process in P. vestiens. However, in the specimens from Tanzania there is a variation in the size of the spicules and they are smaller (43 to 55 ��m) than in specimens from Tahiti. The muscular process in P. purou is very small and not visible in some zooids (Fig. 10 a���b). Since the size of the atrial aperture is also a variable character that depends on the contraction of the zooid, there is doubt as to whether P. vestiens is a valid species. Distribution Type locality: French Polynesia (C. Monniot & F. Monniot 1987). Australia (Kott 2001), New Caledonia (F. Monniot 1993) and Tanzania (this study)., Published as part of Oliveira, Livia M., Hoeksema, Bert W. & Rocha, Rosana M., 2019, Polysyncraton (Ascidiacea, Didemnidae): a re-examination of some specimens and descriptions of three new species, pp. 1-25 in European Journal of Taxonomy 519 on page 17, DOI: 10.5852/ejt.2019.519, http://zenodo.org/record/2650112, {"references":["Monniot C. & Monniot F. 1987. Les ascidies de Polynesie francaise. Memoires du Museum national d'Histoire naturelle, Zoologie 136: 1 - 155.","Monniot F. 1993. Ascidies de Nouvelle-Caledonie XIII. Le genre Polysyncraton. Bulletin du Museum national d'Histoire naturelle, 4 ieme serie 15 ª (1 - 4): 3 - 17.","Kott P. 2001. The Australian Ascidiacea. Part 4, Aplousobranchia (3), Didemnidae. Memoirs of the Queensland Museum 47 (1): 1 - 410. Available from https: // biodiversitylibrary. org / page / 40460926 [accessed 20 Jul. 2018].","Monniot C., Monniot F., Griffiths C. L. & Schleyer M. 2001. South African ascidians. Annals of the South African Museum 108 (1): 1 - 141. Available from https: // biodiversitylibrary. org / page / 40905473 [accessed 20 Jul. 2018]."]}

Polysyncraton sp. Fig. 12 Material examined BRAZIL ��� 1 colony; Rio de Janeiro, Cabo Frio, Pargos Island, Enseada do Pinguim; 22��51���10��� S, 41��54���22��� W; ~ 10 m depth; 7 May 2014; L.F. Skinner leg.; DZUP POSC-033, slide DZUP DID5.29. Remarks The colony is orange in situ, measuring 3 cm in diameter and 1 to 2 mm thick. The tunic is firm and gelatinous. The cloacal aperture has five lobes. The spicules are distributed in the colony surface only and are more concentrated around the oral siphon of each zooid. They are burr-like, with a large number of rays, 15 to 25 ��m in diameter. The zooids are orange. The oral siphon is short, with six triangular lobes. The atrial aperture is wide, exposing almost all the pharynx, with 9, 9, 8, 8���7 stigmata per half row. The atrial languet is large and bifurcated. The lateral thoracic organ is circular, not protruding, located at the level of the 1 st row of stigmata. The muscular process is shorter than the abdomen, inserted in the middle of the esophageal peduncle. The testis is divided in four follicles surrounded by four coils of the sperm duct. Larvae were not found. In the phylogenetic reconstruction (Fig. 5), this species (UPDID096-17) is separate from P. amethysteum, from which it differs by the colour of the colony, lobed cloaca and the position of the lateral thoracic organ. Lotufo (2002) reported orange specimens from Rio de Janeiro and Esp��rito Santo, but we were able to examine the sample from Angra dos Reis and concluded that Lotufo���s sample (ColBio Tun 1245) actually belongs to the genus Leptoclinides Bjerkan, 1905. This species differs from P. cabofriense sp. nov., by the colour of the colony, the abundance, shape and position of the spicules, and in having more follicles and coils of the sperm duct. Given the single colony found and lack of larvae we prefer not to name it, although characters suggest that it is an undescribed species. Distribution Brazil: Rio de Janeiro (this study)., Published as part of Oliveira, Livia M., Hoeksema, Bert W. & Rocha, Rosana M., 2019, Polysyncraton (Ascidiacea, Didemnidae): a re-examination of some specimens and descriptions of three new species, pp. 1-25 in European Journal of Taxonomy 519 on pages 19-22, DOI: 10.5852/ejt.2019.519, http://zenodo.org/record/2650112, {"references":["Lotufo T. M. C. 2002. Ascidiacea (Chordata: Tunicata) do litoral tropical brasileiro. PhD Thesis. Instituto de Biociencias da Universidade de Sao Paulo, Brazil."]}

Polysyncraton globosum Oliveira & Rocha sp. nov. urn:lsid:zoobank.org:act: 1BF4A55D-4A94-4598-8BC0-4A26E33EF5DD Fig. 7 Didemnum (Polysyncraton) magnetae – Millar 1963: 702 (misidentification, not Hastings, 1931). Etymology The name refers to the shape of the colony. Material examined Holotype AUSTRALIA • 1 colony; Bowerbank leg.; NHM 1866.3.21.21, slides NHM 1866.3.21.21, DZUP DID 5.12. Paratype AUSTRALIA • 1 colony; Bowerbank leg.; NHM 1866.3.21.20, slide NHM 1866.3.21.20. Description The species is characterised by its globular colonies, 3.5 cm at maximum length (Fig. 7a). The tunic is gelatinous and the colony surface is smooth. The spicules are distributed in low density, mainly on the colony surface. Just one cloacal aperture with a smooth edge was observed in each colony. The globular spicules are 20 to 30 µm in diameter and have numerous thin rays (16 to 18 rays in optical transverse section) (Fig. 7b). The thorax has 12 conspicuous muscle bundles on each side (Fig. 7c). The oral siphon has six triangular lobes. The atrial languet is bifurcated but was lost in some thoraces when the zooids were dissected. The lateral thoracic organ is circular, not protruding, located at the level of the 1 st row of stigmata, in the middle of the thorax (Fig. 7c). The second gut loop does not overlay the stomach. The testis is divided in six follicles surrounded by two or three coils of the sperm duct (Fig. 7d), although the description by Millar (1963) mentioned up to eight follicles. Larvae are elliptical, the trunk 1.0 to 1.3 mm long (Fig. 7e). The tail winds about ¾ of the way around the trunk. At the left side of the larva, it is possible to see a wide membrane projecting from the sides of the tail (Fig. 7f). The three adhesive papillae with long and thin peduncles are close together and there are eight pairs of rectangular ectodermal ampullae. The sensory vesicle is in the central region of the larval trunk, with the ocellus and estatocyte close together. The larva is not gemmiparous. Remarks These Australian specimens, which were deposited at the Natural History Museum in London, have previously been identified as P. magnetae Hastings, 1931 by Millar (1963). The sample NHM 1930.12.17.46 from the Great Barrier Reef, Stat. XXIII, R/V “Magneta”, collected on 12 Mar. 1929 is part of the type series of P. magnetae and was re-examined (Fig. 8). Although also looking globular, the colony is not as solid as in P. globosum sp. nov. and has a high density of spicules in the tunic, with cylindrical rays of a larger diameter and in a smaller number than in P. globulosum (Fig. 8). The atrial languet in P. magnetae is almost imperceptible, short and pointed, and could be missed during dissection, although Hastings (1931) described it as large. Unfortunately, the larva of P. magnetae is not known for comparison with congeneric species. Kott (2001) also realised that Millar’s identification was wrong and suggested that the NHM material belonged to P. meandratum F. Monniot, 1993. We do not agree with this suggestion because P. meandratum has thin and sheet-like colonies, an atrial languet larger than those observed in P. globosum sp. nov., less male follicles and a larva less than half the size of that of P. globosum sp. nov. (F. Monniot 1993). Distribution Type locality: Australia (Millar 1963).

Polysyncraton Nott, 1892 is the second largest genus of didemnid ascidians; it has a wide distribution ranging from temperate to tropical waters. Seventy-one specimens of Polysyncraton from eight museum collections and recently collected samples were analyzed. This resulted in the description of three new species (P. cabofriense Oliveira & Rocha sp. nov. from Brazil, P. globosum Oliveira & Rocha sp. nov. from Australia and P. snelliusi Oliveira & Rocha sp. nov. from Suriname) and emended descriptions of three further species (P. amethysteum (Van Name, 1902), P. magnilarvum (Millar, 1962) and P. purou C. Monniot & F. Monniot, 1987).

Polysyncraton snelliusi Oliveira & Rocha sp. nov. urn:lsid:zoobank.org:act: 650A74FA-077A-46B4-B1EF-9BF5CC2B44E6 Fig. 11 Etymology The name refers to the campaign vessel that collected the material. Material examined Holotype SURINAME • 1 colony; Guiana Shelf, stat. 97; 07°16.8′ N, 56°47.6′ W; 64 m depth; 13 Apr. 1966; HNLMS Snellius leg.; Onderzoek Continentaal Plat Suriname (OCPS); RMNH.UROCH.1109. Description The colony is yellowish in preserved material, measuring 8 cm in diameter and 2 mm thick. It has an irregular shape, molding itself on top of a sponge. The colony surface has several common cloacal apertures with six to eight short lobes each (Fig. 11b). The cloacal cavity is wide and positioned at the thoracic level. The tunic is firm, brittle and with many papillae associated with one of the lobes of the oral siphons. The zooids form circular systems around the cloaca and also linear systems along the cloacal channels, which are marked by a depression on the colony surface. They have a brown colour, leaving white circular or irregular patches on the colony surface (Fig. 11c). Two types of stellate spicules are distributed in the tunic. The larger ones (40 to 60 µm in diameter) have six rays in transverse optical section, but many other shorter rays among the main ones. Also, the rays are either blunt or more pointed. The smaller spicules (23 to 50 µm in diameter, a few to 60 µm), have seven to eight conical rays with round tips in transverse optical section, without intermediate rays (Fig. 11d). The zooids are 1.0 mm long. The oral siphon is short (0.2 mm), with six long triangular lobes. The atrial aperture is wide, exposing almost all the pharynx, without an atrial languet. The pharynx stigmata formula is 12, 12, 11, 9. The lateral thoracic organs are circular, not protruding and localised at the level of the 2 nd row of stigmata. The muscular process is lacking. The esophageal peduncle is short and straight. The testis is divided in four follicles surrounded by three coils of the sperm duct. The secondary gut loop does not overlay the stomach (Fig. 11e). The larvae are elliptical, not gemmiparous, with the trunk 0.8 to 0.9 mm long. A tail with a diameter of 116 µm winds halfway around the trunk. The sucker of the central adhesive papilla is 95 µm in diameter and the peduncle is 235 µm long. There are 12 to 14 elongated, thin ectodermal ampullae on each side of the larva, 105 to 120 µm long (Fig. 11f). The sensorial vesicle (including ocellus and statocyte) is slightly posterior to the mid-dorsal region of the larval trunk. The ocellus is 54 µm long and 361 µm distant from the anterior region of the tail. Remarks Eight species of Polysyncraton have been reported from the Atlantic Ocean (Rocha et al. 2012; Paiva et al. 2015) and none of them look like the one described herein. Polysyncraton snelliusi sp. nov. can be distinguished from P. cabofriense sp. nov. by the absence of papillae on the colony surface and the presence of gemmiparous larvae in the latter. Among other species with papillae on the colony surface, P. echinatum Kott, 2001 has a gelatinous tunic, stellate spicules without secondary rays and smaller larvae (trunk 0.6 mm long), with four subdividing ectodermal ampullae on each side; P. meandratum F. Monniot, 1993 has globular spicules with flat-tipped rays, a bifurcated atrial languet and larvae with eight pairs of ectodermal ampullae; P. pseudorugosum F. Monniot, 1993 has stellate spicules with sharp pointed rays and deeper common cloacal canals, seven testis follicles and smaller larvae with eight pairs of ectodermal ampullae. Distribution Type locality: Suriname (Guyana Shelf).

Polysyncraton cabofriense Oliveira & Rocha sp. nov. urn:lsid:zoobank.org:act: 356E2138-BAED-47B4-8E06-8182B064EB7B Fig. 6 Etymology The name refers to the region where the species was found. Material examined Holotype BRAZIL • 1 colony; Rio de Janeiro, Cabo Frio, Pargos Island, Enseada do Pinguim; 22°51′10″ S, 41°54′22″ W; ~ 10 m depth; 7 May 2014; L.F. Skinner leg.; scuba; DZUP POSC-50, slide DZUP DID5.02. Paratypes BRAZIL • 2 colonies; same collecting data as for holotype; DZUP POSC-46, DZUP POSC-49, slide DZUP DID5.05 • 2 colonies; Comprida Island, Ponta Leste; 22°51′41″ S, 41°56′12″ W; ~ 8 m depth; 6 May 2014; L.F. Skinner leg.; DZUP POSC-47, DZUP POSC-48, slides DZUP DID5.03, DZUP DID5.04. Description Living colonies are yellowish, with a diameter of 3 to 15 cm and a thickness of 2 to 3 mm. When preserved in formalin, colonies usually lose their colour and become cream coloured, sometimes white. They have an irregular shape, molding themselves to the substrate. The colony surface has several common cloacal apertures, each one with short lobes (Fig. 6 a–b). The tunic is firm, brittle and smooth. Green algae were observed on the surface of some colonies. Spicules are distributed in the whole tunic, with relatively high concentrations on each side of the thorax at the level of the lateral thoracic organ. There are two kinds of spicules: stellate, 32 to 40 µm in diameter, with 6 or 7 blunt-tipped conical rays in transverse optical section; others are smaller (25 to 28 µm in diameter), with round and short rays (Fig. 6c). Zooids are 0.8 to 1.0 mm long. The oral siphon has six small triangular lobes. The atrial aperture is wide, exposing most of the pharynx. The atrial languet is pointed and thin (Fig. 6d) or wide and rounded. In some specimens it was absent, probably lost during dissection. The lateral thoracic organs are circular, not protruding and localised between the first and second rows of stigmata on the border of the atrial aperture. The pharynx has seven stigmata in the first two half rows and six stigmata on the posterior two half rows. The muscular process is lacking. The testis is divided in three oval follicles surrounded by three coils of the sperm duct. The oocyte is single, measuring 0.6 mm. The larvae are elliptical, gemmiparous, the trunk measuring 0.9 to 1.0 mm. A tail with a diameter of 95 µm winds about ¾ of a turn around the trunk. The three adhesive papillae show a short and wide peduncle. The sucker of the central adhesive papilla is 124 µm in diameter. There are 10 pairs of rounded ectodermal ampullae. The ocellus is 45 µm long and 346 µm distant from the anterior region of the tail. Remarks Only two species of Polysyncraton have been reported from Brazil, P. amethysteum with a distribution along the whole coastline and P. maurizelae Paiva et al., 2015 from Rocas Atoll (Paiva et al. 2015). Polysyncraton cabofriense sp. nov. differs from P. amethysteum by its colour, higher density of spicules, lobed cloaca and larvae with more pairs of ectodermal ampullae. Polysyncraton maurizeliae has orange colonies with smooth common cloacal apertures, zooids longer and with 12 stigmata in the 1 st row, and the lateral thoracic organ in the 3 rd row. Among other species from the Atlantic, P. louminae F. Monniot, 1984 has a colony of similar shape and spicules, but the colony is grey, zooids have longer oral siphons and two testis follicles surrounded by 3 to 5 coils of the sperm duct, and the larvae are not gemmiparous and have more pairs of ectodermal ampullae (F. Monniot 1984). Distribution Type locality: Brazil (Rio de Janeiro).

Polysyncraton amethysteum (Van Name, 1902) Figs 2–5 Polysyncraton amethysteum Van Name 1902: 366, pl. 54, figs 62, 64–67. Polysyncraton amethysteum – Rodrigues 1962: 195. — Millar 1977: 200, fig. 21. — Rocha et al. 2005: 467. — Lotufo & Silva 2006: 228. — F. Monniot 2016: 207, fig. 4D. Didemnum (Polysyncraton) amethysteum – Van Name 1921: 333, figs 27–29; 1945: 95, fig. 41, pl. 18, fig. 3. — Moure et al. 1954: 236. — Millar 1958: 499. Material examined Paratype BERMUDA • 1 colony; NHM 1914.5.18.103. Other material BRAZIL – Paraíba • 4 colonies; Barra de Camaratuba; 06°36′12″ S, 34°57′51″ W; 0–0.3 m depth; 13 Mar. 2013; L. M. Oliveira leg.; intertidal zone; DZUP POSC- 23 to DZUP POSC- 25, LIPY UFPB TUN- 395, slides DZUP DID 5.30 to DID 5.31 • 1 colony; same collecting data as for preceding but 6 May 2008; Projeto Biota Paraíba leg.; intertidal zone; LIPY UFPB TUN- 230 • 4 colonies; Baia da Traição, 06°41′15″ S, 34°55′50″ W; 0–0.3 m depth; 12 Mar 2013; L. M. Oliveira leg.; intertidal zone; DZUP POSC- 13 to POSC- 14, slides DZUP DID 5.13 to DID 5.14 • 3 colonies; Quebramar Cabedelo; 06°57′42″ S, 34°50′34″ W; 0–0.5 m depth; 25 Mar. 2013; L. M. Oliveira leg.; intertidal zone; DZUP POSC- 29 to POSC- 31 • 1 colony; Pomar das Esponjas; 07°08′04″ S, 34°46′20″ W; 1–5 m depth; 12 Jan. 2009; Projeto Biota Paraíba leg.; snorkeling; LIPY UFPB TUN- 176 • 2 colonies; Ponta do Cabo Branco; 0 7 o 08′50″ S, 34 o 47′51″ W; 0–0.3 m depth; 28 Mar. 2013; L. M. Oliveira and R. M. Rocha leg.; intertidal zone; DZUP POSC-15 to POSC-16, slides DZUP DID5.15 to DID5.16 • 4 colonies; Praia de Carapibus; 7°16′19″ S, 34°48′07″ W; 0–0.3 m depth; 26 Mar. 2013; L. M. Oliveira and R. M. Rocha leg.; intertidal zone; DZUP POSC-26 to DZUP POSC-28, LIPY UFPB TUN-396 • 5 colonies; Praia de Coqueirinho; 07°16′19″ S, 34°48′07″ W; 0–0.3 m depth; 27 Mar. 2013; L. M. Oliveira and R. M. Rocha leg.; intertidal zone; DZUP POSC-18 to POSC-22 • 3 colonies; same collecting data as for preceding but 3 Jun. 2008; Projeto Biota Paraíba leg.; intertidal zone; LIPY UFPB TUN-153, LIPY UFPB TUN-156. – Pernambuco • 1 colony; Goiana, Pontas de Pedras; 07°37′17″ S, 34°48′15″ W; 13 Dec. 2013, J. Nogueira leg.; intertidal zone; DZUP POSC-045. – Espírito Santo • 2 colonies; Carapebus; 20°13″ 46.02″ S, 40°12′12.67″ W; 0–0.3 m depth; 24 Jan 2012; G.A. Gamba leg.; intertidal zone; DZUP POSC-055, slide DZUP DID5.06 • 3 colonies; Aracruz, Santa Cruz; 20°01′53.12″ S, 40°09′29.22″ W; 0–0.3 m depth; 25 Jan. 2012; G.A. Gamba leg.; intertidal zone; DZUP POSC-056 to POSC-057, DZUP POSC-059, slides DZUP DID5.07 to DID5.08, DZUP DID5.10. GHANA: 7 colonies; Elmira Gold Coast; 11 Oct. 1938; F.R. Irvine and V.G. Foote leg.; NHM 1959.5.27.23, NHM 1959.5.27.24 • 1 colony; Elmira Gold Coast; 28 Dec. 1932, E.D. Plumptre leg.; NHM 1937.1.5.1. PUERTO RICO • 1 colony; 10 Jul 1915; AMNH 797 • 1 colony; 30 Jun 1915; AMNH 798. UNITED STATES – Florida • several colonies; Atlantic side, Biscayne Bay, banks near Soldiers Keys; 3 Mar. 1916; W.G Van Name leg.; AMNH 314 • 2 colonies; Gulf of Mexico, St. Teresa, seagrass beds; 29°53′41.3″ N, 84°33′23.4″ W; 2 m depth; 7 Nov 2011; sand; UF 1127 • 1 colony; Gulf of Mexico, north of St. Petersburg; 29°01′40.8″ N, 83°35′19.3″ W; 18–20 m depth; 12 Mar 2011; G. Paulay, M. Bemis and N. Evans leg.; UF 1037 • 5 colonies; Gulf of Mexico, Hudson; 28°21′05.4″ N, 82°55′04.8″ W; 6 m depth; 2 May 2011; G. Paulay leg.; UF 1749, slide DZUP DID5.09 • 1 colony; Gulf of Mexico, Dry Tortugas, n° 23; 10 Jun. 1931; Tandy-Colman leg.; NHM 1931.12.25.2 • 1 colony; Gulf of Mexico, off Florida; 26°16′49″ N, 82°44′01″ W; 30.4 m depth; 19 Jul. 1981; USNM 17364. Emended description The specimen in NHM 1914.5.18.103 (Bermuda) has not been dissected because of the small size of the colony. It has a gelatinous and transparent tunic, without spicules, through which zooids could be seen on the colony surface without a pattern of organization. The specimen from the Atlantic coast of Florida (AMNH 314) has a brownish colour, is also small (3 cm in diameter and 1 mm thick), with several cloacal apertures and a spicule layer on the colony surface. The zooids are brownish and the atrial languet is bifurcated. The lateral thoracic organ is circular and protruding at the level of the 2 nd row of stigmata. The abdomen has a glandular tissue. The testis has three follicles surrounded by four coils of the sperm duct. Other specimens from the Gulf of Mexico (USNM 17364; Fig. 2; UF 1037, UF 1127 and UF 1749) have an atrial languet with a flat tip rather than bifurcated and testis with four follicles surrounded by five coils of the sperm duct. The glandular tissue in the abdomen has not been observed. Larvae were found in sample UF 1749 only. They look like those found in the specimens from São Paulo, Brazil. The specimens from Puerto Rico (AMNH 797 and AMNH 798) are similar in spicule density and zooid morphology to the samples from the Gulf of Mexico. The colonies from Ghana (NHM 1959.5.27.23-24) are less than 3 cm in diameter. In contrast with the information given about this sample by Millar (1953), the larval trunk is 0.8 mm long. The colonies are pinkish-purple, gelatinous, the colony surface is smooth, shiny and marked with a spicule accumulation around the oral siphons. The zooids are 0.8–1.0 mm long. The oral siphon has six short triangular lobes. The atrial aperture is small. The atrial languet is bifurcated, sometimes with a flat tip. The lateral thoracic organs are circular, not protruding and located in the anterior region of the thorax at the level of the 2 nd row of stigmata, close to the atrial aperture. The pharynx has six stigmata per half row. The abdomen is positioned horizontally in relation to the thorax. The secondary gut loop overlays the stomach. The testis is divided in five follicles surrounded by three coils of the sperm duct. The larvae are present on the colony surface. They are elliptical, gemmiparous, uncoloured, trunk measuring 0.8–1.0 mm. A tail with a diameter of 35 µm winds about halfway around the trunk. Three adhesive papillae are close together. The sucker of the central adhesive papilla is 100 µm in diameter. There are six elongated ectodermal ampullae on each side. The sensorial vesicle lays in the posterior region of the larval trunk. The ocellus is 40 µm long. The distance between ocellus and anterior region of the tail is 200 µm. Larva with two embryos: oozoid dorsal and blastozooid ventral. The morphological characteristics of the zooids of the Brazilian specimens are very similar to those observed by Van Name (1902), although the variation in colony colour and spicule density is much larger in Brazil. The colour varies from purple to brick. The colonies are 3 to10 cm in diameter and 1 to 3 mm thick (Fig. 3). The atrial languet can be bifurcated or with a flat tip. The pharynx has seven to nine stigmata per half row. The lateral thoracic organ is circular and protruding at the level of the 2 nd row of stigmata. The testis has three to five follicles (even in zooids of the same colony), surrounded by three to five coils of the sperm duct. The larva is gemmiparous, with a trunk that is 0.8 to1.0 mm long. A tail 85 to 90 µm wide winds about three-quarters of the way around the trunk. The peduncles of the adhesive papillae are long, while the sucker of the central adhesive papilla is 63 to 80 µm in diameter. There are six or eight pairs of ectodermal ampullae, but four pairs in different stages of duplication were seen in immature larvae (Fig. 4 c–f). The sensorial vesicle is in the mid or posterior dorsal region of the larval trunk. The ocellus is 56 to 60 µm long. The distance between the ocellus and the anterior region of the tail is 185 to 238 µm. The pharynx of the oozooid has 8, 7, 6, 6 stigmata on each half row. Remarks Lotufo (2002) claimed that Brazilian specimensof this species differ from the ones described by Van Name (1902) in the different arrangement of spicules and in the single cloaca per colony. However, the colonies studied by us showed a huge variation in colour, spicule density and cloaca number as also observed by Pérès (1949) and Millar (1953) in African specimens. Lotufo (2002) also mentioned having studied a sample from the type series deposited in the American Museum of Natural History, with very large larvae (1.5 mm trunk length), but we were not able to find and examine this sample in the museum collection. The only sample close to the type locality with available larvae was one from Florida (UF1749), with larvae whose trunk varies from 0.8 mm to 1.2 mm within the same colony. F. Monniot (2016) compared specimens from French Guiana with those from Bermuda and concluded that they belonged to the same species. Molecular analyses (ML and IB) also suggest the existence of only one valid species. Samples from Panama to south Brazil grouped in one clade, corresponding to P. amethysteum with a significant bootstrap value (95%) and posterior probability support (IB = 1) (Fig. 5). Although this clade seems to be split in two branches, one of them does not have enough bootstrap support. The intraspecific genetic divergence (p-distance) among haplotypes ranged from 0.7 to 9.8%, while the interspecific divergence with P. lacazei was ~22%, and with P. poro was ~27%. Based on genetic evidence and the lack of clear morphological separation in the samples examined, we consider that they all belong to P. amethysteum, a species with a large phenotypic variation. The haplotype UPDID096-17 from Rio de Janeiro, in contrast, is a different species with 12.4 to 14.9 % distance from P. amethysteum, and will be commented on later (Polysyncraton sp.). Distribution Type locality: Bermuda (Van Name 1902). Other localities: United States – Florida (Van Name 1945), Puerto Rico, Cuba, Belize (Goodbody 2000; Van Name 1945), Guadeloupe, Martinique (Gravier 1955), Panama (this study), Colombia (Van Name 1945), French Guiana (F. Monniot 2016), Brazil – Ceará to Santa Catarina (Millar 1977; Lotufo 2002; Rocha et al. 2012), Cape Verde, Senegal, Ghana (Pérès 1948; Millar 1953; C. Monniot & F. Monniot 1967)., Published as part of Oliveira, Livia M., Hoeksema, Bert W. & Rocha, Rosana M., 2019, Polysyncraton (Ascidiacea, Didemnidae): a re-examination of some specimens and descriptions of three new species, pp. 1-25 in European Journal of Taxonomy 519 on pages 4-10, DOI: 10.5852/ejt.2019.519, http://zenodo.org/record/2650112, {"references":["Van Name W. G. 1902. The Ascidians of the Bermuda Islands. Transactions of the Connecticut Academy of Arts and Sciences 11: 325 - 412. Available from https: // www. biodiversitylibrary. org / page / 13464308 [accessed 20 Jul. 2018].","Rodrigues S. A. 1962. Algumas ascidias do litoral sul do Brasil. Boletim da Faculdade de Filosofia, Ciencias e Letras, Universidade de Sao Paulo 24: 193 - 216.","Millar R. H. 1977. Ascidians (Tunicata: Ascidiacea) from the northern and north-eastern Brazilian shelf. Journal of Natural History 11: 169 - 223. https: // doi. org / 10.1080 / 00222937700770131","Rocha R. M., Moreno T. R. & Metri R. 2005. Ascidias (Tunicata, Ascidiacea) da Reserva Biologica Marinha do Arvoredo, Santa Catarina, Brasil. Revista Brasileira de Zoologia 22: 461 - 476.","Lotufo T. M. C. & Silva A. M. B. 2006. Ascidiacea do litoral Cearense. In: Matthews-Cascon H. & Lotufo T. M. C. (eds) Biota marinha da Costa Oeste do Ceara: 221 - 247. Serie Biodiversidade 24, Ministerio do Meio Ambiente, Fortaleza, Brazil.","Monniot F. 2016. Ascidians (Tunicata) of the French Guiana Expedition. Zootaxa 4114 (3): 201 - 245. https: // doi. org / 10.11646 / zootaxa. 4114.3.1","Van Name W. G. 1921. Ascidians of the West Indian region and south eastern United States. Bulletin of the American Museum of Natural History 44: 283 - 494.","Moure J. S., Bjornberg T. K. S & Loureiro T. S. 1954. Protochordata ocorrentes na entrada da Baia de Paranagua. Dusenia 5: 233 - 242.","Millar R. H. 1958. Some ascidians from Brazil. Annals and Magazine of Natural History 1: 497 - 514. https: // doi. org / 10.1080 / 00222935808650975","Millar R. H. 1953. On a collection of ascidians from the Gold Coast. Proceedings of the Zoological Society of London 123 (2): 277 - 325. https: // doi. org / 10.1111 / j. 1096 - 3642.1953. tb 00176. x","Lotufo T. M. C. 2002. Ascidiacea (Chordata: Tunicata) do litoral tropical brasileiro. PhD Thesis. Instituto de Biociencias da Universidade de Sao Paulo, Brazil.","Peres J. M. 1949. Contribution a l'etude des ascidies de la cote occidentale d'Afrique. Bulletin de l'Institut francais d'Afrique noire 11 (1 - 2): 159 - 207.","Van Name W. G. 1945. The North and South American ascidians. Bulletin of the American Museum of Natural History 84: 1 - 476.","Goodbody I. 2000. Diversity and distribution of ascidians (Tunicata) in the Pelican Cays, Belize. Atoll Research Bulletin 480: 303 - 333. Available from https: // repository. si. edu / handle / 10088 / 5860 [accessed 20 Mar. 2019].","Gravier R. 1955. Ascidies recoltees par le \" President Theodore Tissier \" (Campagne de Printemps 1951). Revue des Travaux de l'Institut des Peches maritimes 19: 611 - 631.","Rocha R. M., Zanata T. B. & Moreno T. R. 2012. Keys for the identification of families and genera of Atlantic shallow water ascidians. Biota Neotropica 12: 269 - 303. https: // doi. org / 10.1590 / S 1676 - 06032012000100022","Peres J. M. 1948. Note sur deux especes d'ascidies du Gulf de Marseille. Bulletin du Musee d'Histoire naturelle de Marseille 8 (2 - 3): 54 - 61.","Monniot C. & Monniot F. 1967. Tuniciers benthiques. Annales de l'Institut oceanographique 2: 1 - 18."]}

Polysyncraton trivolutum (Millar, 1960) References: Didemnum trivolutum Millar 1960: 58 –60, fig. 12 A–B. Polysyncraton trivolutum Monniot & Monniot 1983: 43 –46, fig. 8 A–H, pl. IV A–D (synonymy); Monniot & Monniot 1994: 18; Tatián et al. 2005: 209; Monniot et al. 2011: 10, fig. 3. Material examined: several colonies adhered to the tunic of Ascidia meridionalis; trawl; -37.9876 lat. -54.6906 long. (station 8); 854 m; 11 August 2012 —three colonies adhered to corals; trawl; -37.9530 lat. -55.1843 long. (station 2); 291 m; 10 August 2012 —one colony on one fragment of coral; trawl; -37.9651 lat. -54.5320 long. (station 10); 1144 m; 11 August 2012 (Figures 8 A–D). Colonies configure flat and encrusting white patches on the tunics of A. meridionalis, debris and corals (Fig. 8A). The most superficial layer shows the greatest amount of spicules, which are specially concentrated around the oral apertures (Fig. 8B). Distributed unevenly and attached to the substrate, numerous yellow and spherical eggs (approximately 0.9 mm in diameter) were found (Fig. 8C). The zooids show an average length of 1.8 mm. Thorax and abdomen have the same size. The atrial languet is short and triangular. There is no muscular appendage. The thorax is separated from the abdomen by a thin and short neck. The stomach is rounded, almost spherical, and smooth-walled. The gonads, both male and female, are situated inside the intestinal loop. The number of male follicles ranges from three to four. They are densely packed in pear-shaped lobes. The vas deferens makes three to four spiral turns around them (Fig. 8D). In some zooids only the ovary is developed. Remarks. On the revision of the colonies described by Millar (1960) as Didemnum trivolutum from the Argentine Sea (Malvinas / Falkland Islands and Patagonian shelf), Monniot & Monniot (1983) concluded that these specimens corresponded to the genus Polysyncraton based on: (1) the presence of one pointed atrial languet and (2) the morphology of the testes. Polysyncraton trivulutum is an eurybathic species, widely distributed in Antarctic and Sub-Antarctic waters up to the Patagonian shelf (Argentine Sea). The present is the northernmost record of the species. It is also the first record of the species below 935 m (Kott 1969)., Published as part of Maggioni, Tamara, Taverna, Anabela, Reyna, Paola B., Alurralde, Gastón, Rimondino, Clara & Tatián, Marcos, 2018, Deep-sea ascidians (Chordata, Tunicata) from the SW Atlantic: species richness with descriptions of two new species, pp. 1-28 in Zootaxa 4526 (1) on pages 14-15, DOI: 10.11646/zootaxa.4526.1.1, http://zenodo.org/record/2611359, {"references":["Millar, R. H. (1960) Ascidiacea. Discovery Reports, 30, 1 - 160.","Monniot, C. & Monniot, F. (1983) Ascidies antarctiques et subantarctiques: Morphologie et Biogeographie. Memoires du Museum National d'Histoire Naturelle, Paris, 125, 1 - 168.","Monniot, C. & Monniot, F. (1994) Ascidians collected in the Weddell Sea by the RV ' Polarstern' (EPOS cruise leg 3). Bulletin du Museum National d'Histoire Naturelle, Paris, 16, 13 - 37.","Tatian, M., Antacli, J. C. & Sahade, R. (2005) Ascidians (Tunicata, Ascidiacea): species distribution along the Scotia Arc. Scientia Marina, 69 (2), 205 - 214. https: // doi. org / 10.3989 / scimar. 2005.69 s 2205","Monniot, F., Dettai, A., Eleaume, M., Cruaud, C. & Ameziane N. (2011) Antarctic Ascidians (Tunicata) of the French- Australian survey CEAMARC in Terre Adelie. Zootaxa, 2817, 1 - 54.","Kott, P. (1969) Antarctic Ascidiacea. Antarctic Research Series, 13, 1 - 239."]}

Polysyncraton trivolutum (Millar, 1960) Fig. 3 C,D,G References and synonymy: Polysyncraton trivolutum Millar (1960) p. 58; Monniot & Monniot (1983) p. 43; Monniot et al. (2011) p. 10. Localities: 5 S. This species forms crusts several cm across and 4���5 mm thick. The colour is white with a brownish tinge. The spicules are dense, in general less than 25 ��m in diameter (occasionally reaching 40). They are stellate with short rays, up to ten in optical section. The general cavity of the colony is at the thoracic level, but it extends between groups of abdomina. The thoraces reach 2 mm in length. They have an atrial languet that ranges from very small and simple to long and with several points. Cup-like thoracic organs are prominent between the second and third row of stigmata. No retractor muscle is present. The abdomina are smaller than the thoraces, and are in general in male phase. They have three testicular lobes surrounded by a sperm duct describing four coils. Some zooids also have a few developing oocytes adjacent to the testes. Remarks. the presence of atrial languet, absence of retractor muscle, structure of thoracic organs and gonads allows the assignment of our specimens to this species. However, P. trivolutum is highly variable and may comprise a group of closely related species (Monniot & Monniot 1983). This taxon is common in Antarctic and subantarctic regions (Monniot & Monniot 1983, Monniot et al. 2011, Schories et al. 2015)., Published as part of Turon, Xavier, Ca��ete, Juan I., Sellanes, Javier, Rocha, Rosana M. & L��pez-Legentil, Susanna, 2016, Ascidian fauna (Tunicata, Ascidiacea) of subantarctic and temperate regions of Chile, pp. 151-180 in Zootaxa 4093 (2) on page 158, DOI: 10.11646/zootaxa.4093.2.1, http://zenodo.org/record/267667

Polysyncraton amethysteum Van Name, 1902 Figure 4 D. Stations. SC 9; SC 12; SC 13; SS 2; SS 3; SS 4; SS 12; SR 8; SR 10; SR 11; SR 14; SR 21; SR 23; SR 25; SB 3. Common on all kinds of substrates the colonies in large or small thin crusts are variable in a colour, always purple but more or less dark. The spicule density varies and they are sometimes absent or restricted to the colony surface. The Guiana material has been compared to specimens from Bermuda in the MNHN collection and all characters are similar. The thorax has a large atrial languet and a muscular thoracic appendage. The testis is divided into 4 lobes, rarely less, circled by the sperm duct in 4 to 5 turns. The larva 0.85mm in length (Fig. 4 D) has 3 adhesive papillae, 8 pairs of ampullae and one lateral bud. The spicules are variable in size: the largest do not exceed 50 ��m and are made of balls of needles. P. amethysteum is present on both sides of the Atlantic Ocean and recorded as well in the Caribbean and along the Brazilian coast (Monniot F. 1984; Rocha, Moreno & Metri 2005)., Published as part of Monniot, Fran��oise, 2016, Ascidians (Tunicata) of the French Guiana Expedition, pp. 201-245 in Zootaxa 4114 (3) on pages 207-208, DOI: 10.11646/zootaxa.4114.3.1, http://zenodo.org/record/257053, {"references":["Van Name, W. G. (1902) The ascidians of the Bermuda Islands. Transactions of the Connecticut academy of Arts and Sciences, XI, 325 - 412.","Monniot, F. (1984) Ascidies littorales de Guadeloupe VII. Questions de systematique evolutive posees par les Didemnidae. Bulletin du Museum national d'Histoire naturelle Paris, 6 A (4), 885 - 905.","Rocha, R. M., Moreno, T. R. & Metri, R. (2005) Ascidias (Tunicata, Ascidiacea) da Reserva Biologica Marinha do Arvoredo, Santa Catarina, Brasil. Revista Brasileira de Zoologia, 22 (2), 461 - 476. http: // dx. doi. org / 10.1590 / S 0101 - 81752005000200024"]}

Ascidian spicules are reported for the first time from the upper Eocene (Paleogene) biosiliceous marls and mudstones of the Blanche Point Formation in the St. Vincent Basin, southeastern Australia. The spicules that belong to the family Polycitoridae are identified as a Recent speciesCystodytescf.dellechiajei, andCystodytessp. and spicules of the family Didemnidae are indentified as representing generaLissoclinum, Didemnum, andPolysyncraton.Five other different morphological spicule types which can be classified only at the family level also belong to the Didemnidae. This study demonstrates that ascidians had a very wide distribution by the late Eocene and that ascidian fauna was already of a modern character.

Three new species of Enterocola are described: E. dicaudatus n. sp., from the ascidian host Polysyncraton rostrum Monniot & Monniot collected in Tanzania, E. monnioti n. sp., from the ascidian host Polyclinum constellatum Savigny collected in Bahrain, and E. parapterophorus n. sp., from the ascidian host Didemnum granulatum Tokioka taken in Djibouti. In all three species, the mandibles are interpreted as being represented by a pair of setulose seta-like elements that are largely concealed beneath similar paired setulose structures, the labral palps, carried on the labrum. The paired elements interpreted as mandibles are transversely orientated and lie in a groove, the anterior margin of which forms a defined ridge ornamented with spinules.

Bioassay-guided fractionation of the crude CH2Cl2/MeOH extract from the Australian ascidian Polysyncraton echinatum led to the isolation of a new pyridoacridine alkaloid, 12-deoxyascididemin (1), along with two known analogues, ascididemin (2) and eilatin (3). The structure of 1 was determined following extensive analysis of 1D/2D NMR and MS data. Biological evaluation showed that compounds 1–3 are potent antitrypanosomal agents with IC50 values of 0.077, 0.032, and 1.33 μM against Trypanosoma brucei brucei, respectively.

Among the 13 species of didemnid ascidians collected during several expeditions in the NW Pacific, 8 are species of the genus Didemnum. Only D. papillatum Romanov and D. pseudobiglans Romanov from Commander Islands and D. vermiforme Romanov from the Sea of Japan were represented by many specimens. Most other species of the family were represented in the present material only by a few specimens. Two new species of Didemnum are described from the Alaska Gulf, 79 to 195m. One of these, as well as some colonies of Polysyncraton crassum Redikorzev, are devoid of spicules.

Polysyncraton pseudomagnetae sp. nov. (figure 17E) Distribution. Type locality: Northern Territory (Darwin, Angler Reef, 10���12 m, coll. B. Glasby and party, 31 August 2002, holotype QM G308612). Description. The colony is a hard sheet mottled white and grey. Spicules are in the surface sometimes, especially over the common cloacal canals, mixed with black pigment particles. Also, there are aggregations of black pigment in the base of the colony. Zooids are along each side of the common cloacal canals that surround white zooid-free areas. White spicules are crowded throughout the colony and can be seen through the open common cloacal apertures, which expose the base of common cloacal cavity. In some parts of the colony the common cloacal canals expand into horizontal spaces, penetrating in amongst the thoraces, isolating them from one another, each with a ventral strip of test. Spicules are to 0.06 mm diameter and are of two types, some with pointed and others with flat-tipped rays. Spicules have 15���17 rays in optical transverse section. Zooids have a long thorax with eight stigmata in the anterior row, a short retractor muscle from the top of the oesophageal neck, a short, bifid atrial tongue and five coils of the vas deferens around four or five testis follicles. Remarks. This species has the same range of spicules as P. magnetae Hastings, 1931 and similar systems. However, the spicules are larger, the retractor muscle projects from the top of the oesophageal neck rather than from some way down it, and the present species has more coils of the vas deferens, P. magnetae having only three coils. Polysyncraton longitubis from South Australia has similar but smaller spicules with fewer rays and more coils of the vas deferens; and P. millepore Vasseur, 1968 has slightly smaller spicules, also with fewer rays. Polysyncraton pseudorugosum Monniot, 1993 (figure 17F) Polysyncraton pseudorugosum Monniot, 1993: 10; Kott, 2001: 123; 2002c: 33. Distribution. Previously recorded (see Kott, 2001, 2002c): Queensland (Hervey Bay); Northern Territory (Darwin, Bathurst I.); Coral Sea. New records: Northern Territory (Darwin, Angler Reef, QM G308598, Stevens Rock, QM G308600). Description. Both newly recorded colonies are flat lamellae, orange in life, with rounded margins produced out into short, rounded to cylindrical lobes. The colonies are hard and greenish yellow in preservative and the preservative is the same colour. Firm pillars of solid test extend through the depth of the colony, and are surrounded by circular common cloacal canals lined on each side by zooids, the ventral surfaces of the thoraces embedded in the pillars of solid test and the abdomina bent around into the layer of spicule-free test that lines the base of the common cloacal canals. The surface of the colony is depressed over the common cloacal canals. Spicules are large, to 0.09 mm diameter, stellate, with 9���11 conical, pointed rays and they are present throughout the colony except for the thin aspiculate layer of test lining the common cloacal canals. Zooids have a wide atrial aperture exposing most of the branchial sac directly to the common cloacal cavity and reducing the parietal body wall to a narrow strip along each side of the endostyle. Seven stigmata are in the anterior row. The vas deferens coils four times. Larvae are present in the basal test. The trunk is deep, 0.7 mm long with up to 12 lateral ampullae on each side of the antero-median adhesive organs. There is at least one blastozooid. Remarks. The newly recorded colonies of this well-characterized species are as previously described. The common cloacal canals, and the thin layer of aspiculate test lining them occur also in Polysyncraton peristroma, but the species have different spicules and are a different colour. The spicules resemble those of P. cuculliferum but are larger and they do not become sparser toward the base of the colony as they do in P. cuculliferum. The spicules that most closely resemble those of the present species are those of P. montanum, which is distinguished from the present species principally by the upright conical colony, as opposed to the hard, flattened lamellae of the present species., Published as part of Kott, Patricia, 2010, New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (part 2), pp. 2455-2526 in Journal of Natural History 38 (26) on pages 2483-2484, DOI: 10.1080/00222930701359218, {"references":["MONNIOT, F., 1993, Ascidies de Nouvelle-Caledonie XIII. Le genre Polysyncraton (Didemnidae), Bulletin Museum National d'Histoire Naturelle, Paris, serie 4, 15 A (1 - 4), 3 - 17."]}

Polysyncraton textus sp. nov. (figure 18C) Distribution. Type locality: Western Australia (8.5 n. mls NW of Port Hedland, 18 m, coll. J. Fromont on RV Soela, 5 August 1982, holotype WAM 556.88). Description. The colony is an extensive white sheet overgrowing worm tubes. It is white in preservative. Stellate branchial apertures with a margin of spicules are arranged around small intensely white unperforated areas of the surface. Deep primary common cloacal canals extend the full length of the zooids and surround circles of zooids with their ventral surfaces embedded in ligaments of test between the surface and base of the colony. Small spicule-filled papillae are crowded on the surface between the branchial apertures. An even layer of relatively crowded spicules is in the surface test and another less crowded layer is on the base of the colony. Spicules are sparse elsewhere. The spicules are small, stellate, to 0.037 mm diameter, with 15���17 relatively short and irregular, sometimes subdivided conical rays in optical transverse section. The ray length/spicule diameter ratio is about 0.2. Zooids have a tulip-shaped branchial siphon and a large bifid atrial tongue. The branchial sac is large, but the stigmata could not be counted. Three coils of the vas deferens surround four or five testis follicles, the outside coil encircling the base of a large egg. Larvae being incubated in the basal test have a trunk 0.85 mm long with the tail wound about three-quarters of the way around it. A corona of about 16 round-tipped lateral ampullae surround the three anteromedian ampullae at the anterior end of the trunk. The larval pharynx does not appear to be perforated, although the gut is differentiated and the otolith and ocellus are present. Blastozooids were not detected. Remarks. Relatively few species in this genus have stellate spicules similar to the present ones. Polysyncraton arafurensis Tokioka, 1952 and P. multiforme Kott, 2001 do have similar spicules although they are larger than those of the present species and are crowded throughout the colony. Other characters, such as the large bifid atrial tongue, the large larvae with relatively rudimentary larval organs but large number of lateral ampullae and the loose and relatively few coils of the vas deferens are characteristic of many Polysyncraton spp. Didemnum albopunctatum Sluiter, 1909 (figure 18D) Didemnum albopunctatum Sluiter, 1909: 58; Kott, 2001: 148 and synonymy; 2004. Distribution. Previously recorded (see Kott, 2001, 2004): Western Australia (Rowley Shoals), Queensland (Capricorn Group, Swain Reefs, Whitsunday Is), Indonesia, New Caledonia, Palau Is, Fiji. New record: Northern Territory (Dudley Bommies, QM G308627). Description. The newly recorded colony is soft and flexible, possibly due to the small spicules and the deep common cloacal cavity. They are whitish black in life with white rims around the common cloacal apertures. In preservative the colony is brownish grey on the surface, with white points where the spicule-filled lobes of the evenly spaced, stellate branchial apertures open to the surface. Linings of the branchial apertures are black owing to the pigment in the superficial layer of test that turns in to line the siphons. The pigment in the superficial layer of test is mixed with the small spicules and overlies a non-pigmented layer of test. Zooids cross the deep horizontal common cloacal cavities singly or in clumps with dark pigment and sparse spicules mixed in the test connectives that surround them. The abdomina especially are encapsulated in black pigment cells in the test. Common cloacal cavities do not penetrate the test posterior to the zooids, and the basal test is opaque and white with crowded spicules. Spicules are small (to 0.035 mm diameter) and globular with numerous flat-tipped, rod-like rays. Zooids have eight stigmata in the anterior row and six in the posterior row and a large open atrial aperture without an anterior lip. Remarks. This specimen has the usual small globular spicules and the black pigment of formerly described specimens, although the black squamous epithelium of the Swain Reefs specimen (see Kott, 2001) has not been detected. Didemnum candidum Savigny, 1816 (figure 18E) Didemnum candidum Savigny, 1816: 194; Kott, 2001: 157 and synonymy. Distribution. Previously recorded (see Kott, 2001): Queensland (Low Is), Western Pacific, West Indian Ocean (Tanzania, Mauritius, Malagasy), Gulf of Suez, Gulf of Arabia. New record: Western Australia (Houtman���s Abrolhos, WAM 557.88). Description. The newly recorded colony is about 5 mm thick with rounded margins and is smooth on the upper surface. The surface layer of test is thin. The common cloacal cavity is a horizontal space with thoraces crossing it in their own ventral strip of test. Abdomina are embedded in the relatively thick basal layer of test. A single sessile common cloacal aperture is on the surface. Spicules are crowded throughout the colony. They are relatively uniform with five to seven, and occasionally nine short, rod-like rays in optical transverse section. Zooids have a small thorax with a sessile atrial aperture without an atrial lip and a relatively large abdomen containing a long, curved gut loop. A long, tapering retractor muscle projects from about halfway down the oesophageal neck. The undivided testis is surrounded by seven coils of the vas deferens. Remarks. The specimen is as previously described for this species and the spicules are the usual stellate form with relatively few, short rod-like rays, differing from those previously described only in the maximum spicule size (0.07 mm diameter), which is more than previously reported for this species. Although previously known from the western Indian Ocean, the Arabian Gulf and its type locality in the Red Sea, this is the first record from the eastern Indian Ocean., Published as part of Kott, Patricia, 2010, New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (part 2), pp. 2455-2526 in Journal of Natural History 38 (26) on pages 2487-2489, DOI: 10.1080/00222930701359218, {"references":["TOKIOKA, T., 1952, Ascidians collected by Messrs Renzi Wada and Seizi Wada from the Pearl Oyster bed in the Arafura Sea in 1940, Publications of the Seto Marine Biological Laboratory, 2, 91 - 142.","SLUITER, C. P., 1909, Die Tunicaten der Siboga Expedition Pt. 2. Die merosomen Ascidien, Siboga Expeditie, 56 B, 1 - 112.","SAVIGNY, J. C., 1816, Memoires sur les Animaux sans Vertebres, Part 2 (Paris: G. Dufour), 239 pp."]}

Polysyncraton montanum sp. nov. (figures 5B, 17C) Distribution. Type locality: South Australia (Kangaroo I., Pissy Boy Rock between Snug Cove and Western River Cave on rock wall, 8���10 m, coll. K. Gowlett Holmes, holotype SAM E3224). Description. In life the colony looks like a Leptoclinides, being a deep, slightly asymmetrical, mottled pink and white cone with a large terminal common cloacal aperture. The preserved colony is pinkish orange and the label is stained the same colour. The colony is smooth on the surface. Internally, bright orange zooids line the deep primary common cloacal canals surrounding test connectives to which the zooids are firmly attached, appearing to be in tight clumps. A thin superficial bladder cell layer is aspiculate but beneath that the spicules are crowded throughout. They are stellate, up to 0.08 mm diameter, with 9���11 conical pointed rays in optical transverse section. Zooids have large thoraces with a broad flat-tipped atrial lip. A long tapering retractor muscle projects from the oesophageal neck. Gonads were not detected in the newly recorded specimens, and the number of stigmata could not be counted. Remarks. The tropical P. pseudorugosum Monniot, 1993 (see Kott, 2001 and below) is not readily distinguished from the present species, having similar systems and spicules. However, it has a sheet-like colony with many common cloacal apertures rather than terminal ones like the present species. Other species of Polysyncraton with similar common cloacal systems and stellate spicules with 9���11 pointed conical rays are P. cuculliferum with smaller spicules (to 0.06 mm diameter) and P. sideris Kott, 2001 (with larger spicules to 0.14 mm diameter). The broad atrial lip resembles that of P. tegetum, but the spicule rays are never chisel-shaped. The colony is a similar colour to colonies of Didemnum fragum Kott, 2001 and has a similar terminal common cloacal aperture, but D. fragum has smaller zooids, lacks an atrial lip and has shorter spicule rays. The present species appears to be previously undescribed. Polysyncraton pedunculatum Kott, 2001 Polysyncraton pedunculatum Kott, 2001: 121 (part, not specimen QM GH2387, Flinders I., pl. 6D~ P. rica) and synonymy; 2004. Distribution. Previously recorded (see Kott, 2001, 2004): South Australia (Great Australian Bight, Nuyts Archipelago, Yorke Peninsular, Investigator Strait). New record: South Australia (Kangaroo I., SAM E3230). Description. The living colony is reddish tan, slightly translucent, biramous vertically ridged with a short, relatively narrow, basal stalk. Zooids are confined to the surface of the completely aspiculate colony. They are in irregular longish oval groups with primary common cloacal canals around each group. The test is soft and translucent. Zooids have the usual long, fine retractor muscle projecting from about halfway down the oesophageal neck. Three coils of the vas deferens surround a number of testis follicles. Remarks. Kott (2001) confused specimens of P. rica (which is only partially aspiculate with a smooth surface) with the present completely aspiculate, irregularly ridged species, which looks very different. The report of four coils of the vas deferens (Kott, 2001) is incorrect. Reexamination of the material has shown that there are three coils in all specimens., Published as part of Kott, Patricia, 2010, New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (part 2), pp. 2455-2526 in Journal of Natural History 38 (26) on pages 2481-2482, DOI: 10.1080/00222930701359218, {"references":["MONNIOT, F., 1993, Ascidies de Nouvelle-Caledonie XIII. Le genre Polysyncraton (Didemnidae), Bulletin Museum National d'Histoire Naturelle, Paris, serie 4, 15 A (1 - 4), 3 - 17."]}

A novel pyridoacridine alkaloid 12-deoxyascididemin (I) is isolated together with the known ascididemin (II) and eilatin and their biological evaluation shows potent antitrypanosomal activity.

Polysyncraton horridum n. sp. (Figs 25; 26; 75A) HOLOTYPE. ��� Palau. Toachel Mid, Koror-Babeldaob Channel, 7��19.24���N, 134��31.28���E, 7-20 m, 29.XI.2001, coll. P. L. Colin, 0CDN6281-M (MNHN A2 POL 105). PARATYPE. ��� Palau. Toachel Mid, Koror-Babeldaob channel, 7��20.114���N, 134��31.03���E, 6-33m, coll. P. L. Colin, 0CDN6281-M (MNHN A2 POL 104). AUTRE MAT��RIEL EXAMIN��. ��� Palau. Toachel Mid, Koror- Babeldaob Channel, 7��21.03���N, 134��30.90���E, 15 m, 3.VI.1994, coll. CRRF, 0CDN2398-P (MNHN A2 POL 103). ��TYMOLOGIE. ��� Du latin horridus: h��riss��. DESCRIPTION Les colonies (Fig.75A)r��colt��es en diverses stations ont toutes le m��me aspect.��paisses de 2 �� 3 mm, elles sont souples, de couleur brun vert plus ou moins fonc��, le liquide fixateur prend une couleur noire.La surface est r��guli��rement sur��lev��e en d��mes au sommet desquels s���ouvrent les orifices cloacaux communs bord��s de 5 �� 7 papilles digitiformes remplies de spicules. La surface de la colonie est lisse mais appara��t frip��e par contraction. La forme g��n��rale des colonies d��pend du support qu���elles encro��tent. Souvent repli��es sur elles-m��mes, les colonies contiennent alors des d��bris divers et du s��diment. La surface des colonies devient plus ou moins verd��tre par la pr��sence de Prochloron en surface. Les colonies se composent de 2 couches. La couche sup��rieure qui contient d���abondantes cellules pigmentaires brunes, des spicules ��toil��s et les thorax des zo��des. Elle est s��par��e de la couche basale, qui contient les abdomens et les larves, par de vastes canaux cloacaux. Les spicules sont abondants dans toute l�����paisseur de la tunique. Les zo��des ont un thorax large (Fig. 25A). Le siphon buccal est bord�� de 6 lobes filiformes, il est court et large. L���ouverture cloacale est tr��s grande et porte ant��rieurement une languette bifide plus ou moins grande selon l���emplacement du zo��de (Fig. 25A, D). Les organes thoraciques lat��raux se situent au niveau du premier sinus branchial, ou au deuxi��me rang de stigmates au bord du manteau. La branchie compte en moyenne 12 stigmates de chaque c��t�� dans les 3 premiers rangs, 9 �� 10 stigmates dans le 4 e rang. Le manteau est color�� en brun. La taille est courte et porte un appendice fixateur plus court que la longueur du thorax. L���abdomen (Fig. 25B, C) est color�� en brun. La boucle intestinale est plane avec un estomac volumineux. Le testicule est constitu�� de 4 ou 5 lobes tr��s serr��s. Le spermiducte d��crit 2 ou 3 tours l��ches. L���ovaire est situ�� contre le testicule avec un seul ovocyte �� la fois en maturation. Les embryons se d��veloppent au contact de l���abdomen et sont color��s en brun. Les larves (Fig.25E) ne sont pr��sentes que dans les colonies r��colt��es en novembre et sont dans un ��tat juv��nile. Le tronc mesure 750 ��m. Aucun d��but de diff��renciation en organes n���est visible. Les 3 papilles adh��sives sont courtes et ��paisses dans un sillon ant��rieur, mais il n���y a pas trace de v��sicules ��pidermiques. La queue d��crit un tour autour du tronc. Les spicules en ast��risques sont de tailles tr��s diverses en surface comme en profondeur dans la colonie, le diam��tre le plus fr��quent est 85 ��m, mais il atteint souvent 100 ��m; les rayons sont assez peu nombreux mais tr��s longs et pointus (Fig. 26). REMARQUES Par la forme de la colonie en syst��mes jointifs avec chacun leur ouverture cloacale commune, par la couleur, la languette cloacale, le grand nombre de stigmates, plusieurs lobes testiculaires mais peu de tours du spermiducte, cette esp��ce se rapproche beaucoup de P. glaucum Kott, 2001 dont l���holotype QM G305628 a ��t�� examin��. Polysyncraton glaucum diff��re par des spicules �� rayons moins longs et moins pointus, de 55 ��m selon nos mesures et la figure de Kott (2001 fig. 163G; mesure diff��rente de celle indiqu��e dans le texte), et par des syst��mes polygonaux dans la colonie beaucoup plus nettement d��limit��s.Le nombre de stigmates dans la branchie est moins grand que dans la nouvelle esp��ce.Les organes thoraciques lat��raux sont situ��s plus post��rieurement. Les colonies de P. glaucum sont beaucoup plus rigides. Les orifices cloacaux communs ne portent pas de longues papilles pleines de spicules et les lobes buccaux ne sont pas filiformes., Published as part of Monniot, Fran��oise & Monniot, Claude, 2008, Compl��ments sur la diversit�� des ascidies (Ascidiacea, Tunicata) de l'ouest Pacifique tropical, pp. 799-872 in Zoosystema 30 (4) on pages 816-817, DOI: 10.5281/zenodo.4690007, {"references":["KOTT P. 2001. - Th e Australian Ascidiacea. Part 4, Aplousobranchia (3), Didemnidae. Memoirs of the Queensland Museum 47 (1): 1 - 407."]}

Key to Polysyncraton 1 Systems separate, circular or polygonal each with central common cloacal aperture; spicules always stellate.................. 2 – Systems not separate; spicules not always stellate.......... 4 2 Separate systems in elevated lobes; spicules to 0.07 mm with 7–9 rays in optical transverse section............ P. galaxum Kott, 2004b – Separate systems not in elevated lobes; spicules with more than 9 rays in optical transverse section.................... 3 3 Spicules to 0.1 mm diameter with 13–15 rays in optical transverse section.................... P. pavimentum Monniot, 1993 – Spicules to 0.08 mm diameter with 9–11 rays in optical transverse section....................... P. polysystema sp. nov. 4 Spicules all less than 0.05 mm................ 5 – Spicules not all less than 0.05 mm diameter........... 10 5 Spicules only in a layer at surface and sometimes on base....... 6 – Spicules throughout colony................ 8 6 Spicules with 9–11 rays in optical transverse section.. P. alingulum Kott, 2004c – Spicules with more than 11 rays in optical transverse section....... 7 7 Spicules with 17–19 rays in optical transverse section; four coils of the vas deferens.............. P. miniastrum Kott, 2004a – Spicules with 15–17 rays in optical transverse section; three coils of the vas deferens................ P. textus Kott, 2004b 8 Spicules stellate with long, thick rays....... P. catillum Kott, 2004b – Spicules with short conical, rounded, or truncated rays (sometimes globular).. 9 9 Spicule rays 9–11 in optical transverse section; colonies black; 10 coils of the vas deferens............... P. longitubis Kott, 2004b – Spicules rays 11–13 in optical transverse section; colonies not black; 8 coils of the vas deferens............... P. luteum Kott, 2004a 10 Spicules burr-like or globular................ 11 – Spicules stellate.................... 12 11 Spicules burr-like, present throughout colony.... P. reticulum Kott, 2004b – Spicules globular in thin plate at surface....... P. nivum Kott, 2004c 12 Spicules only in surface test................ 13 – Spicules throughout colony................ 16 13 Spicule rays long and spiky.......... P. turris Kott, 2004a – Spicule rays not long and spiky............... 14 14 Spicule rays 11–17 in optical transverse section.... P. arvum Kott, 2004c – Spicule rays 9–11 in optical transverse section........... 15 15 Spicule rays rounded............ P. linere Kott, 2004a – Spicule rays conical and pointed........ P. montanum Kott, 2004b 16 Spicule rays 7–9 in optical transverse section........... 17 – Spicule rays 15–17 in optical transverse section. P. pseudomagnetae Kott, 2004b 17 Spicules to 0.1 mm diameter......... P. rostrum Kott, 2004b – Spicules to 0.06 mm diameter......... P. peristroma Kott, 2004b, Published as part of Kott, Patricia, 2005, New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (Part 3), pp. 2409-2479 in Journal of Natural History 39 (26) on pages 2415-2416, DOI: 10.1080/00222930500087077, http://zenodo.org/record/5215680, {"references":["Kott P. 2004 b. New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (part 2). Journal of Natural History 38 (19): 2455 - 2526.","Monniot F. 1993. Ascidies de Nouvelle-Caledonie XIII. Le genre Polysyncraton (Didemnidae). Bulletin du Museum National d'Histoire Naturelle, Paris, Serie 4 15 A (1 - 4): 3 - 17.","Kott P. 2004 c. Ascidiacea (Tunicata) from Australian waters of the Timor and Arafura Seas. The Beagle, Records of the Museums and Art Galleries of the Northern Territory 20: 37 - 81.","Kott P. 2004 a. New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (part 1). Journal of Natural History 38 (6): 731 - 774."]}

Polysyncraton miniastrum sp. nov. (figure 6B, C) Distribution. Type locality: Queensland (Shelburne Bay, 22 m, encrusting worm tube, coll. AIMS Bioactivity Group, 11 April 1994, holotype QM G308537). Description. The colony is a smooth-surfaced encrusting sheet. Spicules are in a thin layer in the surface and the base, but are only patchy or sparse between. Those in the surface layer are interrupted by evenly spaced stellate branchial apertures and minute spherical vesicles are arranged in a circle around each branchial aperture. Spicules are small (to 0.036 mm diameter) with 17–19 relatively short conical rays in optical transverse section. The common cloacal cavity is thoracic. The colony is said to have been orange in life. Contracted zooids in the holotype have large thoraces with short cylindrical branchial siphons and large sessile atrial apertures with a pronounced tongue from the anterior rim of the opening. The number of stigmata could not be accurately determined but there appear to be more than 10 per row in the wide thorax. A retractor muscle was not detected, but may be present. The gut loop is long and the testis, against the dorsal side of the distal end of the loop, has four or five testis follicles and is surrounded by four well-separated coils of the vas deferens. Larvae are not known. Remarks. The only other Polysyncraton known to have similar small spicules is Polysyncraton magnetae Hastings, 1931 which, however, has a diversity of spicule shapes, some stellate with long pointed rays and others almost globular with rounded or flat-tipped rod-like rays. Further, P. magnetae has a thin superficial layer of bladder cells, its spicules are crowded throughout and its zooids are arranged along each side of circular canals. Polysyncraton circulum Kott, 1962 is a tropical species with similar vesicles surrounding each branchial aperture and spicules missing from the centre of the colony. However, spicules are larger with more rays and some are globular and sometimes hollow., Published as part of Kott, Patricia, 2004, New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (part I), pp. 731-774 in Journal of Natural History 38 (19) on page 743, DOI: 10.1080/00222930310001647334, http://zenodo.org/record/4653689, {"references":["HASTINGS, A. B., 1931, Tunicata, Scientific Reports of the Great Barrier Reef Expedition 1928 - 1929, 4 (3), 69 - 109.","KOTT, P., 1962, The ascidians of Australia III. Aplousobranchiata Lahille: Didemnidae Giard, Australian Journal of Marine and Freshwater Research, 13 (3), 265 - 334."]}

Polysyncraton linere sp. nov. (figure 4) Distribution. Type locality: Victoria (Western Port, 23 m, 25 November 1974, holotype MV F70228). Description. The thin encrusting colony has spicules crowded in the surface test and in the floor of the horizontal thoracic common cloacal cavity, but are not present in the translucent basal test beneath the common cloacal cavity. Spicules are to 0.07 mm diameter and have 9–11 short rounded projections (rather than conical rays) in optical transverse section. These projections are not crowded, and are evenly spaced on a large spherical central mass. Zooids have a short branchial siphon with six pointed lobes around the aperture. The rim of the atrial aperture flares out, but lacks an atrial lip. Eight stigmata are in the anterior row of the branchial sac. Five coils of the vas deferens surround about five male follicles. A retractor muscle was not detected. The larval trunk, 0.5 mm long, has the tail wound three-quarters of the way around it and six pairs of lateral ampullae. Blastozooids were not detected. Remarks. Polysyncraton victoriensis Kott, 1976 and Didemnum turritum: Kott, 1976, known only from Western Port, are distinguished from the present species by their deep primary common cloacal canals, forked atrial tongue, smaller spicules to 0.04 mm diameter (Kott, 1976: 0.4 m sic) with about seven conical pointed rays in optical transverse section crowded throughout. Polysyncraton lithostrotum (Brewin, 1956) from New Zealand has similar spicules, but its isolated common cloacal systems distinguish it., Published as part of Kott, Patricia, 2004, New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (part I), pp. 731-774 in Journal of Natural History 38 (19) on pages 738-739, DOI: 10.1080/00222930310001647334, http://zenodo.org/record/4653689, {"references":["KOTT, P., 1976, Ascidian fauna of Western Port Bay, Victoria and a comparison with that of Port Phillip Bay, Memoirs of the National Museum of Victoria, 37, 53 - 96.","BREWIN, B. I., 1956, Ascidians from the Chatham Is and the Chatham Rise, Transactions and Proceedings of the Royal Society of New Zealand, 84 (1), 121 - 137."]}

Polysyncraton magnetae Hastings, 1931 Polysyncraton magnetae Hastings, 1931: 100; Kott, 2001: 109 and synonymy. Distribution. New record: Queensland (Little Broadhurst Reef, QM GH5346). Previously recorded (see Kott, 2001): Queensland (northern and southern Great Barrier Reef). Description. The newly recorded specimen is a small, hard scrap, probably of a thin sheet-like colony. It is said to have been white in life. Zooids are along each side of deep circular common cloacal canals that surround opaque, slightly elevated stands of spicule-filled test. The branchial apertures are inconspicuous, not being lined with spicules. Spicules are especially crowded in the upper half of the colony and in a layer on the base. Eggs are yellow, but zooids are white in preservative. Spicules to 0.035 mm diameter are a mixture of globular ones with flat-tipped, rodlike rays and stellate ones with sharp conical round-tipped to conical rays, zooids are robust with a thick, short to moderate-length retractor muscle from threequarters of the way down a muscular oesophageal neck. Nine rather fusiform stigmata are in the anterior row. A circle of 10, well-separated, long, clavate testis follicles, each narrowing to a relatively long vas efferens, is surrounded by three loose coils of the vas deferens in the long sac-shaped abdomen. Remarks. The species has the characteristic common cloacal system (reflected in the quilted appearance of the colony surface caused by depressions over the primary common cloacal canals). Also characteristic are the form and size of the spicules, robust zooids with a muscular oesophageal neck, and the loose cluster (Kott, 2001: 110, 'grape-like') of testis follicles in the long sac-like abdomen. The species has been recorded on only three previous occasions, once from Low Isles and twice from Heron Island. The new record is from the central section of the Great Barrier Reef., Published as part of Kott, Patricia, 2004, New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (part I), pp. 731-774 in Journal of Natural History 38 (19) on page 741, DOI: 10.1080/00222930310001647334, http://zenodo.org/record/4653689, {"references":["HASTINGS, A. B., 1931, Tunicata, Scientific Reports of the Great Barrier Reef Expedition 1928 - 1929, 4 (3), 69 - 109.","KOTT, P., 2001, The Australian Ascidiacea Pt 4, Aplousobranchia (3) Didemnidae, Memoirs of the Queensland Museum, 47 (1), 1 - 407."]}

Polysyncraton pedunculatum Kott, 2001 (figure 7A) Polysyncraton pedunculatum Kott, 2001: 121 and synonymy. Distribution. New records: South Australia (Top Gallant I, QM GH962; Ward I., QM GH928; Franklin I., QM GH2290). Previously recorded (see Kott, 2001): South Australia. Description. Newly recorded colonies are firm, slightly flattened, inverted cones, narrowing to short, thick, fleshy stalks, or spherical or mushroom-shaped heads with the stalk from the centre of the under surface. Although Kott (2001) refers to an extensive posterior common cloacal cavity separating the zooid layer from the central test, this cavity occurs only in a specimen from the Yorke Peninsular (QM G302867). Zooids are along each side of thoracic primary common cloacal canals that form a network with the surface depressed slightly over these canals. There are no posterior abdominal cavities. Colonies are reported to have been dark blue or purple in life. Zooids are long, as previously described, with a short narrow atrial lip, long narrow thorax, retractor muscle from halfway down a long oesophageal neck, and four loose coils of the vas deferens around six or seven loose testis follicles. Larvae are in the central test of specimens collected in March (QM GH962). The large (0.8 mm long), robust trunk has the tail wound three-quarters of the way around it. Conspicuous striations are on the surface of the test. A spherical yolk mass is in the anterior part of the trunk behind six broad ectodermal ampullae on each side of the three antero-median adhesive organs. A waist separates the ampullae from the mass of the larval trunk in more advanced larvae but is not conspicuous. A thoracic blastozooid is at the base of the oozooid gut loop on the left. An external horizontal ampulla was not detected. Remarks. The colonies resemble those of Polysyncraton rica, although that species has sessile colonies (without a stalk), spicules in a layer beneath the surface, a fine retractor muscle from the top of the oesophageal neck, only three coils of the vas deferens, sometimes a particularly large atrial tongue, a posterior abdominal cavity always separating the central test from the zooid layer and zooids in clumps rather than along each side of common cloacal canals. The larva of the present species previously was not known. Although it is the same length as that of P. rica and has a single blastozooid, it differs in its six (rather than eight) long, narrow lateral ampullae on each side of the antero-median adhesive organs, a less pronounced waist, striations on the larval test and it lacks a conspicuous horizontal ampulla on the left side of the trunk. The appearance of living colonies of this species is not known, photographs of colonies of P. rica having been wrongly assigned to it (Kott, 1997: pl. 85; Kott, 2001: pl. 6D; see below, P. rica)., Published as part of Kott, Patricia, 2004, New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (part I), pp. 731-774 in Journal of Natural History 38 (19) on pages 743-745, DOI: 10.1080/00222930310001647334, http://zenodo.org/record/4653689, {"references":["KOTT, P., 2001, The Australian Ascidiacea Pt 4, Aplousobranchia (3) Didemnidae, Memoirs of the Queensland Museum, 47 (1), 1 - 407.","KOTT, P., 1997, Tunicata, in S. Shepherd and M. Davies (eds) Marine Invertebrates of Southern Australia (Adelaide: South Australian Research and Development, Aquatic Sciences with the Flora and Fauna of South Australia Handbooks Committee), pp. 1107 - 1280."]}

Polysyncraton turris sp. nov. (figure 8 A–C) Distribution. Type locality: Queensland (Shelburne Bay, 43 m, coll. AIMS Bioactivity Group, 22 March 1994, holotype QM G308538). Description. The rather gelatinous colony is sheet-like and encrusting. A thin superficial layer of bladder cells overlies a relatively sparse layer of spicules at zooid level. Beneath the zooids, the basal test is translucent and spicule-free. The cloacal cavity is thoracic but limited and inconspicuous. Spicules are stellate, to 0.07 mm diameter with 13–15 long, spiky, pointed rays, occasionally truncated (or broken off?) at the tip or near the base of the ray. The ray length / spicule diameter ratio is about 0.35 or more. A group of two or three spicules is in the branchial siphon lining. The colony is said to have been light pink in life. Zooids are about 1.5 mm long, a long branchial siphon is about one-third of the length of the rest of the thorax and has six shallow lobes around the aperture. The large atrial aperture exposes most of the branchial sac, and has a forked atrial tongue from its anterior margin. An oval lateral organ is opposite the first interspace between the rows of stigmata. A fine retractor muscle projects from the top of the relatively long oesophageal neck. About nine stigmata are in the anterior row, reducing to six in the posterior row. The gut forms a relatively short loop with gonads against its dorsal side. In some zooids, four coils of the vas deferens surround four or five testis follicles. In others, the testis appears to be degenerate and spermfilled coils of the vas deferens (acting as a seminal vesicle) lie against a large egg in the abdomen. Larvae are not known. Remarks. Zooids of the known specimens of Polysyncraton arafurensis Tokioka, 1952 are similar to the present species, spicules are similar (with 13–15 pointed rays) and type localities are not far removed from one another. However, the spicule rays of the present species are longer and more attenuated than those of P. arafurensis and the rather gelatinous colony with its spicule-free base and superficial bladder cell layer also differs from the hard spicule-filled colonies of P. arafurensis. The present species also lacks the marginal spicules outlining the stellate branchial apertures on the surface of P. arafurensis colonies. Polysyncraton millepore Vasseur, 1969 has similar attenuated spicule rays to the present species but they are fewer and colonies are thin, hard and packed with spicules throughout. The attenuated spicule rays and gelatinous colony with spicules missing from the surface and the basal half of the colony are characteristic of this species., Published as part of Kott, Patricia, 2004, New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (part I), pp. 731-774 in Journal of Natural History 38 (19) on pages 746-747, DOI: 10.1080/00222930310001647334, http://zenodo.org/record/4653689, {"references":["VASSEUR, P., 1969, Deuxieme contribution a l'etude des ascidies de Madagascar region de Tulear, Bulletin du Museum national d'Histoire naturelle, Paris, 40 (5), 912 - 933."]}

Polysyncraton adelon n. sp. (Figs 54B; 56) TYPE MATERIAL. — Palau. Southwest Islands, Sonsoral, 5°20.88’N, 132°13.80’E, 15 m, 24.VII.1995 (MNHN A2 POL 94). ETYMOLOGY. — From the Greek adelon: hardly visible. DESCRIPTION Grey-green in formalin, the colonies form very soft, extensive sheets 1 to 2 mm thick. They are easily delaminated, as the common cloacal cavities are extensive at the thoracic level. The spicules are dense everywhere and mixed with dark pigment cells, which are more abundant in the upper layer and around the thoraces. The common cloacal cavity does not penetrate the abdominal layer of the colony. The zooids are greenish in formalin. The oral siphon is short with very small lobes. The cloacal opening is very wide, without a languet, uncovering a large part of the branchial sac (Fig. 56A). There are eight or nine stigmata in the first and second half rows, seven in the posterior row. The lateral thoracic organ is round, placed above the third transverse vessel or the fourth stigmata row (Fig. 56A). The retractor muscle is of variable length, but not longer than the thorax, and arises mid-way down the oesophageal peduncle. The abdomen (Fig. 56B) is slightly smaller than the thorax. The gut loop is wide open, with a spherical anterior stomach. The gonads are included in the digestive loop. There are three or more often four testis lobes, pressed into a rosette and covered by four to five turns of the sperm duct (Fig. 56B). The ovary (Fig. 56C) replaces the testis in the zooid’s reproductive cycle. No larvae were present in the colonies studied. The spicules reach 35 µm in diameter. They are spheres made of multiple thin blunt rays, not pointed ones (Fig. 54B). REMARKS This species is placed in the genus Polysyncraton instead of Didemnum according to the pragmatic understanding detailed earlier (Monniot F. 1993), as it has no cloacal languet but four testis lobes. Rather few species in this genus exist with many testis lobes but no cloacal languet. By its colour when preserved, the present species looks like P. hartmeyeri Michaelsen, 1923 from the Red Sea, which has five testis lobes, five to six turns of the sperm duct, more stigmata in a row, and – the most telling distinction – no retractor muscle. P. magnetae Hastings, 1931 from the Great Barrier Reef has five testes but only two coils of the sperm duct, and its zooids are distributed in double rows. Polysyncraton victoriensis Kott, 1976 from southern Australia has three to four testis follicles, but the spicule shape and arrangement is different and there are only six stigmata per half row. She does not mention a cloacal languet in her description. P. tubiporae Michaelsen, 1920 from Zanzibar has a spicule-free layer at the colony surface, lateral thoracic organs placed anteriorly, and six to eight testes encircled by two to three loose turns of the sperm duct. Polysyncraton aspiculatum Tokioka, 1949 (Fig. 121A) Didemnum (Polysyncraton) aspiculatum Tokioka, 1949: 2, pl. 2, fig. 1-3. Type locality: Japan. Synonymy: see Monniot C. et al. in press, South Africa. MATERIAL EXAMINED. — Philippines. Luzon, NE side of Maricaban Island, Gamao Point, 13°38.39’N, 120°56.86’E, 16 m, 25.VII.1994 (MNHN A2 POL 81). DESCRIPTION The colonies are thick light brown crusts (Fig. 121A) with a network of depressed lines above the cloacal channels. The cloacal apertures are not numerous. The colony surface is smooth and clean. Spicules are totally absent. The tunic is filled with vesicular cells and round, brown pigment cells. The structure of the zooids is the same as in specimens from other regions and in the type specimen. The cloacal languet is large with two long lobes in zooids near the common cloacal apertures. The branchial sac has eight stigmata per row on each side and is as brown as the remaider of the body. The testis follicles are numerous, about eight in a rosette encircled by two and a half coils of the sperm duct. The larvae are large compared to the zooid size. They have three adhesive papillae and eight pairs of ampullae grouped in pairs. The body wall has vesicular cells as figured by Tokioka (1953) for this species. REMARKS The distribution of P. aspiculatum in the western Indian Ocean, southern Australia, the Philippines, and Japan is particularly wide. The variability in density of spicules and pigment cells in different locations raises questions about the presence of just a single species, but the zooids and larvae are identical., Published as part of Monniot, Françoise & Monniot, Claude, 2001, Ascidians from the tropical western Pacific, pp. 201-383 in Zoosystema 23 (2) on pages 272-273, DOI: 10.5281/zenodo.5391440, {"references":["HASTINGS A. B. 1931. - Tunicata. Scientific Report of the Great Barrier Reef Expedition 1928 - 29 4 (3): 69 - 109.","KOTT P. 1976. - The ascidian fauna of Western Port, Victoria, and a comparison with that of Port Phillip Bay. Memoirs of the National Museum, Victoria 37: 53 - 96.","MICHAELSEN W. 1920. - Die Krikobranchien Ascidien des Westlichen Indischen Ozeans: Didemniden. Mittelungen aus dem Zoologischen Museum Hamburg 37: 1 - 74.","TOKIOKA T. 1949. - Contributions to Japanese ascidian fauna. I: Ascidians collected by Prof. Miyachi and Mr Masui during the bottom survey 1939 - 40. Publications of the Seto Marine Biological Laboratory 1 (1): 1 - 17.","TOKIOKA T. 1953. - Ascidians of Sagami Bay. Iwanami Shoten, Tokyo, 313 p."]}

Polysyncraton cerebellum n. sp. (Figs 57; 58A; 121B) TYPE MATERIAL. — Palau. Southwest Islands, Helen Reef, overhang, 2°53.03’N, 131°44.94’E, 12 m, 10.XII.1996 (MNHN A2 POL 97). ETYMOLOGY. — From the Latin cerebellum: brain. OTHER MATERIAL EXAMINED. — Papua New Guinea. Louisiade Archipelago, Calvados Island Chain, Brooker Channel, 11°03.09’S, 152°28.62’E, 12 m, 1.VI.1998 (MNHN A2 POL 96). DESCRIPTION In large crusts about 2-3 mm thick, these colonies are marbled with brown on a white ground. The pattern suggests a brain’s surface (Fig. 121B) (hence the species name). The zooids are irregularly placed on the sides of large channels delimiting oval or polygonal areas. The common cloacal apertures are numerous and stellate. The pigment cells are superficial. Dark brown inclusions lie in the basal test. The colonies are easily delaminated into a surface layer containing the oral siphons and the cloacal languets and a basal layer containing the abdomens and larvae. The thoraces are included in pillars of tunic uniting these layers. The oral siphons are large, funnel-shaped, with six lobes (Fig. 57A, B). The cloacal aperture uncovers most of the branchial sac. The languet is either short with a round tip (Fig. 57A) or, in zooids near the common cloacal apertures, large and T-shaped (Fig. 57B). The branchial sac has eight to 10 stigmata per side in the first row. The lateral thoracic organs protrude from the rim of the cloacal aperture at the level of the first or second stigmata row. The retractor muscle, shorter than the thorax, projects at the base of the oesophageal peduncle (Fig. 57A). The gut loop is largely opened and only slightly twisted when the testis is fully mature. There are two testis follicles, tightly pressed against each other, covered by five turns of the sperm duct (Fig. 57C). The ovary develops against the testis with one large oocyte. The larval trunks are 1 mm long. Larvae have three adhesive papillae and at their base a comb-like crown of 24 pairs of ampullae. The spicules (Fig. 58A) are stellate with numerous short, pointed rays. The largest spicules reach 65 µm in diameter. They are very dense throughout the tunic, making it stiff. REMARKS This species is very similar to P. thallomorpha Monniot F., 1993. It differs in the colony’s pigment pattern and the arrangement of the zooids in meshes. Also, the oral siphon is less wide in this new species. The lateral thoracic organs are above the third row of stigmata in P. thallomorpha. The larvae are very similar in both species. The spicules have more rays in P. cerebellum n. sp. Polysyncraton lithostrotum Brewin, 1956 from New Zealand and recorded again in New Caledonia (Monniot F. 1993: 4, fig. 1, pl. 1A) has also a mosaic pattern but a very different one; the zooids in that species are included in polygons in the centre of each of which opens a single common cloacal cavity. The anatomy of the zooids and larvae in that species are exactly the same as in P. cerebellum n. sp. Polysyncraton thallomorpha Monniot F., 1993 (Fig. 121C) Polysyncraton thallomorpha Monniot F., 1993: 13, fig. 7, pl. IIA. Type locality: New Caledonia. MATERIAL EXAMINED. — Philippines. Bohol Sea, Camiguin Island, 9°12.89’N, 124°38.03’E, 7 m, 18.IV.1997 (MNHN A2 POL 88). DESCRIPTION The colonies have the characteristic shape described in New Caledonia; hard, thin crusts partially raised above the sediment. The colour is darker here, almost black, but the margins of the lobes remain white (Fig. 121C). The undersurface of the leaf-like crust is extremely hard with ridges. The pigment cells are dendritic, restricted to the colony’s upper surface. The zooids have the characteristic long and wide oral siphon, and a large cloacal aperture with a languet varying in length according to the proximity of the zooids to the common cloacal cavity. The lateral thoracic organs protrude at the level of the third stigmata row. The two testis lobes overlap the gut loop and are covered by five turns of the sperm duct. The larvae have three adhesive papillae encircled by very numerous digitiform ampullae. The spicules are irregular, as figured in Monniot F. (1993: pl. II A)., Published as part of Monniot, Françoise & Monniot, Claude, 2001, Ascidians from the tropical western Pacific, pp. 201-383 in Zoosystema 23 (2) on pages 273-275, DOI: 10.5281/zenodo.5391440

Polysyncraton vestiens n. sp. (Figs 58B; 59) TYPE MATERIAL. — Palau. Koror, Lighthouse Reef Basin, 7°17.90’N, 134°28.34’E, 47 m, 20.VII.1998 (MNHN A2 POL 95). ETYMOLOGY. — From the Latin vestiens: clothing. DESCRIPTION The thin colonies are encrusting, 1 mm thick. They are very soft, semitransparent, and colourless in formalin preservative. The resistant tunic is only present in a superficial and basal layer and around the zooids, which are isolated in small groups in bridges uniting the surface to the base of the colony. The spicules are not dense and allow one to see the zooids through the tunic. There is no special accumulation of spicules around the oral siphons. The six oral lobes are low around the rim of a narrow siphon. The cloacal aperture uncovers most of the branchial sac (Fig. 59A). The dorsal languet is very variable, sometimes short and round but sometimes very large and T-shaped (Fig. 59A). The lateral thoracic organs, extremely small (or absent), lie at the level of the second transverse sinus or the second stigmata row. There is no retractor muscle. There are 10 to 12 stigmata in the first half row. The oesophageal peduncle is long and the abdomen, smaller than the thorax (Fig. 59A), is folded under the thorax. The abdomen has the usual components of the genus. The gonads lie in the gut loop. The testis is made of three to six lobes in a protruding rosette (Fig. 59A). The well-developed sperm duct is coiled in three turns above the centre of the testis rosette. The ovary matures after the testis. Numerous larvae are present in the basal layer of the colony after the gonads have regressed. The trunk is 0.7 mm in length, the tail makes three quarter of a turn around it. There are three wellseparated adhesive papillae on long stems and eight pairs of finger-like ampullae, resulting from the division of the four original pairs (Fig. 59B). There is one bud on each side of the larval visceral mass (Fig. 59B). The very small spicules (Fig. 58B) are stellate, with numerous short rays: their diameter is 30 µm. REMARKS This species is closely allied to Polysycraton purou Monniot C. & Monniot F., 1987 from Polynesia and closely resembles it in its appearance and the structure of the larvae. It differs from P. purou in smaller spicules that are also present around the zooids, a wider cloacal aperture, and the absence of a retractor muscle., Published as part of Monniot, Françoise & Monniot, Claude, 2001, Ascidians from the tropical western Pacific, pp. 201-383 in Zoosystema 23 (2) on pages 275-276, DOI: 10.5281/zenodo.5391440

An antitumor antibiotic, namenamicin, purified from the marine ascidian Polysyncraton lithostrotum is disclosed. An antitumor composition for treating cancerous tumors comprises namenamicin and an inert carrier. A method of treating an individual for cancer comprises administering the composition comprising namenamicin and an inert carrier. A method of purifying namenamicin, a method of inhibiting the growth of a microorganism, and a method of cleaving DNA at a sequence-specific site are also described.

[Based on specimens collected in the western Mediterranean, a redescription is provided of Brementia balneolensis Chatton & Brement, notodelphyid copepod parasitic in the ascidian Polysyncraton canetensis Brement. In the same host lives another species of Notodelphyidae new to science, whose general morphology is similar to that of B. balneolensis, from which it differs definitely by numerous characteristics. Our present knowledge of the phylogeny of ophioseidimorph Notodelphyidae refrained the authors to establish a new genus for this new species, described under the name of Brementia illgi. A discussion on phylogenetic trends in the genus Brementia and its relationships with other Notodelphyidae, together with some remarks on the host specificity of both species of Brementia conclude the paper., Based on specimens collected in the western Mediterranean, a redescription is provided of Brementia balneolensis Chatton & Brement, notodelphyid copepod parasitic in the ascidian Polysyncraton canetensis Brement. In the same host lives another species of Notodelphyidae new to science, whose general morphology is similar to that of B. balneolensis, from which it differs definitely by numerous characteristics. Our present knowledge of the phylogeny of ophioseidimorph Notodelphyidae refrained the authors to establish a new genus for this new species, described under the name of Brementia illgi. A discussion on phylogenetic trends in the genus Brementia and its relationships with other Notodelphyidae, together with some remarks on the host specificity of both species of Brementia conclude the paper.]

Polysyncraton lacazei is a colonial tunicate (family didemnidae) living in the NW-mediterranean rocky sublitoral. A thorough scanning of numerous colonies revealed that in spite of an apparently heavy local fouling pressure only one fouling species — a kamptozoan — is encountered with some regularity on Polysyncraton. We try to define the epibiotic situation of sessile marine organisms as composed of four epibiotic parameters: longevity or exposure time (A), epibiont load (E), colonizer pool (CP) and fouling-period (FP). Subsequently, these factors are combined to propose an “Antifouling Potential” index: AFP=(1−E/CP)×A/(FP+A). This index is intended to permit evaluating the relative antifouling defense potency to be expected in a given organism in a given epibiotic situation and to compare different cases of epibiosis and fouling.