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A colonial ascidian of the genus Distaplia caused a mass mortality of the pen shell Atrina maura (Sowerby, 1835) during June 2016 in the southwest of the Gulf of California (Mexico), with a significant socio-economic cost. Tentatively identified in previous works as Distaplia cf. stylifera, a precise taxonomic determination was still lacking. In the present work, based on a detailed morphological study, it is confirmed that this aggressive species is Distaplia stylifera (Kowalevsky, 1874). Originally described from the Red Sea, the species currently has a wide circumtropical distribution (with the exception of the Eastern Pacific to date) and is reported as introduced in parts of its range. The present account thus represents an important range extension of this species. However, when revising the original description and later observations, the reported variability of several characters makes it likely that the binomen is in fact a complex of species, as is common in other ascidians with wide distributions. A complete morphological and genetic study including populations from the entire range of distribution would be necessary to settle the status of D. stylifera. Taxonomic uncertainties hinder a correct interpretation of biogeographical patterns and inference on the origin of the studied population. Nevertheless, the known introduction potential of the species, coupled with an explosive growth in an anthropized environment, and the lack of any previous reports in the Eastern Pacific, strongly suggest that the investigated population represents yet another instance of ascidian introduction. From the point of view of management, its invasive behavior is cause for great concern and warrants mitigation measures.

Deep-sea benthic communities from the Weddell Sea, Antarctica, were sampled in January–April 2005 in an area located between 61°S–70°S and 0°W–49°W. We found a total of eight ascidian species that belong to five different families, of which one corresponded to a new species. These were: Protoholozoa pedunculata Kott, 1969; Corynascidia suhmi Herdman, 1882; Styela andeepensis Maggioni & Tatián sp. nov.; Culeolus suhmi Herman, 1881; Culeolus anonymus Monniot F. & Monniot C., 1976; Culeolus likae Sanamyan K. & Sanamyan N., 2002; Oligotrema lyra (Monniot C. & Monniot F., 1973) and Asajirus indicus (Oka, 1913). We report: the extension of the known distribution ranges of P. pedunculata, Corynascidia suhmi, Culeolus suhmi, C. likae and A. indicus, being the first time they are collected from the Weddell Sea; and the shallowest record of C. likae. Six species were added to the list of ascidians of the Weddell Sea, being all deep-sea representatives. While the total number of ascidian species augmented from 43 to 49, the number of deep-sea representatives increased from 23 to 29. Our findings, thus, reinforce the need of performing more deep-sea prospections in the area.

Protoholozoa incrustans sp. nov. Figures 4, 5 Station: Kanadeep 12-743-04. Two colonies (Syntypes MNHN A3. PRO 8 – slides A3. 1494-1498). Both colonies form soft transparent crusts on sponges or didemnids. The largest colony (Fig. 4) is 3 cm in extent and 1.5 mm in thickness. The glassy tunic contains sparse sand. The zooids do not show a particular design in their arrangement and their oral apertures could not be seen at the surface of the contracted colonies. The zooids are not perpendicular to the colony surface, the oral apertures being superficial but the atrial siphon is located deeper inside the colony thickness nevertheless no common atrial cavities obviously appear in the soft tunic. The thorax reaches 2.2 mm in maximum length and is followed without constriction by the abdomen 0.6 mm long (Fig. 5A–C). The oral siphon is short with 6 pointed lobes. The atrial siphon in posterior position is enlarged in an ampulla narrowed at its extremity with a dented rim (Fig. 5A, C). The body wall is thin and transparent; no muscles are present on the thorax except two long transverse fibres on each side at the base of the thorax which extend from the endostyle along the sides of the atrial siphon. Four to six short oral tentacles are present just below the oral rim. A prepharyngeal band encircles the base of the siphon. The pharynx contains 3 thick transverse branchial bars on each side attached ventrally to a long endostyle and which are dorsally linked to triangular rapheal papillae. The abdomen in continuity with the thorax contains a closed digestive loop. In less contracted zooids the stomach seems square-shaped with 4 low longitudinal crests. The hermaphrodite gonad forms a round mass inside and partly protruding out of the gut loop. No postabdominal process was detected. A single tadpole is often present inside the dilated atrial siphon (Fig. 5A, C). The larval body is 0.55 mm in diameter surrounded by a tail with one and a half turn (Fig. 5D, E). Three well spaced adhesive papillae are placed in a line between an arc of round vesicles on each side. An otolith is present. According to the larval structure and its mode of incubation this new species belongs to the genus Protoholozoa Kott, 1969 as redefined in Monniot & Tatian (2020). Protoholozoa incrustans sp. nov. has common characters with Protoholozoa pigra Monniot F., 1974 collected from the Açores at 1000 m depth which possesses a flat encrusting colony and 3 transverse branchial bands. Protoholozoa incrustans differs from the Atlantic species by the thoracic musculature and the shape of the long inflated atrial siphon in which larvae are incubated. The larva of P. pigra and its incubation mode are unknown. Protoholozoa pedunculata Kott 1969 has a cone-like colony on a peduncle; its larva is incubated in the thorax and has 3 adhesive papillae in a line., Published as part of Monniot, Francoise, 2021, New records of deep-sea ascidians (Tunicata, Ascidiacea) from the New Caledonia region, pp. 443-468 in Zootaxa 4996 (3) on pages 447-448, DOI: 10.11646/zootaxa.4996.3.2, http://zenodo.org/record/5074595, {"references":["Kott, P. (1969) Antarctic Ascidiacea. Antarctic Research Series, 13, 1 - 239.","Monniot, F. & Tatian, M. (2020) Questions on the taxonomic status of species of Protoholozoa Kott, 1969 (Ascidiacea, Aplousobranchia, Holozoidae) with a description of a new genus. Zootaxa, 4718 (2), 261 - 268. https: // doi. org / 10.11646 / zootaxa. 4718.2.7."]}

Scotiazoa lilium (Monniot & Monniot, 1982) Figure 6 Stations: Kanadeep CP 5095; CP 5109. Nine specimens. Protoholozoa lilium Monniot C. & Monniot F. 1982. All colonies are brittle, very soft with a triangular head above a long cylindrical peduncle (Fig. 6A). The diameter of the head (always damaged) is about 1cm, the longest peduncle is 6 cm with 2 mm in diameter. The zooids have their thorax and abdomen contained in the transparent tunic of the head the post abdominal vascular extensions extend into the peduncle. The thorax is in vertical position for most of the zooids with the atrial aperture at the top surface of the colony and the oral siphon near the peduncle. The thoraces are narrow 6 to 8 mm long (Fig. 6C). The body wall is thin with circular muscles at the base of the oral siphon and with 15 transverse muscles along the thorax. There are eight to ten oral tentacles. The branchial tissue includes three transverse bars on each side attached to the endostyle and a dorsal membrane. This organisation corresponds to that of specimens from New Caledonia described as Protoholozoa lilium by Monniot & Monniot (1991, Fig. 15). The digestive loop encircles the hermaphrodite gonad. The ovary is anterior to the testis vesicles which are arranged in a rosette. A pedunculate brood pouch (Fig. 6C) is inserted at the base of the thorax and occasionally contains a single larva. The tadpole has three adhesive papillae in a triangle and one otolith (Fig. 6B). The larval body is 1.7 mm long encircled by the tail. The structure of the larva is typical of the Holozoidae family. It confirms the attribution of the species to the genus Scotiazoa instead of Protoholozoa (see Monniot & Tatian 2020)., Published as part of Monniot, Francoise, 2021, New records of deep-sea ascidians (Tunicata, Ascidiacea) from the New Caledonia region, pp. 443-468 in Zootaxa 4996 (3) on page 449, DOI: 10.11646/zootaxa.4996.3.2, http://zenodo.org/record/5074595, {"references":["Monniot, C. & Monniot, F. (1982) Some Antarctic deep-sea tunicates in the Smithsonian collections. In: Biology of the Antarctic seas. 10. Antarctic Research Series, 32, pp. 95 - 130. https: // doi. org / 10.1029 / AR 032 p 0095","Monniot, C. & Monniot, F. (1991) Tunicata: peuplements d'ascidies profondes en Nouvelle Caledonie. Diversite des strategies adaptatives. Memoires du Museum National d'Histoire Naturelle Paris, A, 151, 357 - 448.","Monniot, F. & Tatian, M. (2020) Questions on the taxonomic status of species of Protoholozoa Kott, 1969 (Ascidiacea, Aplousobranchia, Holozoidae) with a description of a new genus. Zootaxa, 4718 (2), 261 - 268. https: // doi. org / 10.11646 / zootaxa. 4718.2.7."]}

During the 2013 Singapore Strait International Marine Biodiversity Workshop, hundreds of ascidians were collected along with numerous other marine phyla. Collections were made intertidally as well as subtidally by snorkel, SCUBA, trawling and dredging. While many ascidian specimens remain unidentified, 14 aplousobranchs, nine phlebobranchs and 17 stolidobranchs have been identified; a surprising 50% of these comprise 20 new records for Singapore. An additional new record of the phlebobranch Perophora namei collected from the same area in 2014 and 2015 is included here. Of the 21 new records, Aplidium cf. grisiatum, Distaplia regina, Euherdmania cf. digitata, Cnemidocarpa irene, Monandrocarpa monotestis and Polyandrocarpa rollandi are also first records for the entire South China Sea region.

Distaplia micropnoa (Sluiter, 1909) NEW RECORD Figure 3A Colonies mushroom shaped, stalk white with red and yellow cap, color retained in buffered formalin. Zooids arranged in double longitudinal rows on the cap, cloacal openings only at top of colony. Large atrial languet paddle shaped. Stomach with longitudinal folds. #4629, single colony 2 cm total height, 1.1 cm in width; #4649, small colony 1.1 cm across. Distribution: Indonesia, Palau, Australia. References with detailed descriptions and figures: Tokioka (1967), Monniot F. & Monniot C. (2001), Kott (2002a)., Published as part of Lambert, Gretchen, Lee, Serina Siew-Chen & Teo, Serena Lay-Ming, 2021, Ascidians collected during the 2013 Singapore Strait International Marine Biodiversity Workshop, pp. 1-38 in Zootaxa 4933 (1) on page 8, DOI: 10.11646/zootaxa.4933.1.1, http://zenodo.org/record/4547842, {"references":["Sluiter, C. P. (1909) Die Tunicaten der Siboga-Expedition. Part 2. Die merosomen Ascidien. Siboga-Expedition, 56, 1 - 112.","Tokioka, T. (1967) Pacific Tunicata of the United States National Museum. Bulletin of the United States National Museum, 251, 1 - 247. https: // doi. org / 10.5479 / si. 03629236.251.1","Kott, P. (2002 a) Ascidiacea (Tunicata) from Darwin, Northern Territory, Australia. The Beagle, Records of the Museums and Art Galleries of the Northern Territory, 18, 19 - 55."]}

Distaplia regina Kott, 1990 NEW RECORD Figure 3B, C #3850A, a single large flat colony was the only specimen collected, 8 cm across in largest width, growing on an algal blade; tunic in life brownish purple fading to pale pink in formalin, as mentioned by Kott (1990). Zooids in systems more or less circular. The four rows of stigmata lack parastigmatic vessels. Zooid thorax with longitudinal muscles only. Stomach smooth, but under high magnification is very minutely areolated. Largest larva almost 2 mm long, with four tiny rows of stigmata (Fig. 3C), larva appears to have four adhesive papillae similar to one figured (but not commented on) by Monniot F. & Monniot C. (2001). In a slightly younger larva, only the typical three papillae are present, in a triangle. Distribution: Australia, Palau. References with detailed descriptions of the zooids: Kott (1990), Monniot F. & Monniot C. (1996, 2001)., Published as part of Lambert, Gretchen, Lee, Serina Siew-Chen & Teo, Serena Lay-Ming, 2021, Ascidians collected during the 2013 Singapore Strait International Marine Biodiversity Workshop, pp. 1-38 in Zootaxa 4933 (1) on page 8, DOI: 10.11646/zootaxa.4933.1.1, http://zenodo.org/record/4547842, {"references":["Kott, P (1990) The Australian Ascidiacea part 2, Aplousobranchia (1) and Supplement: Phlebobranchia and Stolidobranchia. Memoirs of the Queensland Museum, 29, 1 - 266."]}

Scotiazoa gen. nov. Type species: Protoholozoa lilium Monniot et Monniot, 1982 . Etymology: about the Antarctic research vessel “Scotia”, Scotish National Antarctic Expedition, SNAE. Currently we include two former Protoholozoa species to this genus: P. lilium and P. cantarella. The characters which separate Scotiazoa gen. nov. from Protoholozoa are fertilization/incubation mode and arrangement of the adhesive papillae. In Scotiazoa, larvae are incubated in a brood pouch and adhesive papillae are disposed in a triangle. In Protoholozoa, larvae are incubated in the atrial cavity and adhesive papillae are disposed in a line. Waiting for further information on fertilization, modes of budding and disposition of adhesive papillae, we are maintaining P. australiensis, P. anthos and P. pigra. In addition, we keep all species in Holozoidae until there is a better definition of the family’s diagnostic characters. Additional well-fixed material is necessary for genetic investigations to specify the molecular relatedness of the different species.

Scotiazoa gen. nov. Type species: Protoholozoa lilium Monniot et Monniot, 1982 . Etymology: about the Antarctic research vessel ���Scotia���, Scotish National Antarctic Expedition, SNAE. Currently we include two former Protoholozoa species to this genus: P. lilium and P. cantarella. The characters which separate Scotiazoa gen. nov. from Protoholozoa are fertilization/incubation mode and arrangement of the adhesive papillae. In Scotiazoa, larvae are incubated in a brood pouch and adhesive papillae are disposed in a triangle. In Protoholozoa, larvae are incubated in the atrial cavity and adhesive papillae are disposed in a line. Waiting for further information on fertilization, modes of budding and disposition of adhesive papillae, we are maintaining P. australiensis, P. anthos and P. pigra. In addition, we keep all species in Holozoidae until there is a better definition of the family���s diagnostic characters. Additional well-fixed material is necessary for genetic investigations to specify the molecular relatedness of the different species., Published as part of Monniot, Fran��oise & Tati��n, Marcos, 2020, Questions on the taxonomic status of species of Protoholozoa Kott 1969 (Ascidiacea Aplousobranchia, Holozoidae) with a description of a new genus, pp. 261-268 in Zootaxa 4718 (2) on page 267, DOI: 10.11646/zootaxa.4718.2.7, http://zenodo.org/record/3602396, {"references":["Monniot, C. & Monniot, F. (1982) Some antarctic deep-sea tunicates in the Smithsonian collections. In Biology of the Antarctic seas X. Antarctic Research Series, 32, 95 - 130. https: // doi. org / 10.1029 / AR 032 p 0095"]}

Among numerous ascidians, two colonies of the deep species Protoholozoa pedunculata Kott, 1969 were collected in 2017 by the French Poker 4 survey, Indian Ocean. The larvae of this species are described here for the first time. The present material shows the disposition of adhesive papillae in a line and incubation in the atrial cavity. That is different from what was first reported and from what is known in other species of the genus, which show triradiate adhesive papillae and incubation in a brood pouch. This new data leads us to discuss the taxonomic status of different species, leaving Protoholozoa Kott, 1969 for the previous ones and creating Scotiazoa gen. nov. for species with triradiate larval papillae and brood pouch.

Protoholozoa pedunculata Kott, 1969 (Figures 1���4) The examined colonies from the Poker 4 survey, have a soft vitreous tunic expanded in a cone above a thin peduncle (Fig. 1A,B). The zooids are parallel to each other with the siphons opening independently at the surface of the head on small protuberances (Fig. 1C,D). The thorax and abdomen have almost the same size (Fig. 2A,B). A long vascular post-abdominal process extends far into the colony peduncle. The rim of the oral aperture is slightly lobed with a weak sphincter. The atrial aperture is round and more or less dentate (Fig. 3A) at the base of the thorax. We counted up to 18 oral tentacles of two orders of size on a rod (Fig. 3A). The pre pharyngeal band is flat and dorsally curved to surround a button-like dorsal tubercle (Fig. 3A). The neural ganglion is close to the dorsal tubercle. About ten muscular fibres on each side, well-spaced, run obliquely on the thorax (Fig. 3A,B). There is no branchial sac. Inside the atrial cavity on each side there are two free transverse bridles attached to the endostyle at one extremity and joined dorsally to a vertical dorsal band (Fig. 3A,B), erect internally in two triangular papillae. These transverse bridles are linked to the medial side of the body wall by two thin strands of tissue. The abdomen is in direct prolongation of the thorax (Fig. 2A,B). The digestive loop is not twisted and has a rather long oesophagus followed by a round stomach with six longitudinal folds (Fig. 2A,B). The anus opens at the base of the thorax with two lobes. The massive gonad lies in the gut loop with numerous testis follicles and a central ovary (Fig. 2B). The sperm duct follows the rectum and opens close to the anus. A very long vascular process prolongs the abdomen. Several buds are present in the tunic at the abdominal layer (Fig. 1D) and posteriorly in the colony. One to four larvae are incubated inside the thoracic cavity at different stages of development (Figs. 2C,D; 3C; 4A,B). There is no brood pouch. The fully mature larvae measure 2.5mm for the trunk (Fig. 4A,B); they have an otolith but no ocellus. The tail is wound in �� of a turn. The three adhesive anterior papillae are placed in a median front line. Between them are two pairs of epithelial ampullae and another ampulla lies on each side of the adhesive papillae (Fig. 4A,B), for a total of 6 ampullae. The same larval shape is present (but was not described) in specimens from South Orkney Islands (Monniot & Monniot 1983) (Fig. 4C) and in specimens from the Scotia Arc (Fig. 4D), and confirms the species identity of the Atlantic and Indian colonies., Published as part of Monniot, Fran��oise & Tati��n, Marcos, 2020, Questions on the taxonomic status of species of Protoholozoa Kott 1969 (Ascidiacea Aplousobranchia, Holozoidae) with a description of a new genus, pp. 261-268 in Zootaxa 4718 (2) on pages 262-263, DOI: 10.11646/zootaxa.4718.2.7, http://zenodo.org/record/3602396, {"references":["Kott, P. (1969) Antarctic Ascidiacea. Antarctic Research Series, 13, 1 - 239.","Monniot, C. & Monniot, F. (1983) Ascidies antarctiques et subantarctiques: morphologie et biogeographie. Memoires du Museum National d'Histoire Naturelle, Paris, 125, 1 - 168."]}

Distaplia occidentalis Bancroft, 1899 Type B: Flat encrusting colonies Figure 6 B���G DHAK 02 BHAK 1687 Rattenbury Island ARMS vicinity, Scuba, 5.2 m. One colony, red, in two pieces. With hatching tadpoles. Part of colony flat, part with very short protruding lobes. DHAK 03 BHAK 1686 UF 2516. Mercury Islet ARMS vicinity, Scuba, 18 m. Light purple. IHAK 9 BHAK 0539 UF 2458. Shatner Point, Fifth Beach, low intertidal, rock benches, mussel/barnacle/algal walls/tidepools. Low tide, fast current; big flat thick slab, zooids in systems; no larvae. Dark purple on surface, internal tunic is white and somewhat flocculent. IHAK 12 Rocky intertidal across small bay from Hakai dock. One very small flat colony. IHAK 18 BHAK 0655 UF 2504. Underside of lab dock. One colony with yellow tunic. IHAK 18 BHAK 0659 UF 2508. Very large yellow rounded colony, about 9 cm in diameter. IHAK 22 BHAK 0660 UF 2509. Mercury Islet, Scuba, 5���15 m. Flat white colony but with narrow base wrapped around rock. IHAK 33 BHAK 1703 UF 2521. North Beach Nero Site, Scuba, 5 m. Orange-red encrusting. IHAK 37 Crazy Town surge channel, Scuba, 5 m. Red. IHAK 39 BHAK1708 UF 2524. NE Rattenbury Island, Scuba, 12 m. Bright orange, flat, 4 cm in longest dimension. IHAK 42 BHAK 1710 UF 2510. Starfish Rocky Reef Site, Scuba, 18 m. Orange and purple mixed. IHAK 43 Triquet, snorkel 5 m. Orange, purple and white. IHAK 60 BHAK 1740 UF 2551. Rattenbury Pinnacle, Scuba, 17���20 m. Orange and black. RHAK 6 BHAK 0628 UF 2479. Seventh Beach, North wall, low intertidal tide pool. Large white flat colony. Zooids only about 2 mm long. XHAK 9 BHAK 2831 UF 2554. Kelpie Point ARMS, Scuba, 5 m. Very small; zooids very contracted but about 20 stigmata/ side. The only morphological difference from Distaplia occidentalis type A is that these colonies are not mushroom shaped with a stalk; they are flat thick encrusting sheets in a wide variety of colors including many shades of purple, yellow, orange, red or white or even multiple colors, and may be up to 10 cm or more in diameter. Ritter & Forsyth (1917) comment on the two different growth forms: ���colony varying from flat and encrusting to pedunculated or mushroom-shaped with all gradations between.��� The zooids and tunic pigments are confined to the upper layer, the lower layer usually unpigmented, cream���colored and somewhat flocculent in texture. Fertilization, the details of which are unknown, is internal and the embryos are incubated in a brood sac which extends into the tunic but is attached to the parent zooid at the base of the thorax. The oviduct is long and extends to the end of the brood sac, which means that the youngest embryos are at the posterior end of the brood sac. In all forms of D. occidentalis there are never more than four embryos in the brood sac (Fig. 6F), and the parent zooid dies after completing ovulation, thus later in the breeding season a colony may contain only or primarily brood sacs with maturing embryos, the adult zooids having died and been resorbed. The mature embryos are large (the body near to 1 mm in length, Fig. 6G) and elongate, with three adhesive papillae in a triangular arrangement. Distribution and references same as for the mushroom-shaped colonies above., Published as part of Lambert, Gretchen, 2019, The Ascidiacea collected during the 2017 British Columbia Hakai MarineGEO BioBlitz, pp. 401-436 in Zootaxa 4657 (3) on pages 412-413, DOI: 10.11646/zootaxa.4657.3.1, http://zenodo.org/record/3371886, {"references":["Ritter, W. E. & Forsyth, R. A. (1917) Ascidians of the littoral zone of southern California. University of California Publications in Zoology, 16, 439 - 512."]}

Distaplia smithi Abbott & Trason, 1968 Figure 7A, B IHAK 50 BHAK 1724, 1725 UF 2536, 2537. Hakai Passage, Port Reef, Scuba, 21 m. RHAK 2 BHAK 0603 UF 2461. Goose Island group, Duck Island, low rocky intertidal. Immature colony. ZHAK 35 BHAK 3250 UF 2568. Sasquatch Commode tidepool. The unique arrangement of the zooids in double vertical rows can be seen though the translucent tan tunic in the enlarged heads of this stalked species. The orangeish colonies may reach a considerable size with numerous heads and stalks of variable length but often quite long, up to 8 cm. The tunic is smooth on both the stalks and expanded heads with no debris or epibionts. As in all species of Distaplia, the zooids have 4 rows of stigmata, each row crossed by a parastigmatic vessel. For detailed description see Abbott & Trason (1968) and Abbott & Newberry (1980). Distribution: Alaska to central California (Abbott & Trason 1968; Abbott & Newberry 1980; Lamb & Hanby 2005)., Published as part of Lambert, Gretchen, 2019, The Ascidiacea collected during the 2017 British Columbia Hakai MarineGEO BioBlitz, pp. 401-436 in Zootaxa 4657 (3) on page 414, DOI: 10.11646/zootaxa.4657.3.1, http://zenodo.org/record/3371886, {"references":["Abbott, D. P. & Trason, W. B. (1968) Two new colonial ascidians from the west coast of North America. Bulletin of the Southern California Academy of Sciences, 67, 143 - 154.","Abbott, D. P. & Newberry, A. T. (1980) Urochordata: the tunicates. In: Morris, R. H., Abbott, D. P. & Haderlie, E. C. (Eds.), Intertidal Invertebrates of California. Stanford, California, Stanford University Press, pp. 177 - 226 + P 57 - P 67.","Lamb, A. & Hanby, B. P. (2005) Marine Life of the Pacific Northwest - A Photographic Encyclopedia of Invertebrates, Seaweeds and Selected Fishes. Harbour Publishing, Madeira Park, BC., 398 pp."]}

A three-week intensive marine biodiversity survey was carried out at a small remote region of the central British Columbia coast at and near the Calvert Island Marine Station (Hakai Institute) July 21–August 11, 2017. The survey included daily sampling by the staff and a number of visiting taxonomists with specialties covering all the major groups of invertebrates. Many marine habitats were sampled: rocky and sand/gravel intertidal and tidepools, eelgrass meadows, shallow and deeper subtidal by snorkel and Scuba, plus artificial surfaces including the sides and bottom of the large floating dock at the Institute and settlement plates set out up to a year previously at various subtidal sites. Many new species were recorded by all the taxonomists. In this very biodiverse remote area 36 ascidian species were identified: 18 Aplousobranchia, 7 Phlebobranchia, and 11 Stolidobranchia, comprising a total of 15 solitary and 21 colonial species including two undescribed colonial species. This represents almost one third of all the known North American species from Alaska to southern California in this limited very remote area. Remarkably, only two are possible non-natives. Diplosoma listerianum (Milne-Edwards, 1841), was collected mostly on natural substrates including deeper areas sampled by Scuba, and one colony occurred on a settlement plate. A few Ciona savignyi Herdman, 1882 were collected, two from natural substrates and four from artificial surfaces. There were no botryllids, Styela clava Herdman, 1881, Didemnum vexillum Kott, 2002, or Molgula manhattensis (De Kay, 1843), though these are all common and sometimes very abundant non-natives in other parts of BC and along much of the U.S. west coast. Most of the species encountered are known in northern California, Washington, and southern BC, but only a small number are represented among the few known Alaska species.

The understudied deep-sea benthic communities from the Southwestern Atlantic continental slope (200 m–3000 m depth) were sampled on August 2012 in an area located around 38°S that included the Mar del Plata submarine canyon. In these samplings we found a total of 16 ascidian species from six different families, of which two corresponded to new species. These were: Aplidium meridianum (Sluiter, 1906); Aplidium variabile (Herdman, 1886); Aplidium marplatensis Maggioni & Tatián (sp. nov. present work); Aplidium solitarium Maggioni & Tatián (sp. nov. present work); Synoicum georgianum Sluiter, 1932; Synoicum molle (Herdman, 1886); Synoicum sp.; Polysyncraton trivolutum (Millar, 1960); Sycozoa umbellata (Michaelsen, 1898); Ascidia meridionalis Herdman, 1880; Cnemidocarpa drygalskii (Hartmeyer, 1911); Styela squamosa Herdman, 1881; Pyura pilosa Monniot C. & Monniot F., 1974; Molgula pyriformis Herdman, 1881; Molgula setigera Ärnbäck-Christie-Linde, 1938 and Asajirus indicus (Oka, 1913). Based on morphological evidence, we propose the new synonymy: Molgula setigera Ärnbäck-Christie-Linde, 1938 = Molgula marioni Millar, 1960 = Molgula robini Monniot C. & Monniot F., 1983. We also propose to maintain Molgula pyriformis and Molgula malvinensis as separate species. We report: the extension of the distribution range of Aplidium meridianum, Synoicum georgianum, Polysyncraton trivolutum, Sycozoa umbellata, Cnemidocarpa drygalskii, Pyura pilosa and Molgula setigera, being the first time they are collected off La Plata River; the deepest registers for Synoicum georgianum, Poylsyncraton trivolutum, Sycozoa umbellata, Ascidia meridionalis, Pyura pilosa, Molgula pyriformis and Molgula setigera; and the shallowest register for Synoicum molle. Fil: Maggioni, Tamara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina Fil: Taverna, Anabela Jesús. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina Fil: Reyna, Paola Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina Fil: Alurralde, Roque Gastón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina Fil: Rimondino, Clara Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina Fil: Tatian, Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina

Sycozoa umbellata (Michaelsen, 1898) References: Colella umbellata Michaelsen 1898: 371; Sycozoa umbellata Sluiter 1919: 12; Van Name 1945: 154, fig. 75 A–C (synonymy). Material examined: several colonies; net; -36.5433 lat. -53.3833 long. (station 5); 647 m; 10 August 2012 (Figures 9 A–B). Colonies consist of small heads supported by long, thin and frequently ramified stalks (Fig. 9A). On average, the heads measure 5.3 mm in length and 4.2 mm wide and are shaped in the form of ovoid masses. The stalks are smooth and extremely long. The average length of the stalks is 14 cm. Each stalk supports from one to three heads, though the most frequent configuration consists of colonies with two heads. The tunic is yellowish and transparent when alive. After conservation in formalin, it acquires a more opaque tone. Its consistency is soft in the heads and coarse in the stalks. Each head bears longitudinal rows of three to five zooids arranged in oblique or random-like configurations (Fig. 9B). On average, zooids are 1.9 mm in length. No larvae were found. Remarks. The general shape of the colonies (small rounded heads supported by fine peduncles arising from a basal mass of stolons) resembles the closely related species Sycozoa georgiana (Michaelsen, 1907). According to Van Name (1945), each head of S. georgiana is "supported on a separate peduncle that can reach 3 cm in length, but is usually much shorter" (154 p.). The peduncles of the present specimen, on the contrary, reach 14 cm in length, have ramifications and usually have two heads. On the other hand, S. georgiana is cited exclusively for the South Georgia Islands. Sycozoa umbellata, in addition to the South Georgia Islands, has also been recorded in the SW Atlantic, near the area where the colonies of the present work were collected. Van Name (1945) also notes that S. umbellata is closely related to S. sigillinoides Lesson, 1930, of which it is distinguished by "the usual reproduction of numerous heads of the upper part of the peduncle or of broken or injured places along its length, and also fragments of peduncles" (154 p.). In addition, the length of the heads and consequently, the number of zooids per head in S. sigillinoides, is greater. The only reliable characters to distinguish among these three species and Sycozoa gaimardi (Herdman, 1886), all with overlapping distribution ranges, are external: the appearance of the colony and the shape and size of the heads. Table 3 lists such differences in detail. This is the deepest and northernmost record for the species., 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 15-17, DOI: 10.11646/zootaxa.4526.1.1, http://zenodo.org/record/2611359, {"references":["Michaelsen, W. (1898) Vorlaufige Mitteilung uber einige Tunicaten aus dem Magalhaensischen Gebeit sowie von Sud Geogien. Zoologischer Anzeiger, 21, 363 - 372.","Sluiter, C. P. (1919) Uber einige alte und neue Ascidien aus dem Zoologischen Museum von Amsterdam. Bijdragen tot de Dierkunde, 21 (1), 1 - 12.","Van Name, W. G. (1945) The North and South American ascidians. Bulletin of the American Museum of Natural History, 84, 1 - 146.","Michaelsen, W. (1907) Tunicaten. Ergebnisse der Hamburger Magalhaensischen Sammedreise, 1892 - 1893, Hamburg, 1, 1 - 84.","Herdman, W. A. (1886) Report on the Tunicata collected during the Voyage of H. M. S. Challenger during the years 1873 - 76. Part II. Ascidiae compositae. Report of the Scientific Results of the Uoyage of H. M. S. Challenger during the years 1873 - 76, 14 (38), 1 - 399."]}

This study is the first inventory of ascidians from shallow waters (0–25 m) of coastal and reef habitats in the southern Gulf of Mexico where ascidian diversity is poorly known. Sampled environments in 14 locations (38 sites) with 134 samples collected from 2015 to 2017 included coral reefs, coastal lagoons, mangroves, seagrass, ports, and artificial platforms. The 31 identified species comprise 19 genera and 13 families. Ten species are newly reported in the Gulf of Mexico:AscidiapanamensisBonnet & Rocha, 2011;Ecteinascidiastyeloides(Traustedt, 1882);CystodytesroseolusHartmeyer, 1912; Eudistomaaff.amanitum Paiva & Rocha, 2018;EudistomarecifenseMillar, 1977;EuherdmaniafasciculataMonniot, 1983; Euherdmaniaaff.vitrea Millar, 1961;Polycarpacartilaginea(Sluiter, 1885);Botrylloidesmagnicoecum(Hartmeyer, 1912) andDidemnumgranulatumTokioka, 1954. Two new species will be described separately (Clavelinasp. andPyurasp.). This study provides the first records for 26 species ascidians for the region as well as describes increased distributions of ten Atlantic species. Thus, our data provide a starting point for future ecological, experimental and taxonomic studies of ascidians of the Gulf of Mexico.

Distaplia matua n. sp. (Figure 13) Material examined. Holotype: KBPGI 1451 /1, Kuril Islands, Matua Island, Point Kluv, 15 m, 25.08.2016. Paratypes: KBPGI 1452 /2, Matua Island, Point Kluv, 15 m, 22.08.2016, one colony and KBPGI 1453 /3, same locality, 26.08.2016, one colony. Description. The holotype (in formaline) is a dirty-brown, dark and an almost flat crust with glossy shinning surface, about 6 cm in diameter and up to 10 mm thick (Figure 13 D). The test is firm, cartilaginous, not spongy in consistence, opaque, free from foreign particles on surface and inside. Position of each zooid is marked by branchial openings, but zooids are not visible through the test and the systems are not recognizable. In live the colonies look completely different (Figures 12 A–C). They form low, wide, reddish or, sometimes, carmin red cushions, attached to substratum by the whole wide lower surface. The branchial openings of zooids are large and crowded, six-lobed, distributed evenly along the whole surface of the colony. Common cloacal openings are on the tops of short and wide siphons, situated, sometimes, on the slightly raised parts of the colony (Figure 12 A). Common cloacal siphons have lobed margin. The zooids, with strongly contracted thoraces, are about 3.5 mm long. They are deep-brown, or sometimes black-brown, opaque. The branchial siphon, when not contracted, is conspicuous, with six short lobes. Atrial opening is wide, in live all four rows of stigmata are exposed to the cloacal cavity, in contracted zooids it may be slit like. The longitudinal thoracic muscles are very numerous, crowded and difficult to count, approximately about 30 on each side. The circular muscles on the branchial siphons are well developed. The branchial tentacles usually, but probably not always, are distributed in a following way: three tentacles of the first size order are the longest (one dorsal and two ventro-lateral), between them are inserted three medium sized tentacles of the second size order, and there are several minute tentacles of the third size order. The stigmata are in four rows grouped by two (as in Sycozoa). We counted about 14–17 stigmata in the middle rows but about 18–19 in the first row. The parastigmatic vessels are not discernible and probably absent. The oesophagus is long, its distal end bent at almost right angle to enter the stomach. The compact asymmetric obliquely oriented stomach is in the posterior half of the abdomen, on some distance from its posterior end. Stomach wall has numerous (about 20 or more) rather regular longitudinal folds (Figure 12 E). The subdivision of the intestine is not pronounced and obscured by opaque wall of zooid. The gastric reservoir is present. The gonad is in the abdomen on the right side of the gut loop, not in the protruding sac, contains several (up to 10 were counted) oval male follicles, and one to three ova. Several zooids have minute brood pouch which just start to develop and contains no ova yet. The colonies contain no larvae. Remarks. The species of the genus Distaplia, known from the region include: one species, D. alaidi, known from Kurile Islands only, two species, D. rzhavskii Sanamyan, 1993 and a species recorded as Distaplia sp. aff. clavata (Sars, 1851) by Sanamyan (1993) known from Kamchatka waters, and one species, D. dubia (Oka, 1927) from Sea of Japan. Distaplia dubia is very common on sea algae in the vicinity of Vladivostok. Distaplia unigermis Ivanova- Kazas, 1965 is probably its synonym. We had chance to examine many colonies of D. dubia, they are either whitish or greenish, small, often composed of several separated systems (exactly as figured by Nishikawa, 1990, Figure 9) and in overall are very different from the present species. In the preservative they remain whitish and not become deep-brown as D. matua n. sp. Distaplia rzhavskii has a colony composed of several closely placed upright lobes. Sanamyan (1993) pointed to transverse thoracic muscles as to a significant taxonomic feature of this species, but this may be connected with a way thoraces contracted during fixation and should be confirmed. The shape of the colony, however seems to be distinctive. Also, D. rzhavskii has areolated stomach, rather than longitudinally folded in D. matua n. sp. Distaplia sp. aff. clavata: Sanamyan, 1993 has massive colony attached by a small point. Most probably it has no relation with D. clavata (Sars, 1851) and the colony, as well as the zooids with areolated stomach, differ distinctly from D. matua n. sp. The species from Alaska, D. alaskensis Lambert et Sanamyan, 2001, also has different colony, composed of club shaped lobes and different zooids with finely areolated stomach. Distaplia matua n. sp. appears to be most closely related to Distaplia colligans Sluiter, 1932, which also inhabits cold waters but in a geographically distant region, Magellan Islands and Antarctic Peninsula. The colonies of this species are flat, encrusting and dramatically change colour from bright yellow in live to deep-brown or almost black in preservative (see Sanamyan, Schories, 2003). The zooids have fine longitudinal plications on the stomach wall.

Distaplia alaidi Sanamyan, 1993 (Figure 12) Distaplia alaidi Sanamyan, 1993: 170. Material examined. Matua Island, Point Kluv, 15 m, several specimens in two lots (#77, 157). Description. Colony consist of one, two, or rarely three spherical or oval heads, up to 1.5 cm diameter, but usually less than 1 cm, supported on a thin, no more than 4 mm diameter, long (up to 4 cm) stalk. The stalk is sharply demarcated from the head. Its basal part creeps along the branches of hydroids and bryozoans to which it is attached. In formaline the colonies are opaque white, soft, with zooids indistinctly visible from the exterior. The surface is clear, some sand grains occasionally present on the stalks. Underwater photographs (Figures 12 B���D) reveal the peculiar structure of the colonies, totally obscured on preserved specimens. Each head contains a single system of zooids. A single large cloacal opening is on the top of each head. Its diameter is rather large and attains one third of the diameter of the head (in live state). The margin of the cloacal cavity is surrounded by the prominent round lobes, about 10 of them may be counted on some photographs. The cloacal cavity is very spacious, thoraces of almost all zooids in the head, with all four rows of stigmata completely exposed into the common cloacal cavity, can be easily seen through the cloacal opening. The zooids in the head stand almost vertically, with their dorsal sides facing to the axis of the colony. Branchial openings of individual zooids open on the surface of the upper half of the head, each opening is on the top of unusually long and wide thin-walled plain-edged siphon rising above the surface of the head and bent down (ventrally) (Figure 12 D). Zooids, with significantly contracted thoraces (in formaline) are about 6 mm long. The stigmata are very long, about 26 counted in the middle rows on each side of the branchial sac. Each row is crossed by a thick parastigmatic vessel. Four rows of stigmata are not grouped by two (as in Sycozoa). The stomach is large, voluminous, asymmetrical, with its ventral side being longer than the dorsal, clearly demarcated from the intestine, contrasting deep-red in live specimens (visible on a smaller colony on Figure 12 B). Stomach wall presents small rounded swellings (or areolations) sometimes fused together and arranged in irregular longitudinal lines (Figure 12 E). Gonads, consisting of rather numerous male follicles and several large ova are in the sack protruding from the posterior end of the abdomen. The examined colony contained numerous long brood-pouches located at the base of the colony head, below the zooids. The brood pouches are connected with the zooids by very long narrow connective, which is longer than the length of the zooid and easily tear when the zooids are extracted. They contain from one to five developing eggs in a single row, but no larvae were found. Remarks. The species was known previously only from original description based on two specimens from Atlasova Island (which belongs to north Kuril group of islands). Sanamyan (1993), having only preserved specimens, failed to recognize the structure of the systems and a peculiar shape of the colony with long ventrally bent branchial siphons protruding from the colony surface. Current record from central Kuril Islands, where it is probably not rare, extends its known geographic range to the south. The species most probably is an endemic for Kuril Islands���during many years of investigation we saw no similar colonies in Kamchatka waters, and nothing similar is known from more southern locations. The species cannot be confused with any other Distaplia species or other colonial ascidian known from the region., Published as part of Sanamyan, Karen & Sanamyan, Nadya, 2017, Shallow-water Ascidians from Matua Island (central Kuril Islands, NW Pacific), pp. 301-321 in Zootaxa 4232 (3) on pages 316-318, DOI: 10.11646/zootaxa.4232.3.1, http://zenodo.org/record/293689, {"references":["Sanamyan, K. (1993) Pseudoplacentela smirnovi gen. et sp. n. (Tunicata, Ascidiacea), with a discussion of its phylogenetic relationships. Zoologica Scripta, 22 (3), 305 - 307."]}

Sanamyan, Karen, Sanamyan, Nadya (2017): Shallow-water Ascidians from Matua Island (central Kuril Islands, NW Pacific). Zootaxa 4232 (3): 301-321, DOI: https://doi.org/10.11646/zootaxa.4232.3.1

Sanamyan, Nadya (2017): Shallow-water Ascidians from Matua Island (central Kuril Islands, NW Pacific), part 2. Zootaxa 4337 (1): 121-131, DOI: https://doi.org/10.11646/zootaxa.4337.1.6

Distaplia colligans Sluiter, 1932 Fig. 2 References and synonymy: Distaplia colligans Millar (1960) p. 77; Kott (1969) p. 32; Sanamyan & Schories (2003) p. 94. Localities: 1 S, 2 S, 3 S, 6 S, 9 S. The species forms crusts ca. 5 mm in thickness of a bright yellow colour. Cloacal apertures are slightly raised over the colony surface, but no conspicuous zooid systems are visible. The tunic is soft and free of sand. The zooids measure up to 3 mm. The atrial aperture is large with an anterior lip. The branchial sac has 4 stigmata rows with about 20 stigmata per half-row. A parastigmatic vessel cuts each row. At least 8 fine longitudinal muscles are counted at each side of the thorax. The abdomen is small, comprising the digestive loop with an elongated stomach whose surface is slightly wrinkled. The gonads lie in the centre of the intestinal loop, comprising several male follicles and a central mass of a few oocytes. There were larvae in the colonies, apparently free in the tunic. They measure 1���1.5 mm of trunk length and bear an oozooid and three adhesive papillae. The stalks of the papillae had two lateral outgrowths in the ventral papilla and one each in the two dorsal papillae. Remarks. This species is widely distributed in Antarctic and subantarctic waters (Monniot & Monniot 1983, 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 154, DOI: 10.11646/zootaxa.4093.2.1, http://zenodo.org/record/267667

Monniot, Françoise (2016): Ascidians (Tunicata) of the French Guiana Expedition. Zootaxa 4114 (3): 201-245, DOI: http://doi.org/10.11646/zootaxa.4114.3.1

Distaplia bermudensis Van Name, 1902 Figure. 11. Stations. SR 5; SR 8; SR 12; SR 13; SR 14; SR 19; SR 20; SS 2; SS 4; SS 5; SS 10; SS 11; SS 12; SB 2; SB 3; SC 7; SC 9; SD 8. Numerous colonies with varied shapes, in cushions or sheets, were settled on all kinds of substrates, some on ascidians. The tunic is very soft, pale or greyish in formalin but of a bright pink in life. (Fig. 11 A).The surface tunic is easily torn and often in shreds. The zooids are arranged in stellate systems. The atrial languet is simple or with a dented tip above a wide open siphon. The 4 rows of stigmata are crossed by a parastigmatic vessel. The stomach is round with a smooth wall. A large oocyte is placed against a clump of testis vesicles inside the gut loop. One or 2 larvae are appended in a thoracic pouch. They are 1.2 mm in length with a tail in a half circle (Fig. 11 B). This shallow species is widely distributed in Bermuda, Florida, Caribbean islands and Brazil (Rocha et al. 2005) and recently introduced in the Mediterranean (Mastrototaro and Brunetti 2006)., Published as part of Monniot, Fran��oise, 2016, Ascidians (Tunicata) of the French Guiana Expedition, pp. 201-245 in Zootaxa 4114 (3) on page 216, 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.","Mastrototaro, F. & Brunetti, R. (2006) The non-indigenous ascidian Distaplia bermudensis in the Mediterranean: comparison with the native species Distaplia magnilarva and Distaplia lucillae sp. nov. Journal of the Marine Biological Association U. K., 86, 181 - 185. http: // dx. doi. org / 10.1017 / s 0025315406013014"]}

30 páginas, 15 figuras, 2 tablas, We studied the ascidian fauna from two zones located in subantarctic (Punta Arenas, latitude 53º) and temperate Chile (Coquimbo, latitude 29º). The different oceanographic features of the two zones, with influence of the Humboldt Current in the north and the Cape Horn Current System and freshwater inputs in the south, led to markedly different ascidian faunas. A total of 22 species were recorded, with no shared species across the two areas (11 species each). The new species Polyzoa iosune is described, Lissoclinum perforatum is found for the first time in the Pacific Ocean, and Synoicum georgianum and Polyzoa minor are new to the Chilean fauna. The populations of Ciona in the Coquimbo area (formerly attributed to Ciona intestinalis) correspond to the species Ciona robusta. A total of 35 Cytochrome oxidase (COI) sequences of the standard barcode region have been obtained for 17 of the 22 species reported., This research was funded by CONICYT Chile (Grant 80122006). Additional funding was obtained by XT from the Spanish Government (project CHALLENGEN CTM2013-48163) and by JIC from University of Magallanes: UMAG/DI&P Grant PR-F2-01CRN-12, CIMAR 18 & CIMAR 20 Fjords Chilean Navy, and GAIA-Antarctic Project (MINEDUC-UMAG). RMR received a research grant from CNPq–National Counsel of Technological and Scientific Development (304768/2010-3).

A collection of ascidians from 100–1000 m deep off the north-western coast of Australia has yielded 19 species, including one new, two possibly endemic to the north-western coast of Australia, four well-known Indo-west Pacific tropical species and 12 species known from the deeper waters of the western Pacific, of which 11 had not previously been recorded from off the western Australian coast or from other parts of the Indian Ocean. A third of these 12 species displays adaptations for a reduction in filter-feeding capacity, as do other known species from deeper slope and abyssal habitats. Nevertheless a connection with fauna of deep ocean basins of the Indian Ocean is not apparent at this stage. The full range of characters associated with species, genera and families are discussed, and those contributing to the identification of immature or mutilated specimens, as well as those relevant to an assessment of phylogenetic relationships, are emphasized.

Fifty-one species are discussed of which five are new. Of the remaining 46 species, 20 previously known from one to three records and 11 more frequently recorded have their known geographic range and/or range of morphological variation extended and the synonymy of a further 15 species is revised. Taxonomic problems, including phylogeny, are addressed in Rhopalaea crassa, Pycnoclavella detorta, Ecteinascidia spp. and Plurella (see Phallusia polytrema). New species are Sigillina pulvinus, Polyclinum corbis, Perophora longicaulis, Stolonica brevigastra and Botrylloides saccus.

Thirty-four species of benthic Tunicata are recorded in the deep-water material collected from 255 to 8116m from the south-western Atlantic, Scotia and Weddell seas. Maximum species diversity occurs at between 4000 and 6000 m. Unlike the north Atlantic, large forms predominate. However, that there are only a few species less than 5 mm is probably the result of the collecting method. Some species appear to form crowded populations of numerous specimens, as evidenced in the records of approximately 400 specimens of Agnezia at 7694–7934m and 150 large specimens of Dimeatus at 5680–6145 m. Six new species are described, of which one is recorded from more than 8000 m. This is one of the greatest depths yet recorded for ascidians, the only other species recorded below 8000 m is Situla pelliculosa Vinogradova, 1969.

Lagger, Cristian, Tatián, Marcos (2013): Two new species of Distaplia (Tunicata: Ascidiacea) from the SW Atlantic, Argentina. Zootaxa 3620 (2): 192-200, DOI: http://dx.doi.org/10.11646/zootaxa.3620.1.10

Distaplia naufragii sp. nov. (Figures 2 A, B, C; 3 A, B) Material examined. Las Grutas (Río Negro), Argentina. Holotype: MZUC T00005, one colony ( Fig. 2 B ) sampled on 30 /X/ 2011 at 20 m depth from the shipwreck “Don Félix” (40 ° 51.784 S; 65 ° 0 3.802 W). Paratypes: MZUC T00006, six colonies: 40 ° 51.784 S; 65 ° 0 3.802 W; 30 /X/2011, 20 m. Etymology. From naufragii, the genitive of the latin noun naufragium (= shipwreck). Description. Small colonies consist of several mushroom-shaped lobes joined by short yellowish peduncles. Large colonies are composed of a cushion shaped lobe, which may reach 6.5 cm long by 4.5 cm high, attached to the substratum by a pale yellow small area. The basal portions of the colonies are burgundy colour while the upper layer of the tunic is semi-transparent allowing the observation of white pigment granules on the oral siphons of each zooid. The test is soft and free of epibionts. The zooids are perpendicular to the colony surface and organized in circular or elongated systems containing up to 25 zooids which converge into common cloacal aperture. The thoraces of the zooids are prominent and located in the uppermost layer of the tunic. Living colonies are easily recognizable underwater by the contrast between of burgundy basal area of the tunic and the white prominent zooids (Fig. 2 A). The zooids are large, reaching 5 mm or more in length when well expanded. The oral siphon, surrounded by abundant circular muscles, is smooth-edged or forming six sinuate lobes. The atrial aperture is wide, exposing much of the pharynx, and has a dorsal languet with plain edge. The thorax bears about 40 thin oblique muscles (many of these are branched) on each side, most of which are concentrated around the opening of the atrial aperture. There are 15 to 21 thread-like oral tentacles of two sizes, arranged regularly in a single circle. The dorsal tubercle is small and circular, with an aperture of similar form. The four rows of long stigmata are crossed by well-developed parastigmatic vessels. There are about 18 to 21 stigmata in each half row. Three dorsal languets are displaced to the left side of the thoracic midline. The slightly curved oesophagus connects to the stomach laterally. The oval stomach has conspicuous internal longitudinal ridges. Ridges are often curved, somewhat irregular or interrupted, giving a stretch-marked external appearance to the stomach wall. A pyloric gland extends between the stomach and the intestine. The intestine has a constriction situated at a short distance beyond the stomach. The bi-lobed anus opens at the level of the third row of stigmata. The zooids are hermaphroditic. Gonads occupy the right side of the gut loop and consist of 8 to 15 male follicles and an ovary containing 7 to 9 oocytes of different sizes (one or two of them are large), situated mainly below the testis. The fine vas deferens ends at the same level as the anus. The brood pouch projecting from the thorax, at the level of the fourth stigmata row, contains up to 6 developing larvae. The oval larval trunk may be up to 1.4 mm long. The larvae possess three adhesive papillae triangularly arranged; ampullae and epidermal vesicles were not observed. The tail is on the same level of the adhesive papillae and involves half or less of the larva. Each sensory vesicle contains both an otolith and an ocellus.

Distaplia fortuita sp. nov. (Figures 2 D; 4 A, B) Material examined. Las Grutas (Río Negro), Argentina. Holotype: MZUC T00003, one colony ( Fig. 2 D ); washed ashore on sand beach off Las Grutas; 18 /XI/ 2005. Paratypes from type locality: MZUC T00004, one colony; 18 / XI/ 2005. Etymology. From fortuita latin adjective meaning casual, by chance. Description. Both colonies are almost spherical in shape. The holotype, the larger of the two available colonies, is up to 4 cm in length, with a small flat basal area. The cherry red colour of fresh colonies quickly faded when fixed in formalin. The tunic is soft and smooth without any incrustations. The pale zooids that may be seen through the tunic are organized in circular or elongated systems of up to 15 individuals. The zooids reach a maximum of 2.8 mm but most are approximately 2 mm long. The elongated oral siphon is narrow but gets wider closer to the aperture, without lobes (smooth-edged) and with very few circular muscle bands. The atrial siphon exhibits two possible shapes: the most frequent is a tube-shaped siphon that projects upwards, with a slightly elongated upper margin. The other shape is a short siphon with smooth edge and situated close together with the oral siphon at the upper part of the thorax. Each side of the thorax bears about 25 thin oblique muscles that extend from the ventral region to the dorsal line. There are about five to seven very small oral tentacles arranged in a circle. The pharynx has four rows of 15- 17 stigmata per side and are crossed by parastigmatic vessels. The aperture of the oesophagus is broad and the oesophagus enters the stomach laterally. The obliquely oriented stomach is oval and has an almost smooth wall, with some longitudinal fine stretch marks on its internal wall (not always noticeable). There is a constriction between the duodenum and the mid-intestine, but it is not possible to see unless gonads are removed. A pyloric ampulla, clearly visible above the gonads, extends between the stomach and the intestine. The bi-lobed anus opens at the level of the third row of stigmata. All zooids of the two colonies are males. Testis consist of a cluster of 13 to 22 circular or oval-shaped follicles that lie beside the intestinal loop. The straight sperm duct originates from the centre of the testis and it opens near the anus. Some zooids possess a very small curved brood pouch (it was never developed). The mature larvae lie in the upper layer of the colony; they are of a rounded shape and may be up to 1.4 mm long but are generally shorter (about 1.2 mm). The larval tail wraps in a half circle around the trunk, ending at the level of the adhesive papillae. Larvae have three adhesive organs arranged in triangle and their sensory vesicles each contain an otolith and an ocellus. Discussion Both Distaplia fortuita and D. naufragii have similar cushion-shapes, although the smaller colonies of D. naufragii can also be mushroom-shaped. Despite the external similarity, the appearance of both species differs in colouration, size of the colonies and number of zooids surrounding the common cloacal opening. The zooids of Distaplia fortuita and D. naufragii are easily distinguished. The measurement of zooids revealed that those of D. fortuita are two or three times smaller than D. naufragii. In the former species, there are very few circular muscle bands around the never-lobed oral siphon, while in the latter the zooids show a strong circular musculature in the usually sixlobed oral siphon. The atrial siphon in D. fortuita is smaller and more closed than D. naufragii. Furthermore, Distaplia fortuita has fewer oral tentacles, thoracic muscles and stigmata than D. naufragii. Finally, D. fortuita contains more testis follicles than D. naufragii. Both species have internal longitudinal ridges, but these are more evident or marked in D. naufragii. While zooids of D. fortuita do not possess fully developed brood pouches, zooids of D. naufragii possess elongated brood pouches containing numerous developing larvae. The two colonies of D. fortuita were exclusively males. However, the presence of an undeveloped brood pouch suggest that there is a female phase at some time, probably after regression of the male phase. Although the larvae of both species are of similar size, they differ somewhat in the shape of their trunk, in that the larval thorax of D. naufragii is more elongated than that of Distaplia fortuita. A total of ten species belonging to the genus Distaplia have been reported in the Atlantic shallow waters (Rocha et al. 2012). Distaplia bermudensis Van Name, 1902 commonly forms an incrusting sheet with a thickness that varies between 2–7 mm. D. bermudensis has a smooth stomach, few testis follicles and oocytes, all located inside the intestinal loop, and a smaller larval trunk (0.8–1 mm). The species, common and widely distributed in the Caribbean (Van Name 1945), was also found in South eastern and Southern Brazil (Rocha & Costa 2005) and was also considered a relatively recent immigrant in the Mediterranean Sea (Mastrototaro & Brunetti 2006). Distaplia stylifera (Kowalewsky 1874) is distinguished from the other West Atlantic Distaplia species by its characteristic pear-shaped or oval sac-like postabdomen (containing the reproductive organs) which connects to the abdomen by a very narrow and elongated neck. The species, widespread in the Caribbean, was also found on artificial substrata in São Paulo State, Brazil (Rocha et al. 2011). Other two Distaplia species were recorded in the Caribbean: Distaplia corolla Monniot, 1974 and Distaplia crassa Monniot, 1983. Both species have a smooth walled stomach and neither have internal longitudinal ridges or fine marks, a clear diagnostic characteristic of the two new species presented in this paper. Furthermore, colonies of D. corolla are bright yellow or orange in colour and form cylindrical isolated lobes with zooids arranged in a ring, like a rosette. D. crassa have intestines without any morphological differentiation along their length and their ovaries are situated in the centre of the rosette of male follicles; thus, the gonads are entirely contained in the intestinal loop (Monniot 1983), differing from Distaplia fortuita and D. naufragii. Two Distaplia species have been reported from the North Atlantic: Distaplia clavata (Sars, 1851) and Distaplia rosea Della Valle, 1881. D. clavata consist of clavate or narrowly capitate colonies, sometimes with more than one head arising from a common expanded base, or occurring as flattened incrusting forms (Van Name 1945). According to Van Name (1945), Huntsman (1912) described living colonies as light yellow. The zooids of D. clavata share some characters in common with D. naufragii, including the size of zooids, the number of stigmata and the presence of ridges on the stomach wall (that are not very conspicuous, in contrast to D. naufragii). However, the figure drawn by Sars (1851) depicts a smaller cloacal siphon opening, fewer muscle fibres in the oral siphon and the thorax, a very robust vas deferens and indicates that all gonads lie over the intestinal loop, between the stomach and the mid-intestine (for comparison see Fig. 69 in Van Name, 1945). Inconspicuous colonies of D. rosea may be recognized not only by their characteristic rose-pink colour, but also by the peculiar soft sticky consistency of their tunic (Berrill 1950) D. rosea has fewer stigmata per row than our colonies. These two species recorded from the North Atlantic have external morphological characteristics completely different from the current samples. Within the South East Atlantic, the slightly stalked colonies of Distaplia capensis Michaelsen, 1934 have zooids with only 7–9 stigmata per half row in the branchial sac. In Distaplia skoogi Michaelsen, 1924, like D. stylifera, the gonads are in a pedunculate pouch behind the abdomen, with the testis vesicles clustered around a central ovary (Monniot et al. 2001). The presence of two round ampullae at the base of each papilla is also a diagnostic feature in the small larvae of this species and is absent in the larvae of our species. Only two Distaplia species have been recorded in the SW Atlantic to date. Distaplia cylindrica (Lesson 1830) is a circumpolar Antarctic species common not only in the Magellan area and the Patagonian shelf (Millar 1960; Sanamyan & Schories 2003), but also present up to 49 º latitude south in the Pacific Ocean (Tatián & Lagger 2009). The externally observable cylindrical rods and the soft consistency of this species make it distinctive such that its identification could not be confused. The other Distaplia species recorded in the tip of South America (Strait of Magellan) and South Georgia Island is Distaplia colligans Sluiter, 1932. Its low and flattened encrusted colonies form thin sheets and its tunic is glassy gray or yellow (Sanamyan & Schories 2003). Distaplia arnbackae Sanamyan et al. 2010 is a new species from the Pacific Ocean (Central Chile). Colonies of D. arnbackae are red in colour, but different from the present colonies: younger colonies consist of several small button shaped cormidiums containing mostly a single zooid system, while larger colonies are always encrusting sheets or flat cushions that rarely reach more than 5 mm thickness. There are no other Distaplia species similar to the material here described. The morphology of the colonies and of the zooids justifies the proposal that they represent two new species. As was stated, the SW Atlantic (Argentine Sea) is among the poorly known marine regions in terms of biodiversity (Orensanz et al. 2002). In the last ten years, several reports on the emergence of marine invasive, exotic and cryptogenic species in this vast region were published (Casas et al. 2004; Hidalgo et al. 2005; Penchaszadeh et al. 2005; Spivak et al. 2006; Calvo-Marcilese & Langer 2010; Tatián et al. 2010; Boltovskoy et al. 2011; Fiori et al. 2012). Today, non-native ascidians are increasingly being documented throughout world (Shenkar & Swalla 2011). However, even knowing that ascidians have been recently involved in many cases of bioinvasion (Lambert 2007, 2009), little is known about the diversity and distributions of ascidians in the Argentine Sea. The current results emphasize the need to increase the sampling effort for this group, and reinforce the importance of new studies in this area, considered pristine, but actually susceptible to biological invasions. Ascidian richness within the San Matias Gulf, examined by sampling for the first time using SCUBA diving, will be presented in a future publication.

The ascidian fauna from the Southwestern Atlantic (Argentine Sea) have scarcely been studied and have rarely been sampled. The existing scanty ascidian records are from specimens collected by dredging many decades ago. During samplings in the San Matias Gulf (Río Negro, Patagonia), two new Distaplia species were found. Distaplia naufragii sp. nov. was collected in the subtidal zone attached to a shipwreck, while the other species, Distaplia fortuita sp. nov. was found released by the tides in the sandy intertidal zone. These two new species differ deeply from each other in the size and morphology of their zooids. They represent one third of the known species belonging to the family Holozoidae in the SW Atlantic. These results reinforce the importance of new studies in this extensive but little explored area that is, in addition, susceptible to invasion by non-native species. Fil: Lagger, Cristian Fabian. Universidad Nacional de Cordoba. Facultad de Cs.exactas Fisicas y Naturales. Departamento de Diversidad Biologica y Ecologica. Cat.de Ecologia Marina; Argentina Fil: Tatian, Marcos. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Instituto de Diversidad y Ecologia Animal; Argentina

Surveys of littoral invertebrates along the southern coast of Madagascar have produced the first study of ascidians in this part of the Indian Ocean. Collections were made by SCUBA divers in May and June 2010 down to 25m depth. This region is considered the southern limit for coral reefs but remains diverse biologically. Upwellings and an abundant plankton community particularly favour the abundance of ascidians in this area. Of the 39 species of non-didemnid species described here, eight are new. Ten species are common to South Africa. Other species were for the most part already known from the Mozambique Channel and a few have also been recorded in the western Pacific (either cosmopolitan or introduced).

Distaplia stylifera (Kowalevsky, 1874) (Figure 27 B) Didemnum stylifera Kowalevsky 1874: 43, Red Sea Distaplia stylifera: Kott 1990: 127 fig. 46 pl. 9 f���g, and synonymy. Monniot F. & Monniot C. 2001: 258 fig. 119 C. and synonymy, widely distributed Stations. TA 52 (MNHN A 3 DIS 104). TA 60 (MNHN A 3 DIS 103). Three colonies, one with a short peduncle and two others sessile, the largest 15mm in diameter, have kept their orange colour in formalin. The consistency of the tunic is spongy, the pigment is limited to the upper part of the colonies. The zooids form circular systems. They are small and contracted, colourless. The atrial languet is large and wide. The 4 rows of stigmata lack parastigmatic vessels. The gut loop is wide with a short stomach asymmetrical and longitudinally folded. A well marked annular widening takes place between the stomach and the intestine. The gonads hang below the abdomen (Fig. 27 B). The testis has 5 to 6 vesicles in a rosette; the sperm duct (Fig. 27 B) begins with a deep loop directed posteriorly to encircle the single oocyte before running upwards to the gut loop. No larvae are present in these small colonies. The genus Distaplia as opposed to Sycozoa is defined as having parastigmatic vessels in the branchial sac and this is not the case here. Kott (1990) mentioned that the parastigmatic vessels are sometimes missing in D. stylifera which has a very constant anatomy around the world. D. stylifera is recorded in many places in the Pacific and Atlantic oceans, in the Red Sea, but for the first time here in the western Indian Ocean., Published as part of Monniot, Fran��oise, 2012, Some ascidians from the southern coast of Madagascar collected during the " AtimoVatae " survey, pp. 1-42 in Zootaxa 3197 on page 33, DOI: 10.5281/zenodo.246182, {"references":["Kowalevsky, A. (1874) Ueber die knospung der asciden. Archiv fur Mikroscopische Anatomie.","Kott, P. (1990) The Australian Ascidiacea. Part 2, Aplousobranchia (1). Memoirs of the Queensland Museum, 29 (1), 1 - 266.","Monniot, C., Monniot, F., Griffiths, C. L. & Schleyer, M. 2001 South African ascidians; Annals of the South African Museum, 108 (1), 1 - 141."]}

A large collection of ascidians was made during the CEAMARC Aurora Australis V3 cruise off Terre Adélie and George V Land a region rarely investigated before at these depths. Sampling was performed by beam trawls and a dredge between 138°– 146° latitude East and from 150 to 1700 m depth, on the Antarctic shelf and slope. Three of the 33 ascidian species identified are new and belong to the Stolidobranchia. Half of the species have an exclusive Antarctic distribution, others also occur in Sub-Antarctic areas, but none are common with the southern temperate fauna. The CEAMARC collection does not contain the whole range of already known species from this region. Moreover, brittle and very small specimens were not collected. COI sequences were obtained for 37 specimens, including two of the new species.

Holozoidae Distaplia colligans Sluiter, 1932 Sluiter, 1932: 7. Millar 1960: 77. Kott 1969: 32 and synonymy. Sanamyan & Schories 2003: 94 figs 3 C, D, 4, and synonymy. Stations: 5���17. The soft spongy colonies are poorly preserved. They form flat cushions or settle in sleeves around hard polychetes tubes. Colourless in fixative liquids, the colonies may have been yellow in life as bright yellow cushions can be seen on the video recorded on board during the sampling. This is also suggested by the color photos given by Sanamyan and Schories (2003 Fig. 3 C, D) for this species. The zooids in less damaged colonies have 4 rows of stigmata crossed by parastigmatic vessels. The atrial languet is either pointed or dentate. The stomach wall has numerous thin ridges. The ovary is placed in the centre of a ring of testis vesicles. One or two not completely developed embryos hang in a brood pouch. The anatomical differences with D. cylindrica are limited to the colony shape. One sequence for specimen A 3 DIS 100 (BOLD: ASCAN 015��� 10). Divergence from A 3 DIS 98 (D. cylindrica) is very small (0.17 %). No other close hit in BOLD (best: 84 %). An investigation including sequences from more specimens would be necessary to investigate the separation between these two species. This brittle species has a peri Antarctic and eurybathic distribution. Distaplia cylindrica (Lesson, 1830) Holozoa cylindrica, Lesson, 1830: 439. Kott 1969: 29 and synonymy. Sanamyan & Schories 2003: 95 and synonymy. Tatian et al. 2005: 209. Stations (events when several trawling operations per station): 11 (424)- 14-54 A- 60. This very spectacular species in long cylinders reaches a very large size; a colony from station 14 is 108 cm long. One sequence for specimen A 3 DIS 98 (BOLD: ASCAN 014- 10). See D. colligans for more details. D. cylindrica is eurybathic, circumpolar, and also recorded from the Patagonian shelf. Sycozoa sigillinoides Lesson, 1830 Lesson 1830: 436. Millar 1960: 71 fig. 19 pl. 2 figs 3���8. Monniot & Monniot 1983: 37. Kott 2006: 188. Tatian 1998: 149. Stations: 1-3 - 13 A- 17. The CEAMARC colonies have short thick peduncles and very long cylindrical heads, the largest is 17 cm long on a 2 cm peduncle. The zooids open along the whole length of the colony and the common atrial aperture is terminal. There are no parastigmatic vessels crossing the stigmata. The stomach has a smooth wall. The gonads are poorly developed and no larvae have been found. Sequences for specimen A 3 SYC 38 (BOLD: ASCAN 018- 10) and specimen from lot A 3 SYC 39 (BOLD: ASCAN 019- 10) are identical. No close hit in BOLD (best: 78.3 %). The species has a very wide distribution both peri antarctic and Sub-Antarctic from 50 m and deeper to the bathyal zone., Published as part of Monniot, Fran��oise, Dettai, Agn��s, Eleaume, Marc, Cruaud, Corinne & Ameziane, Nadia, 2011, Antarctic Ascidians (Tunicata) of the French-Australian survey CEAMARC in Terre Ad��lie, pp. 1-54 in Zootaxa 2817 on pages 17-18, DOI: 10.5281/zenodo.277174, {"references":["Sluiter, C. P. (1932) Die von Dr. L. Kohl-Larsen gesammelten Ascidien von Sud-Georgien und der Stewart Insel. Senkenbergiana, 14, 1 - 19.","Millar, R. H. (1960) Ascidiacea. Discovery Reports, 30, 1 - 160.","Kott, P. (1969) Antarctic Ascidiacea. Antarctic Research Series, 13, 1 - 239.","Sanamyan, K. E. & Schories, D (2003) Ascidians from the Strait of Magellan. Aqua, Journal of Ichtyology and Aquatic Biology, 7 (3), 89 - 96.","Lesson, R. P. (1830) Zoologie. In: Duperrey, voyage autour du monde sur la corvette ' La coquille' 1822 - 1825. Volume 2 (1), Paris, Arthus-Bertrand, 256 - 279.","Tatian, M., Antacli, J. C. & Sahade, R. (2005) Ascidians (Tunicata, Ascidiacea): species distribution along the Scotia Arc. Scientia Marina, 69 (2), 205 - 214.","Monniot, C. & Monniot, F. (1983) Ascidies antarctiques et subantarctiques: Morphologie et Biogeographie. Memoires du Museum National d'Histoire Naturelle, Paris, 125, 1 - 168.","Kott, P. (2006) Observations on non-didemnid ascidians from Australian waters (1). Journal of Natural History, 40 (3 - 4), 169 - 234.","Tatian, M., Sahade, R. J., Doucet, M. E. & Esnal, G. I. (1998) Ascidians (Tunicata, Ascidiacea) of Potter Cove, South Shetland Islands, Antarctica. Antarctic Science, 10 (2) 147 - 152."]}

Distaplia arnbackae n. sp. (Figures 4, 6 F–H) Distaplia sp. Ärnbäck, 1929: 14. Distaplia occidentalis: Van Name, 1954: 8 (Not D. occidentalis Bancroft, 1899). Material examined: Chile, 4. region, Punta de Choros: Bajo tiburon, 15m, 1 colony; 17m, several fragments; Chile, 10. region, Caleta la Arena, 0 4 April 2009, several colonies (Holotype KBPIG 1399 / 1). Additional specimens: 10. region: Caleta la Arena, several colonies¸ Yaldad (Chiloe), 25 February 2007, mussel culture, several colonies. Description. Younger colonies consist of several small button shaped cormidiums some of which are well separated and some fused together (Figure 6 F); larger colonies are mostly solid encrusting sheets or cushions attached to substratum by the whole lower surface. In preservative they are rarely more than 5 mm thick and the largest collected colony is about 5 cm in extent. The test is free from encrusting or embedded sand and has soft spongy consistence characteristic for many Distaplia species. Zooids open on the upper surface only and are arranged into crowded circular or oval systems, each containing about 10 to 20 zooids with a cloacal opening in its centre. In younger colonies the systems are less crowded and are separated from each other by a shallow groove; smaller, button shaped colonies contain mostly a single system. The colour is very constant, all collected colonies as numerous seen on underwater photographs are always brilliant scarlet red, sometimes with sparse minute granules of white pigment especially between the systems, and often with white dot or a short white band on intersiphonal area of each zooid sometimes extending to the atrial languet. These markings may appear on photographs as small white splashes (Figure 6 G,H). The colour is not retained in preservative (formaline) for a long time, the preservative extracts red pigment, become purple-violet, and colonies fade to gray in about one year. Contracted zooids are no more than 3 mm long. Elongated branchial siphon has 6 small rounded lobes. Atrial aperture is a narrow transverse slit with short plain edged anterior languet; sometimes short atrial siphon is present (Figure 4 B). Crowded circular muscles form a sphincter around the branchial siphon and similar, but more spaced muscles are around trial aperture. About 15 fine spaced muscles are on the thorax. Some of them originate at the base of the branchial siphon, but most run obliquely from ventral side to the base of the thorax. Branchial sac has four rows of 15 or 16 long stigmata; each row is crossed by a parastigmatic vessel. Oesophageal neck is not especially long, being typically of the same length as the thorax. Obliquely oriented asymmetrical stomach has almost smooth wall, with faint and not always obvious internal plications. There are no apparent subdivisions of the intestine. A conspicuous elongated gastric reservoir lies in the gut loop and sometimes fills whole free space there. Gonads are on the right and below the pole of the gut loop. Male follicles form a loose rosette or a bunch with their ducts converging to the proximal end of the vas deferens in the centre of the bunch. One to three large ova are just below the gut loop. Several colonies contain numerous brood pooches with developing embryos and larvae which are mostly detached from zooids and freely lie in the tunic. Up to five larvae may present in each brood pouch. Larvae are elongated, with a trunk up to 1.1 mm long and a tail reaching a little more than halfway around it. An ocellus and an otolith are present. Adhesive organs are arranged triradially, two ventral ones have a single bulb at ventral side of the bases of their stalk, and a dorsal adhesive organ has two bulbs on the dorsal side of its stalk. Remarks. This species was described by Ärnbäck (1929) from Guaitecas Island, a location where it is rather common. A small colony examined by Ärnbäck's (1929) contained only immature zooids. Basing on the structure of zooid she pointed a close similarity of her material with Californian D. occidentalis but hesitated to identify Chilean specimens with that species referring to a large geographical distance between the records of these species. Van Name (1945) included Ärnbäck's record under the question to synonymy of D. occidentalis, and latter identified specimens from Chile with this species. He wrote: "In the present report I venture to assign the Chilean specimens to the North American species, as I am not able to mention any distinguishing characters." (Van Name, 1954: 9). Nevertheless, although zooids of Chilean species are similar to those of N. American D. occidentalis, the North and South American species appear to be distinct. Indeed, although several Distaplia species have distinctive zooids, in many others the zooids are virtually identical and in many cases features of a colony may be more important to delimitate species. Colonies of D. occidentalis may be "light green, variable, dark brown, cadmium-yellow, brick-red, dirty white" (Ritter & Forsyth, 1917: 465) while in D. arnbackae n. sp. colour is very constant and hardly shows even a slight tint variation, being always bright red. Chilean specimens examined by Van Name (1954: 9) were of the same colour ("red, redbrown or vine red"). Further, unlike D. arnbackae n. sp., which is always flat (with the exception of very small young colonies containing a single system), in D. occidentalis colonies are more or less mushroom shaped, with smaller area of attachment and expanded zooid-bearing top. Colonies of D. arnbackae n. sp. are distinctive and could not be confused with other colonial ascidians occurring in the region. The species is recorded in central Chile from Coquimbo and its range extends to the south to Guaitecas Islands. No other species of this genus are known from Chilean coasts north off Strait of Magellan. The colonies identified as D. colligans by Lagger et al. (2009) from Lilihuapi Island (42 °S) are certainly misidentified, they have much smaller larva than usually found in Distaplia and the colour photo (Lagger et al., 2009: Figure 2 F) shows colonies very similar to colonies of Diplosoma species which is abundand in neighboring waters (e.g. Chiloe Island, our unpublished data).

Sigillina pulvinus sp. nov. (figure 1C, plate 1A) Distribution. Type locality: Tasmania (Tasman Peninsula, Waterfall Bay outside Cathedral Cave in ledge in rock wall 10–13 m, coll. K. Gowlett Holmes, 21 October 94, syntypes SAM E2845). There are no further records. Description. Colonies are circular cushions with rounded margins, to 2 cm diameter. In life they are pinkish white with red zooids, their apertures showing at the surface and the zooids showing through the otherwise white, translucent test. Zooids, evenly spaced about 3 mm apart, are robust, 4–5 mm long (even when contracted). The abdomen and posterior abdominal stolon are about equal in length and the contracted thorax is shorter. Both apertures, on short cylindrical siphons each with six pronounced lobes around the opening, are anterior, on the upper surface of the colony. About 15 parallel muscle bands on each side of the thorax continue in a wide ventral band on the abdomen and the posterior abdominal stolon, surrounding the latter in longitudinal muscles. At each side of the distal extremity of the stout posterior abdominal extension, the muscles from each side are inserted into a small projecting horn from which the tips of the muscles project as sharp points. Three rows, each of about 16 long rectangular stigmata, are in the branchial sac. The descending limb of the gut loop consists of the oesophagus, an almost spherical, smooth stomach about half-way down the abdomen and a cylindrical duodenum and posterior stomach separated from each other and from the rectum by a short length of mid-intestine. The rectum is a long cylindrical tube occupying the whole ascending limb of the gut loop. Two large epicardial tubes, one each side of the ventral mid-line, extend through the abdomen and the one on the left projects down into the posterior abdominal vascular stolon. A single, large, yolky, spherical embryo, nearly 1.5 mm in diameter, with an ocellus, a small otolith and the tail wound all the way around the trunk, is in a brood pouch separated from the posterior end of the dorsal border of the thorax by a narrow constriction. These embryos are not sufficiently advanced to determine the form of other larval organs. Although embryos are in the brood pouch, gonads were not detected in these specimens. Remarks. The zooid is characteristic of this genus with a pronounced posterior abdominal stolon, three rows of stigmata, a brood pouch, a relatively short abdomen with a smooth spherical stomach half-way down it and parallel longitudinal thoracic muscles without conspicuous transverse ones. Despite the absence of gonads in the gut loop, the heart at the end of the abdomen and the smooth spherical stomach distinguish these specimens from Pseudodistoma (see Kott, 1992a). The circular colonies are more regular than the irregular ones of the South Australian S. fantasiana, which also is distinguished by the presence of more than one embryo developing in the less constricted brood pouch and without longitudinal muscles on the posterior abdominal stolon. The species most closely resembles the tropical S. signifera, but it has more regular colonies and smaller zooids. Like S. signifera, the species appears to be a member of the cyanea group of species (see Kott, 1992a) with a large posterior abdominal stolon with conspicuous muscles on it. Other Sigillina spp. have similar zooids, but different colonies., Published as part of KOTT, PATRICIA, 2003, New syntheses and new species in the Australian Ascidiacea, pp. 1611-1653 in Journal of Natural History 37 (13) on page 1618, DOI: 10.1080/00222930110104258, http://zenodo.org/record/5260089

Sigillina mjoebergi Harmeyer, 1919 Sigillina mjoebergi Hartmeyer, 1919: 117; Kott, 1990a: 96. Distribution. New records: Western Australia (Port Hedland, WAM 2.95; 791.88). This unusual species of problematical phylogeny is known only from the north-western Australian continental shelf., Published as part of KOTT, PATRICIA, 2003, New syntheses and new species in the Australian Ascidiacea, pp. 1611-1653 in Journal of Natural History 37 (13) on page 1619, DOI: 10.1080/00222930110104258, http://zenodo.org/record/5260089

Seventy‐eight species of Ascidiacea, including 21 new species from deeper waters (about 100 m and occasionally to about 500 m) off Western Australia appear to represent a diverse fauna not previously sampled. The relatively few solitary species taken include two possibly introduced (Styela plicata and S. clava). Large aplousobranch colonies dominate the collections. Aplousobranch species with numerous, small, deeply embedded zooids in massive three‐dimensional, vertical and often branched or stalked inflexible colonies supported by embedded sand (Polyclinindae) or calcareous spicules (Didemnidae) are common. Species with flexible stalks (enabling them to respond to prevailing currents) such as Clavelina meridionalis, Sigillina australis and S. cyanea were not taken often. Some known species (e.g. Synoicum chrysanthemum, and Atriolum tubiporum) previously considered rare were taken at these depths in significant numbers. Other unusual taxa (Pseudodiazona longigona and Condominium spp.) are recorded from ne...

Genus Hypsistozoa Brewin, 1953 Type species: Distaplia fasmeriana Michaelsen, 1924 Only two species are known. Both have stalked colonies with soft transparent test, although the outer layer of the stalk is often horny. As in other genera (Sycozoa and Distaplia) of the Holozoidae, zooids are arranged in well-organised, circular to elongate common cloacal systems, large sessile atrial openings have a pronounced anterior lip and expose a large part of the branchial sac directly to the regular circular or longitudinal cavities or canals, branchial sacs have four rows of long, narrow stigmata crossed by parastigmatic vessels, replicates are generated from the vegetative stolon at the posterior end of the zooid in a process involving the epicardial sac, fertilisation is in a brood pouch formed by a U-shaped loop of the oviduct that projects out from the postero-dorsal corner of the thorax and larval adhesive organs, each consisting of a terminal cone of adhesive cells in a shallow epidermal cup on a large bulbous stalk, are triradially arranged at the anterior end of the larval trunk. Kott’s (1990) report of muscle bands extending along the abdomen and the broad posterior abdominal vegetative stolon of the present genus is incorrect, muscles in the present genus as in all Holozoidae being confined to the thorax. However, the present genus is unique in the position of its gonads in the top of the posterior abdominal extension (rather than in the loop of the gut or in a sac attached to the zooid on the right side of the gut as in other genera of the Holozoidae). In the larvae, the S-shaped larval vegetative stolon, prolific larval budding, larval endodermal tubes and associated ectotrophic membranes are unique characteristics of Hypsistozoa (see Brewin (1956) and references therein). Brewin (1956) first documented the development of the embryo of the New Zealand Hypsistozoa fasmeriana (Michaelsen, 1924), describing its large stolon producing an unusually large number (up to 14) of blastozooids and the pair of straight endodermal tubes from the larval oesophageal endoderm to the upper surface of the larval ectoderm just behind the cerebral vesicle on each side of the dorsal mid-line (connecting the lumen of the larval oesophagus to the interior of the oviduct where it forms the brood pouch). A very thin ectotrophic membrane, circular in outline and lobed around its outer margins, is formed as an external flap from the ectoderm on each side of the external openings of the endodermal tubes. These membranes enclose the sides of the larval trunk outside the larval tunic. The deep rounded scallops around the outside of each ectotrophic membrane interdigitate with one another around the anterior and ventral margins of the larval trunk. The endodermal tubes and the flimsy bilateral ectotrophic membranes are of doubtful homology and appear to be unique in the Ascidiacea. Brewin (1956) proposed that the endodermal tubes provide a route for nutriment for the developing yolk-free larva. The evidence for this proposal is entirely circumstantial, viz. that such a source of nutriment would be needed through the five and a half months of larval development and the fact that the tubes open into the oesophagus. The provenance of the food that would pass down the oviduct into the brood pouch, and thence into the endodermal tubes is problematical, however, incurrent water (from which food has already been filtered by the mucous net before it passes through the pharyngeal wall) is not known to enter the oviduct. Nor is there an apparent role for the ectotrophic membranes that envelop the whole larva while it remains in the brood pouch. There is no evidence supporting Brewin’s suggested placenta-type role of diffusion of nutrients across the ectotrophic membranes as an important source of nutriment during the later stages of embryonic development. The absence of test over the ectotrophic membranes is offered in support of this role for the membranes but again the evidence is circumstantial and neither homologues nor even analogues of these structures have been identified in other organisms. In the absence of yolk, some of the needed energy for the developing embryo may come from the thick layers of follicle cells around the embryo rather than from the exogenous source that Brewin implied. On the basis of the position of their gonads, Kott (1990) assigned Australian specimens, formerly thought to be Distaplia distomoides (Herdman, 1899), to Hypsistozoa (Brewin, 1953). The newly recorded specimens of the Australian species resemble those of the New Zealand species and the single embryos in each long-stalked brood pouch confirm Kott’s (1990) assignation of the Australian species and establish that the larvae Brewin (1956 and 1959) described are characteristic of the genus Hypsistozoa., Published as part of Kott, Patricia, 2007, Taxonomic affinities of three stalked colonial species of the Ascidiacea (Tunicata) from the central coast of New South Wales and indications of a trans-Tasman connection, pp. 633-645 in Journal of Natural History 41 (9 - 12) on pages 636-638, DOI: 10.1080/00222930701248643, http://zenodo.org/record/5234077, {"references":["Brewin BI. 1953. Australian ascidians of the sub-family Holozoinae and a review of the sub-family. Transactions and Proceedings of the Royal Society of New Zealand 81 (1): 53 - 64.","Michaelsen W. 1924. Ascidiae Krikobranchiae von Neuseeland, den Chatham und den Auckland Inseln. Videnskabelige Meddelelser fra Dansk naturhistorisk Forening i Koebnhavn 77: 263 - 434.","Kott P. 1990. The Australian Ascidiacea Pt 2, Aplousobranchia (1). Memoirs of the Queensland Museum 29 (1): 1 - 266.","Brewin BI. 1956. The growth and development of a viviparous compound ascidian, Quarterly Journal of Microscopical Science, series 3, Hypsistozoa fasmeriana 97 (3): 435 - 454.","Herdman WA. 1899. Descriptive catalogue of the Tunicata in the Australian Museum. Australian Museum, Sydney, Catalogue 17: 1 - 139.","Brewin BI. 1959. An account of larval budding in the compound ascidian, Hypsistozoa fasmeriana. Quarterly Journal of Microscopical Science, series 3, 100 (4): 575 - 589."]}

Sigillina exigua sp. nov. (Figures 2A–C, 8D) Distribution Type locality. South Australia (Kangaroo I., ‘‘The Arches’’, Western River, on rock wall, 10–12 m, coll. K. Gowlett Holmes, 10 December 1999, syntypes SAM E3300). Description Colonies are small flat-topped cushions, about 2 cm diameter and to 5 mm high attached to calcareous debris. Zooids open on the upper surface. The test is soft and transparent. Zooids are short, about 3 mm long, the thorax, abdomen and posterior abdomen being each about equal in length. A short vascular stolon is at the posterior end of the body. Both six-lobed apertures are on the anterior end of the thorax. Three long rows of stigmata are in the branchial sac. Gonads are in the abdomen. A large almost spherical brood pouch constricted off from the postero-dorsal corner of the thorax contains a single embryo. The larval trunk is spherical and 1.1 mm diameter. An otolith and ocellus and three rows of stigmata are in the oozooid. Two large flat-topped adhesive organs, each in a thin-walled epidermal cup and with a short thick stalk, are depressed into the trunk in the anteromedian line. Three large median ectodermal ampullae alternate with the adhesive organs and curve around their stalks. The tail winds completely around the trunk. Remarks The cushion-like colonies and the zooids are particularly small for this genus. The species most closely resembles S. signifera, having flat-topped colonies and two large adhesive organs. However, both zooids and larvae of the present species are smaller (S. signifera larvae having a trunk 0.5 mm long). The present species from the southern Atlantic may be a sister species isolated from S. signifera which has a wide range and is common in tropical waters. The separately opening zooids, large larval trunks, wide, flat-topped, thick stalked larval adhesive organs, the three long rows of stigmata and the postero-dorsal thoracic brood pouch are characteristic of both this genus and Pseudodistoma, which is distinguished by its long posterior abdomen containing the gonads and the lack of the posterior abdominal vascular stolon of Sigillina. Kott (1992a) overlooked the similarity of Sigillina and Pseudodistoma and, although she later (Kott 1998, 2005b) emphasized the remarkable, large larval adhesive organs in Pseudodistoma, she again overlooked their likeness to the adhesive organs of Sigillina. It is possible the relationship of Sigillina to the Holozoidae based on the pattern of replication from the large vascular stolon (see Caullery 1909) could be less important than it previously was thought to be; and that the presence of the gonads in a posterior abdomen with conspicuous bands of longitudinal muscles along each side (that distinguishes Pseudodistomidae from Sigillina) may be less compelling than the characters (listed above) that are shared by these genera and suggest a closer phylogenetic relationship than previously was proposed., Published as part of Kott, Patricia, 2006, Observations on non-didemnid ascidians from Australian waters (1), pp. 169-234 in Journal of Natural History 40 (3 - 4) on pages 184-185, DOI: 10.1080/00222930600621601, http://zenodo.org/record/5232431, {"references":["Kott P. 1992 a. The Australian Ascidiacea, Pt 3 Aplousobranchia (2). Memoirs of the Queensland Museum 32: 377 - 620.","Kott P. 1998. Tunicata. In: Wells A, Houston WWK, editors. Zoological catalogue of Australia. Volume 34, Hemichordata, Tunicata, Cephalochordata. Melbourne: CSIRO Publishing. p 51 - 252, 259 - 261 (Appendices I - III), 265 - 292 (Index).","Kott P. 2005 b. Catalogue of Tunicata in Australian waters [CDROM]. Canberra: Australian Biological Resources Study. 301 p.","Caullery M. 1909. Recherches sur la famille des Distomidae. Bulletin Scientifique de la France et de la Belgique 42: 1 - 59."]}

Sycozoa sigillinoides Lesson, 1830 Sycozoa sigillinoides Lesson 1830, p 436. Kott 1990a, p 153 and synonymy. Distribution Previously recorded (see Kott 1990a): South Australia (S. Spencer Gulf); Tasmania (St Helen’s and Montague I.). Magellanic area; Falkland Is; Kerguelen, Heard I.; Macquarie I.; Chatham I.; New Zealand and the Antarctic. New records: Tasmania (Tasman Peninsula, 20–22 m, SAM E3247), Tasmanian Canyons (King I. Canyons, 249 m; Banks Strait, 168 m; Ling Hole, 163 m, 174 m; Pieman Canyon, 173–176 m). Description The newly recorded specimen from the Tasman Peninsula is a stiff, narrow stalk, with stiff annular thickenings at intervals. It has two short terminal branches, each bearing a small mushroom-shaped head with vertical double rows of zooids and a terminal common cloacal aperture. Remarks Australian records of this species are few, but the new records are from Tasmania within the range previously recorded. The newly recorded specimens (taken in April) are either long wiry headless stalks or stalks with very small (regenerating) heads. Millar (1960) reported headless stalks in May, June, and July; stalks with regenerating heads in December, March, May, June, and July; and sexual reproduction at its peak in March. The regenerating post-reproductive stalks of the newly recorded specimens (taken in April) are within this timeframe. The presence of isolated heads of this species in the plankton of the tropical Atlantic and Pacific (see Kott 1990a) has already been reported., Published as part of Kott, Patricia, 2006, Observations on non-didemnid ascidians from Australian waters (1), pp. 169-234 in Journal of Natural History 40 (3 - 4) on pages 188-189, DOI: 10.1080/00222930600621601, http://zenodo.org/record/5232431, {"references":["Lesson RP. 1830. Zoologie. In: Voyage autour du monde sur '' La Coquille '' pendant 1882 - 1825. Volume 2 (1) Paris: Arthus Bertrand. p 256 - 279, 433 - 440.","Kott P. 1990 a. The Australian Ascidiacea Pt 2, Aplousobranchia (1). Memoirs of the Queensland Museum 29: 1 - 266.","Millar RH. 1960. Ascidiacea. '' Discovery' ' Reports 30: 1 - 160."]}

Distaplia pallida Kott, 1990 (Figure 8H) Distaplia pallida Kott 1990a, p 121. Distribution Previously recorded (see Kott 1990a): South Australia (Great Australian Bight, Gulf St Vincent); Victoria (Portsea); New South Wales (Byron Bay); Tasmania (Tinderbox). New records: Tasmania (Port Davey, 5–7 m, SAM E3273). Description The colony is a firm, jelly-like translucent cushion with conical lobes protruding from the upper surface. Zooids are arranged in circular to long oval systems around sessile common cloacal openings. Sometimes the common cloacal apertures are long slits between two apparently parallel rows of zooids, and at each end the opening extends into narrow slits in the roof of the common cloacal canal that expose the atrial apertures directly to the exterior. The translucent internal or basal test contains criss-crossing posterior stolons of the zooids. About 12 stigmata are in each row in the branchial sac and the stomach has about 10 broad, parallel external folds. Gonads were not detected in the newly recorded specimens, although in previously recorded specimens they are reported to be in the gut loop. Photographs show colonies as pale blue, although they are beige in preservative. Remarks The species is distinguished from other species with circular to longitudinal systems by its relatively few branchial stigmata, broad stomach folds, and gonads in the gut loop (see Kott 1990a)., Published as part of Kott, Patricia, 2006, Observations on non-didemnid ascidians from Australian waters (1), pp. 169-234 in Journal of Natural History 40 (3 - 4) on pages 187-188, DOI: 10.1080/00222930600621601, http://zenodo.org/record/5232431, {"references":["Kott P. 1990 a. The Australian Ascidiacea Pt 2, Aplousobranchia (1). Memoirs of the Queensland Museum 29: 1 - 266."]}

Sycozoa cerebriformis (Quoy and Gaimard, 1834) (see Kott 1990a): Bass Strait, depth 50 m, Aquenal TAS 01085, QM G308808., Published as part of Kott, Patricia, 2006, Observations on non-didemnid ascidians from Australian waters (1), pp. 169-234 in Journal of Natural History 40 (3 - 4) on page 177, DOI: 10.1080/00222930600621601, http://zenodo.org/record/5232431, {"references":["Quoy J, Gaimard P. 1834. Mollusques. In: Voyages de decouvertes de l'Astrolabe 1826 - 29. Zoologie 3: 559 - 626.","Kott P. 1990 a. The Australian Ascidiacea Pt 2, Aplousobranchia (1). Memoirs of the Queensland Museum 29: 1 - 266."]}

Hypodistoma deerratum (Sluiter, 1895) (see Kott 2004): 14.715–17.605 ° S, 145.325– 146.355 ° E, depth 16–39 m., Published as part of Kott, Patricia, 2006, Observations on non-didemnid ascidians from Australian waters (1), pp. 169-234 in Journal of Natural History 40 (3 - 4) on page 177, DOI: 10.1080/00222930600621601, http://zenodo.org/record/5232431, {"references":["Sluiter CP. 1895. Tunicaten. In: Semon R. Zoologische Forschungsreisen in Australien und den Malagischen Archipel. Denkschriften der Medizinisch-Naturwissenschaftlichen Gesellschaft zu Jena 8: 163 - 186; Nachtrag zu den Tunicaten 325 - 326.","Kott P. 2004. Ascidiacea (Tunicata) in 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, Patricia (2006): Observations on non-didemnid ascidians from Australian waters (1). Journal of Natural History 40 (3-4): 169-234, DOI: 10.1080/00222930600621601, URL: http://dx.doi.org/10.1080/00222930600621601

Distaplia australiensis Brewin, 1953 (Figure 8E, F) Distaplia australiensis Brewin 1953, p 61. Kott 2003, p 1619 and synonymy (part, not specimens from Queensland = Distaplia turboensis Kott 2004, p 45). Distribution Previously recorded (see Kott 2003 and D. turboensis Kott, 2004): South Australia (Spencer Gulf, Gulf St Vincent, Bass Strait, D’Entrecasteaux Channel, Huon Channel. New records: South Australia (Kangaroo I., 4–7 m, SAM E3294–5). Description Long cylindrical stalks each with a soft, rounded head surrounded by parallel double rows of zooids extending from the top of the stalk to a terminal common cloacal aperture. Zooids have the usual large atrial aperture opening directly into the vertical common cloacal canal between each row of zooids of the pair. The stomach wall has about 16 parallel longitudinal pleats. Gonads were not detected in the newly recorded colonies, although usually they are in a sac separated from the abdomen by a narrow constriction. Remarks Although the arrangement of the zooids in long vertical rows and the presence of the gonads in a posterior abdomen is similar to the tropical Distaplia turboensis, the present species is distinguished by its long cylindrical stalks and fewer stomach folds., Published as part of Kott, Patricia, 2006, Observations on non-didemnid ascidians from Australian waters (1), pp. 169-234 in Journal of Natural History 40 (3 - 4) on page 186, DOI: 10.1080/00222930600621601, http://zenodo.org/record/5232431, {"references":["Brewin BI. 1953. Australian ascidians of the sub-family Holozoinae and a review of the sub-family. Transactions and Proceedings of the Royal Society of New Zealand 81: 53 - 64.","Kott P. 2003. New syntheses and new species in the Australian Ascidiacea. Journal of Natural History 37: 1611 - 1653.","Kott P. 2004. Ascidiacea (Tunicata) in Australian waters of the Timor and Arafura Seas. The Beagle, Records of the Museums and Art Galleries of the Northern Territory 20: 37 - 81."]}

Distaplia florida Kott, 1990 (Figure 8G) Distaplia florida Kott 1990a, p 118. Distribution Previously recorded (see Kott 1990a): South Australia (Great Australian Bight); Victoria (King I.); New South Wales (Byron Bay). New records: Victoria (Flinders Pier, QM G308566); Tasmania (Tasman Peninsula, 15–18 m, SAM E3293; Port Davey, 6–8 m, SAM E3233). Description Colonies are soft, hemispherical or cushion-shaped (up to 3 cm diameter) to flat encrusting sheets with circular to elongate systems of zooids around large circular common cloacal apertures, about 5 mm apart. They are beige in preservative, and minute crystalline particles in the test give it a cloudy appearance. In the preserved specimens, radial furrows around the common cloacal apertures may be the result of preservation and/or contraction. A shallow concavity in the surface over each circular common cloacal cavity has its margin overhung by the surrounding surface test. Branchial apertures open beneath this overhang. The atrial apertures are large sessile openings around the common cloacal cavity with their anterior lips extending out into the margin of the common cloacal aperture. Black faecal pellets in the base of the circular common cloacal cavities are conspicuous from the surface. About 10 zooids surround each common cloacal cavity. Zooids have a long oesophageal neck, a smooth stomach wall and gonads in the gut loop. Four rows of about 25 stigmata are each crossed by a parastigmatic vessel. A vegetative stolon projects into the base of the colony. Remarks Species of Distaplia are difficult to distinguish from one another, often having circular systems and soft cloudy test like the present one. The presence or absence of a posterior abdomen is a useful character but, when zooids are immature as in the present case, the smooth stomach wall helps to distinguish this species from others in which it is folded. The concavities over each common cloacal cavity in the preserved specimens appear to be characteristic of this species, although both species have circular systems, smooth stomachs and gonads in the gut loop. The present species is distinguished from Distaplia viridis Kott, 1957 by the more numerous branchial stigmata, and by its colour., Published as part of Kott, Patricia, 2006, Observations on non-didemnid ascidians from Australian waters (1), pp. 169-234 in Journal of Natural History 40 (3 - 4) on pages 186-187, DOI: 10.1080/00222930600621601, http://zenodo.org/record/5232431, {"references":["Kott P. 1990 a. The Australian Ascidiacea Pt 2, Aplousobranchia (1). Memoirs of the Queensland Museum 29: 1 - 266.","Kott P. 1957. Ascidians of Australia II. Aplousobranchiata Lahille: Clavelinidae Forbes and Hanley and Polyclinidae Verrill. Australian Journal of Marine and Freshwater Research 8: 64 - 110."]}