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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.

Pharyngodictyon melanesius sp. nov. Figure 2 Etymology: from Melanesia Stations: SPANBIOS: DW 5227: 1 specimen. DW 5228: 2 specimens designated as syntypes (MNHN IT-2018- 77 Paris, France). The colonies are composed of a spherical head above a long thin peduncle (Fig. 2A). The tunic is soft, translucent, without sand. The heads are 4 to 5mm in diameter; the longest peduncle is 30mm. The thoraces and abdomens are included in the head and the post-abdomens with gonads extend into the peduncle. The body wall has muscular fibres in a sphincter at the siphons and a few longitudinal fibres on the thorax. On one zooid two lips can be seen on each aperture. The oral tentacles are thin and numerous but could not be counted. The dorsal tubercle is button-like. The triangular dorsal languets are erect between seven to nine transverse branchial bars (Fig. 2B,C). The digestive loop forms a right angle with the thorax. The stomach is short and its wall could not be clearly seen. The post-abdomen extends the entire length of the peduncle with the gonads in a long mass in the anterior part. One larva 0.8mm in diameter was found in the colony head (Fig. 2D). Two sensitive organs are present as black spots. There are three adhesive papillae in a line each separated by a median protrusion with four round papillae on each larval side (Fig. 2D). This larva obviously differs from those of other Pharyngodictyon species recorded from the New Caledonian area: P. magnifili has similar colonies and zooids but a different larva. P. bisinus Monniot C. & Monniot F., 1991 has club-shaped sandy colonies but zooids with only two transverse branchial bars. P. cauliformis MonniotC. & Monniot F., 1991 differs by its large sandy ramified colony on a stout peduncle and a larva of three adhesive papillae circled by a ring of digitate vesicles. P. elongatum Millar, 1982 from New Zealand with club-shaped colonies has a naked tunic and the branchial tissue has three transverse bars. P. mirabile Herdman, 1886 from the Antarctic Ocean is bare, club-shaped with five transverse branchial bars according to Millar (1982) who examined the type and Monniot C. & Monniot F. (1985). P. reductum Sluiter, 1906 represents a sessile unique specimen collected on a beach which likely does not belong to the genus Pharyngodictyon., Published as part of Exbodi, Françoise Monniot, 2022, Additional records of bathyal ascidians (Tunicata) from the New Caledonia region, pp. 201-223 in Zootaxa 5195 (3) on pages 204-205, DOI: 10.11646/zootaxa.5195.3.1, http://zenodo.org/record/7187776, {"references":["Millar, R. H. (1982) The marine fauna of New Zealand: Ascidiacea. Memoirs of the New Zealand Oceanographic Institute, 85, 1 - 117","Herdman, W. A. (1886) Report on the Tunicata collected during the voyage of H. M. S. Challenger during the years 1873 - 1876; part II; Ascidiae compositae. Report of the Voyage Challenger, 14, 1 - 429.","Sluiter, C. P. (1906) Tuniciers in: Expedition Antarctique Francaise (1903 - 1905) commandee par le Dr. Charcot. Masson & Cie, Paris, 150 pp."]}

Pharyngodictyon magnifili Monniot C. & Monniot F., 1991 Figure 1 Stations: SPANBIOS: CP 5217: 4 specimens. CP 5237: 1 specimen. The largest specimen has a spherical head 15mm in diameter on a narrow peduncle 20mm long (Fig. 1A). The tunic is vitreous with some encrusted sand. The apertures cannot be seen, and all zooids are contracted. Thoraces and abdomens are located in the head and the long post-abdomens extend inside the peduncle. The oral tentacles are thin, long, protruding out of the siphon (Fig. 1B). The branchial tissue has at least seven transverse bars with triangular dorsal languets. The stomach is elongated with longitudinal folds (Fig. 1B). The ovary is anterior to a clump of testis lobes. In one zooid two immature embryos are incubated in the thoracic cavity (Fig. 1B). One tadpole (Fig. 1C) was found free inside the colony head. It has three adhesive papillae in a line circled by very numerous ramified vesicles (Fig. 1C). Sensitive organs cannot be clearly seen. All characters of the SPANBIOS specimens well correspond to those already described from New Caledonia and figured in Monniot C. & Monniot F. 1991 (Figs 7F; 10)., Published as part of Exbodi, Françoise Monniot, 2022, Additional records of bathyal ascidians (Tunicata) from the New Caledonia region, pp. 201-223 in Zootaxa 5195 (3) on pages 203-204, DOI: 10.11646/zootaxa.5195.3.1, http://zenodo.org/record/7187776

Exbodi, Françoise Monniot (2022): Additional records of bathyal ascidians (Tunicata) from the New Caledonia region. Zootaxa 5195 (3): 201-223, DOI: https://doi.org/10.11646/zootaxa.5195.3.1

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.

Allorecognition, the ability to distinguish self or kin from unrelated conspecifics, plays several important biological roles in invertebrate animals. Two of these roles include negotiating limited benthic space for colonial invertebrates, and inbreeding avoidance through self-incompatibility systems. Subphylum Tunicata (Phylum Chordata), the sister group to the vertebrates, is a promising group in which to study allorecognition. Coloniality has evolved many times independently in the tunicates, and the best known invertebrate self-incompatibility systems are in tunicates. Recent phylogenomic studies have coalesced around a phylogeny of the Tunicata as well as the Order Stolidobranchia within the Tunicata, providing a path forward for the study of allorecognition in this group.

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.

This paper presents the ascidians from the Family Polyclinidae collected in the Gulf of Mexico during the Hourglass Cruises between August 1965 and November 1967. The analysis of the collected material revealed the presence of eight polyclinid ascidians from three different genera, with two new species and two new records for the Gulf of Mexico.

Aplidium benhami (Brewin, 1946) (Figure 6d) Aplidium (Amaroucium) benhami Brewin, 1946: 95–97, fig. 4, pl. 2, figs 1, 4, pl. 3, fig. 3, pl. 5, fig. 1. Amaroucium benhami Brewin, 1956: 122; 1958a: 439; 1960: 119. Material examined New records. NEW ZEALAND, Bluff Harbour, Tiwai Point (46°35.52 ʹ S, 168°21.14 ʹ E, wharf pile, coll. M. Page, 9 m, 20 August 2007, NIWA68101); Tiwai Point (46°35.51 ʹ S, 168° 21.15 ʹ E), wharf pile, coll. L. Peacock, 6 m, 10 February 2011, NIWA84207. Previously recorded. New Zealand, South Island; Portobello Peninsula (Brewin 1946); Chatham Islands (Brewin 1956); Stewart Island (Brewin 1958a); Cook Strait (Brewin 1960); Fiordland (Page et al. 2014). Description Colonies of Aplidium benhami collected off wharf piles in Bluff Harbour are relatively large, compared to specimens sampled from natural substrata in more exposed environments. They are bright orange (5YR12), cushion-shaped, firm gelatinous colonies measuring up to 100 mm in greatest diameter. The branchial apertures of the zooids are pigmented white, standing out against bright orange thoraces, and a lightly pigmented orange test (Figure 6d). Unlike the small colonies from other regions, the zooids are arranged in parallel rather than stellate systems, and common cloacal apertures are not obvious. The zooids are stout, measuring 7 mm total length, with a thorax and abdomen of approximately equal length and a post-abdomen 3 mm long. The branchial aperture has low indistinct lobes, and the small atrial aperture is surmounted by 3 short atrial lappets. Three embryos are sequentially developed in the atrial brood pouch. The larval characters are as described in Page et al. (2014). Also noted in the present specimen is the orange pigmentation of the branchial sac. Remarks The Tiwai Point A. benhami colonies closely resemble the Otago Harbour holotype in colour and zooid morphology (Brewin 1946). Furthermore, larval characters are the same for this species as described from Fiordland (Page et al. 2014)., Published as part of Page, M. J., 2018, Colonial ascidians from the Foveaux Strait region of New Zealand, pp. 1157-1180 in Journal of Natural History (J. Nat. Hist.) (J. Nat. Hist.) 52 (17 - 20) on pages 1171-1172, DOI: 10.1080/00222933.2018.1450903, http://zenodo.org/record/5174607, {"references":["Brewin BI. 1946. Ascidians in the vicinity of the Portobello Marine Biological Station, Otago Harbour. Trans Proc N Z Inst. 76: 87 - 131.","Brewin BI. 1956. Ascidians from the Chatham Islands and the Chatham Rise. Trans Proc Roy Soc N Z. 84: 121 - 137.","Brewin BI. 1958 a. Ascidians of New Zealand. Part XI. Ascidians of the Stewart Island region. Trans Roy Soc N Z. 85: 439 - 453.","Brewin BI. 1960. Ascidians of New Zealand. Part XIII. Ascidians of the Cook Strait region. Trans Proc Roy Soc N Z. 88: 119 - 120.","Page M, Willis T, Handley S. 2014. The colonial ascidian fauna of Fiordland, New Zealand with a description of two new species. J Nat Hist. 48: 1653 - 1688."]}

Polyclinum novaezelandiae Brewin, 1958a (Figures 6b, 7a–c) Polyclinum novaezelandiae Brewin, 1958a: 442; Millar 1982: 43. Material examined New records. NEW ZEALAND, Bluff Harbour, Tiwai Point (46.591°S, 168.349°E, 10 m, 31 August 2007, NIWA68097, 1 colony; 46.591°S, 168.349°E, 6 m and 7 February 2011, NIWA87159, 2 colonies). Previously recorded. New Zealand, Foveaux Strait (Brewin 1958a). Description Colonies of this species are large hemispherical cushions reaching 100 mm in greatest diameter and 50 mm high, attached to the substratum by most of their base. Numerous relatively tall (3 mm long), cone-shaped common cloacal apertures are irregularly spaced among crowded zooid branchial apertures, showing no apparent arrangement into regular systems (Figure 6b). The outer test is sparsely covered with fine sand and the colonies have a sky-blue test (5BG8/2), which is apparent on the rims on the branchial apertures. Internally, the test is transparent and gelatinous, containing few sand grains. Large zooids are crowded in the test. The thorax is 4 mm long and has a short branchial aperture with 6 low, well-defined lobes. The atrial aperture is small, muscular and separate from the long atrial languet (Figure 7a). Thirteen longitudinal muscles run on each side from the branchial aperture to the dorsal side of the body wall. The branchial sac has 17–19 rows of 16–18 stigmata per half-row. Ten papillae were counted on each transverse vessel (Figure 7b). The abdomen is short (2 mm long),and the gut is twisted to the left forming a horizontal loop posterior to the throax. A bilobate anus opens in the peribranchial cavity adjacent to the sixth row of stigmata. A relatively long pyriform post-abdomen (6 mm long) contains up to 25 testis follicles posterior to several developing ova (Figure 7c). No larvae were present in colonies examined in this study. Remarks The colony and zooid morphology of specimens collected from Bluff agree closely with the type species from Foveaux Strait described by Brewin (1958a). The in-situ image of the colony (Figure 6B) shows large, scattered common cloacal apertures with raised rims, which collapse on removal from water and are not evident in preserved specimens. The zooids of Polyclinum novaezelandiae are distinguished from 3 other species of Polyclinum endemic to New Zealand – P. sluiteri Brewin, 1956, P. michaelseni Brewin, 1956 and P. cerebrale Michaelsen, 1924 – by a greater number of rows of stigmata in the branchial sac. Furthermore, the colonies of the former 2 species are stalked, while those of P. cerebrale are cushion-shaped with a network of conspicuous sinuous ridges (Millar 1982), unlike the morphology of P. novaezelandiae specimens collected from Bluff., Published as part of Page, M. J., 2018, Colonial ascidians from the Foveaux Strait region of New Zealand, pp. 1157-1180 in Journal of Natural History (J. Nat. Hist.) (J. Nat. Hist.) 52 (17 - 20) on page 1170, DOI: 10.1080/00222933.2018.1450903, http://zenodo.org/record/5174607, {"references":["Brewin BI. 1958 a. Ascidians of New Zealand. Part XI. Ascidians of the Stewart Island region. Trans Roy Soc N Z. 85: 439 - 453.","Millar RH. 1982. The marine fauna of New Zealand: Ascidiacea. New Zealand Oceanographic Memoir. 85: 114.","Brewin BI. 1956. Ascidians from the Chatham Islands and the Chatham Rise. Trans Proc Roy Soc N Z. 84: 121 - 137.","Michaelsen W. 1924. Ascidiae Krikobranchiae von Nueseeland den Chatham- und den Auckland- Inseln. Videnskabelige Meddelelser fra Dansk naturhistorisk Forening i KObenhavn. 77: 263 - 434."]}

Synoicum stewartense (Michaelsen, 1924) (Figure 6c) Macroclinum stewartense Michaelsen, 1924: 413–421, figs 26, 27, 28. Synoicum stewartense: Millar, 1982: 15, fig. 3. Material examined New records. NEW ZEALAND, Stewart Island, Bob’ s Point (41° 51.25 ʹ S, 168° 07.57 ʹ E, 15 m, 31 August 2007, NIWA68089). Previously recorded. Stewart Island, 35 fathoms Michaelsen 1924); in dredged material off Stewart Island (Brewin 1958a); Chatham Rise (Millar 1982); Fiordland (Page et al. 2014). Description Closely spaced, flat-topped, sand-encrusted heads 10–15 mm in diameter, each with 15–18 zooids arranged in a circle around a central, raised common cloacal aperture (Figure 6c). Zooids are large and pigmented red, with internal structures as described in Page et al. (2014). Remarks The central, raised common cloacal aperture, depressed branchial apertures of zooids in a circular system and a low raised rim around the anterior of each colony lobe are consistent with characters for this species described by Michaelsen (1924) and Millar (1982). Adherent sand covers the purple zooids., Published as part of Page, M. J., 2018, Colonial ascidians from the Foveaux Strait region of New Zealand, pp. 1157-1180 in Journal of Natural History (J. Nat. Hist.) (J. Nat. Hist.) 52 (17 - 20) on page 1171, DOI: 10.1080/00222933.2018.1450903, http://zenodo.org/record/5174607, {"references":["Michaelsen W. 1924. Ascidiae Krikobranchiae von Nueseeland den Chatham- und den Auckland- Inseln. Videnskabelige Meddelelser fra Dansk naturhistorisk Forening i KObenhavn. 77: 263 - 434.","Millar RH. 1982. The marine fauna of New Zealand: Ascidiacea. New Zealand Oceanographic Memoir. 85: 114.","Brewin BI. 1958 a. Ascidians of New Zealand. Part XI. Ascidians of the Stewart Island region. Trans Roy Soc N Z. 85: 439 - 453.","Page M, Willis T, Handley S. 2014. The colonial ascidian fauna of Fiordland, New Zealand with a description of two new species. J Nat Hist. 48: 1653 - 1688."]}

Pseudodistoma cereum Michaelsen, 1924 (Figure 9b) Pseudodistoma cereum Michaelsen, 1924: 364–374, fig. 17. Brewin, 1958a: 444–445, fig. 1C 1, C 2, C 3, C 4. Kott, 1963: 77; 1972a: 12–13; 1972b: 173., Published as part of Page, M. J., 2018, Colonial ascidians from the Foveaux Strait region of New Zealand, pp. 1157-1180 in Journal of Natural History (J. Nat. Hist.) (J. Nat. Hist.) 52 (17 - 20) on page 1176, DOI: 10.1080/00222933.2018.1450903, http://zenodo.org/record/5174607, {"references":["Michaelsen W. 1924. Ascidiae Krikobranchiae von Nueseeland den Chatham- und den Auckland- Inseln. Videnskabelige Meddelelser fra Dansk naturhistorisk Forening i KObenhavn. 77: 263 - 434.","Brewin BI. 1958 a. Ascidians of New Zealand. Part XI. Ascidians of the Stewart Island region. Trans Roy Soc N Z. 85: 439 - 453.","Kott P. 1963. The ascidians of Australia. IV. Aplousobranchiata Lahille: Polyclinidae Verril (continued). Aust J Marine Freshwater Res. 14: 70 - 118.","Kott P. 1972 a. The ascidians of South Australia I. Spencer Gulf, St. Vincent Gulf and Encounter Bay. Trans Roy Soc South Aust. 96: 1 - 52.","Kott P. 1972 b. The ascidians of South Australia II. Eastern sector of the Great Australian Bight and Investigator Strait. Trans Proc N Z Inst. 96: 165 - 196."]}

Page, M. J. (2018): Colonial ascidians from the Foveaux Strait region of New Zealand. Journal of Natural History (J. Nat. Hist.) 52 (17-20): 1157-1180, DOI: 10.1080/00222933.2018.1450903, URL: http://dx.doi.org/10.1080/00222933.2018.1450903

Aplidium knoxi (Brewin, 1956) (Figures 6e, 8a–c) Amaroucium knoxi Brewin, 1956: 125–127, fig. 2D 1, D 2. Material examined New records. NEW ZEALAND, Bluff Harbour, Tiwai Point, wharf piles (46.591°S, 168.349°E, 9 m, 21 August 2007, NIWA68091; 46.591°S, 168.349°E, 5 m, 8 November 2012, NIWA68167). Previously recorded. New Zealand, Chatham Islands (Brewin 1956). Description The pink (5R6/10) colony of Aplidium knoxi is approximately 150 mm long, 50 mm wide and 30 mm thick. Common cloacal apertures with thin transparent rims raised 2 mm above the surface occur randomly throughout the colony (Figure 6e). Zooids are evenly distributed throughout the colony with no apparent arrangement in systems. The test is soft, gelatinous and invested with numerous test and granular cells, with some incorporated sediment. The zooids are relatively large and robust, the thorax measures 1.3 mm and abdomen 2.2 mm. The thorax has approximately 12 longitudinal muscles, a branchial aperture with 6 low rounded lobes, and a narrow atrial aperture surmounted by a tripartite lappet (Figure 8a). There are 14 rows of approximately 10 stigmata per half-row in the branchial sac. The barrel-shaped stomach has 24 folds, some of which are discontinuous. There is a wide intestinal tract ending in a bilobate anus. The post-abdomen is long (6.4 mm) with fine muscles evenly spaced along the entire length. Numerous testis follicles are in 2 irregular rows occupying the posterior half of the post-abdomen with developing ova anterior to the testis follicles (Figure 8b). A large convoluted vas deferens runs ¾ of the length of the post-abdomen. Larvae were present in zooids from a colony collected in late spring 2012 (NIWA68167). They have a robust 1.5 mm long trunk with 3 adhesive organs and 3 stout median ampullae. The anterior end of the trunk is covered by an arc of epidermal vesicles each side of the midline (Figure 8c). Remarks The colony size and colour, and arrangement of zooids, are different from the holotype collected off coastal rocks in the Chatham Islands by Brewin (1956). The morphology of the zooids is, however, the same as in our specimen. The number of folds of the stomach and rows of stigmata are similar, and both have a tripartite atrial languet, bilobate anus and numerous testis follicles in the lower part of the posterior abdomen, posterior to the ovary. Larvae of this species are newly described here. The variation in colony size and arrangement of zooids is most likely to be a function of exposure to high currents. A similar environmental response is common for Pseudodistoma cereum in Fiordland, where encrusting colonies are found in exposed habitats and massive forms are in deep water (Page et al. 2014)., Published as part of Page, M. J., 2018, Colonial ascidians from the Foveaux Strait region of New Zealand, pp. 1157-1180 in Journal of Natural History (J. Nat. Hist.) (J. Nat. Hist.) 52 (17 - 20) on pages 1172-1173, DOI: 10.1080/00222933.2018.1450903, http://zenodo.org/record/5174607, {"references":["Brewin BI. 1956. Ascidians from the Chatham Islands and the Chatham Rise. Trans Proc Roy Soc N Z. 84: 121 - 137.","Page M, Willis T, Handley S. 2014. The colonial ascidian fauna of Fiordland, New Zealand with a description of two new species. J Nat Hist. 48: 1653 - 1688."]}

Colonial ascidians, Clavelina elegans (Oka, 1927) and Clavelina miniata Watanabe & Tokioka, 1973 are reported for the first time in Korean waters. As a result of this study, three species of the genus Clavelina are now recorded in Korean fauna. Clavelina elegans and C. miniata have been reported only from Japan. We expanded the distribution range of these species to Korea. The specimens of C. elegans and C. miniata were collected from the subtidal zone of Beomseom and Chagwido in Jeju-do by SCUBA diving. Detailed descriptions, illustrations and photographs of these species are provided in this paper.

Photosymbiotic ascidian fauna were surveyed in the subtidal zone off Pari Island in the Thousand Islands (Java Sea, Indonesia). Nine species were recorded: Didemnum molle, Trididemnum miniatum, Lissoclinum patella, L. punctatum, L. timorense, Diplosoma gumavirens, D. simile, D. simileguwa, and D. virens. All of these species have been previously recorded in the Ryukyu Archipelago, Japan. Diplosoma gumavirens and D. simileguwa were originally described from the Ryukyu Archipelago in 2009 and 2005, respectively, and all of the observed species are potentially widely distributed in Indo-West Pacific coral reefs.

A colonial ascidian, Synoicum clavatum has previously been reported from Japan. Here, we provide detailed descriptions and illustrations of S. clavatum as the first record in Korea. Synoicum clavatum is characterized by club­ shaped colonies with oval head and elongate stalk, circular cloacal systems, a branchial sac with 14-16 stigmata rows of 10-17 stigmata per row and a stomach with smooth surface. The specimens of S. clavatum were collected in the subtidal zone (15-25 m depth) at Beomseom and Mumseom in Jeju­do while SCUBA diving from 2000 to 2014.

Colonial animals are often lacking in taxonomic characters due to their small size and the simple morphology of zooids. Since zooid size is nearly uniform in many colonial ascidians, the stigma numbers in each row can be a useful taxonomic character. To evaluate their potential utility, we investigated intraspecific variations in stigma patterns in a subset of photosymbiotic didemnid ascidians, including five morphotypes of Didemnum molle , Lissoclinum midui , Trididemnum clinides , and T. nubilum . Stigma number patterns were almost stable in L. midui and T. nubilum . In contrast, there was considerable variation in stigma number even among clone zooids within the same colony in D. molle and T. clinides . Further, the stigma patterns did not differentiate the five morphotypes of D. molle . There was no significant correlation between the total number of stigma and the length of the thorax in any of the species examined here, suggesting that stigma number is probably invariable within each zooid. Stigma patterns can be usable as a taxonomic character in didemnid ascidians, particularly in species having one or a few patterns. Even in species with various patterns, the range of variation will be informative once such ranges are comprehensively described for didemnid species.

The specimens of Enterocola sydnii Chatton & Harant, 1924, as studied for this paper, were found in the following compound ascidians (Aplousobranchia: Polyclinidae) collected by the author at Roscoff in 1992: females and males in Aplidium argus (Milne Edwards 1841); females and males in A. nordmanni (Milne Edwards 1841); and females in A. turbinatum (Savigny 1816). The female E. sydnii is fully redescribed, based mainly on specimens in A. argus. The male E. sydnii is described for the first time, primarily from specimens in A. nordmanni. In living females, the color of the ovarian eggs in the metasome is a pale rose.

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.

The mysterious morphological structure of ascidians was taken into account for classification by various researchers. Herdman (1882) has given a classification of tunicate based upon the external features in relation to gemmation and formation of colonies. Originally the suborders are designated as the orders Aplousobranchia, Phlebobranchia and Stolidobranchia (Lahille 1886) based upon the complexity of the branchial sac.

During the Spanish expedition CIEMAR 99/00, on board the BIO‐Hesperides, 30 species of ascidians (distributed in 13 genera and eight families) were collected using a rock dredge in the Bransfield and Gerlache straits. Most of them were already known, but one species, Tetrazona ciemari sp. nov., is new for science. Additional morphological data are provided for six species. Five are reported for only the second time and the known distributions of five species are extended.

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.

Trididemnum shawi sp. nov. (Figures 12, 11D) Type material Holotype: NIWA 10872. Type locality: Fiordland, Crayfish Heights, Thompson Sound (45° 14.279’S, 166° 59.566’E, 10 m, 31 February 2006). Paratypes: Fiordland, Crayfish Heights, Thompson Sound (45° 14.279’S, 166° 59.566’E, 10 m, 31 February 2006, NIWA 87166); The Narrows, Long Sound (46° 03.829’S, 166° 44.16’E, 13 m, 28 February 2009 NIWA 49945, one colony); Nine Fathom Passage, Dusky Sound (45° 44.237’S, 166° 53.199’E, 16 m, 1 February 2009, NIWA 49960, one colony); Sunday Cove, Breaksea Sound (45° 35.89S, 166° 44.58’E, 10 m, 18 April 2012, NIWA 68138, 68139, 68140, 68141 and 68142). Etymology Named after Lance Shaw in recognition of his lifetime passion for conservation in Fiordland. Description The colonies of Trididemnum shawi sp. nov. are irregular shaped cushions reaching 150 mm long and 50 mm high. They have large terminal common cloacal apertures (5 mm diameter) located at the proximal end of upright lobes in the colony. The colony is supported by positive hydrostatic pressure and basal test core expanded into the centre of large common cloacal cavities that collapse on removal from water. Colonies are peach coloured (YR 7/8) with characteristic clusters of red pigment cells scattered randomly throughout the test (Figure 11D). The texture is gelatinous with zooids regularly packed around the outside edge and sparse spicules concentrated in a layer around zooid branchial apertures. The inner test below the zooid thoraces has no spicules. Developing larvae are present in the test surrounding posterior abdominal cavities in colonies from Breaksea Sound. The zooids are small, the thoraces measuring 0.45 mm and abdomen 0.8 mm long in contracted specimens. There are reticulated posterior abdominal canals running below a single layer of zooids. The canals connect to a central common cloacal cavity in the anterior half of the colony, the centre supported by an extension of the basal test. The zooid branchial aperture has six sharply pointed lobes, and the atrial aperture is a sessile opening in the centre of the thorax. The branchial sac has three rows of stigmata and a small lateral thoracic organ each side adjacent to the third row of stigmata (Figure 12A). The number and shape of stigmata are difficult to determine due to contraction of the thorax. There is a long retractor muscle originating from the base of the thorax. The gut has a smooth globular stomach and the intestine is wide with constrictions occurring between duodenum, posterior stomach and rectum (Figure 12A). There is a single large dome-shaped testis follicle with a vas deferens tightly coiled 10–11 times anticlockwise (Figure 12B); a large ovum lies on the anterior dorsal side of the testis. Developed larvae in colonies collected in April 2012 from Breaksea Sound (NIWA68138) are large (trunk length 1.1 mm) and have four stout lateral ampullae crowded each side of three slender adhesive papillae (Figure 12C). Zooids in these colonies have no testis, suggesting that the reproductive season has ended, but the brooded larvae are still maturing. Stellate spicules are present in a layer around the zooid thoraces and range in size from Remarks Of nine species of Trididemnum described with sessile atrial openings similar to Trididemnum shawi sp. nov., Trididemnum cyclops Michaelsen, 1921 and T. miniatum Kott, 1977 have only six, and T. nubilum Kott, 1980 seven coils of the vas deferens, compared with 10–11 for T. shawi sp. nov.. Trididemnum paracyclops Kott, 1980 from Australia and the Western Pacific has 10 coils of the vas deferens, but differs markedly in colony (forming thin encrusting colonies), zooid and spicule morphology, a zooid with a long oesophageal neck and larvae with only two adhesive papillae. Trididemnum poma Monniot and Monniot, 2001 from Saipan has a larva with a similar arrangement of adhesive papillae and lateral ampullae, but the larvae are significantly smaller (0.25 mm compared with 1.1 mm) than those of T. shawi sp. nov.. Furthermore, the colonies of T. poma are thin, brittle and encrusting compared with those of T. shawi. Both Trididemnum species recorded from New Zealand, T. sluiteri Brewin, 1958 and T. cerebriforme Hartmeyer, 1913, differ from T. shawi in possessing atrial siphons. Trididemnum shawi sp. nov. is distinguished from the majority of species in this genus by the presence of a sessile transverse atrial opening, a large number of coils of the vas deferens, cushion-shaped colonies with terminal common cloacal apertures and scattered red pigment granules in the tunic., Published as part of Page, M. J., Willis, T. J. & Handley, S. J., 2014, The colonial ascidian fauna of Fiordland, New Zealand, with a description of two new species, pp. 1653-1688 in Journal of Natural History (J. Nat. Hist.) (J. Nat. Hist.) 48 (27 - 28) on pages 1676-1678, DOI: 10.1080/00222933.2014.896487, http://zenodo.org/record/5193878, {"references":["Michaelsen, W. 1921. Ascidien vom westlichen Indeschen Ozean aus dem Reichmuseum zu Stockholm. Arkiv foer Zoologi. 13: 1 - 25.","Kott, P. 1977 Algal-supporting didemnid ascidians for the Great Barrier Reef. In: Proceedings of the Second International Coral Reef Symposium; Maiami: University of Maiami.","Kott, P. 1980. Algal-bearing didemnid ascidians in the Indo-west Pacific. Memoirs of the Queensland Museum. 20: 1 - 47.","Hartmeyer, R. 1913. Tunicata. In: L Schaltze (ed), Zoologische und Antropologische Ergebnisse einer For schungsreise im Westlichen und Zentrelen Sudafrica ausgefuhrt in den Jaren 1903 - 1905. Bd. 5. Denkschriften der Medizinisch-naturwissenschaftlichen Gesellschaft zu Jena 17: p. 124 - 144."]}