taxonID	type	description	language	source
03CD7E00685A697D44FE6396FB5DEDF7.taxon	type_taxon	Type species. Chiton cinereus sensu Montagu, 1803 (non Linnaeus, 1767) = Leptochiton asellus (Gmelin, 1791) fide Lovén (1846), by subsequent designation (Gray 1847). Genus distribution. Worldwide, Carboniferous – Recent, intertidal – 7,657 m (Sirenko 2020).	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00685A697D44FE616DFE85EAC6.taxon	description	(Figures 1 – 3)	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00685A697D44FE616DFE85EAC6.taxon	materials_examined	Type material. Holotype (ZSM Mol 20070760). Type locality. Chile, off Concepcion, 36 º 22.19 ’ S, 73 º 43.36 ’ W, 846 m. Material examined. Southern Ocean, Heard Island, 52.5969 ° S, 71.9952 ° E, Locality HIMI-Aurora Bank, 310 m, cruise SC 26, Mol 37, benthic sled, 6 spms, BL 10.0 – 14.5 mm, (TMAG, E 26178), 01.05.2003.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00685A697D44FE616DFE85EAC6.taxon	distribution	Distribution. Off Chile, from 34.5 ° S to the Magellan Strait and Beagle Channel, South Orkney, South Shetland, Kerguelen, Heard and Crozet Islands, south western Australia and New Zealand, 88 – 1210 m (Sirenko 2020).	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00685A697D44FE616DFE85EAC6.taxon	discussion	Remarks. The studied specimen (TMAG E 26178) has BL 11.0 mm and 10 gills per side arranged from valve VII to anus, and a 4.3 mm long radula with 57 transverse rows of mature teeth. Like specimens of this species living off the South Shetland Islands (Sirenko 2015), the Australian specimens I studied (Sirenko 2020) have smooth dorsal scales, which in my opinion is intraspecific variability. Leptochiton laurae belongs to the group of L. sykesi (Sirenko 2020).	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00685A697A44FE67BAFBD7EE2F.taxon	description	(Figures 4 – 6)	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00685A697A44FE67BAFBD7EE2F.taxon	materials_examined	Type material. Neotype (AM C. 10410), designated by Iredale & Hull (1925). Type locality. South Australia, Yorke Peninsula, Hardwicke Bay. Material examined. Tasmania, D’Entrecasteaux Channel, 43 ° 13 ’ S, 147 ° 28 ’ E, 18 m, 2 spms, BL 9.5 – 10.0 mm, (TMAG, E 3035), 1910, coll D. L. May.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00685A697A44FE67BAFBD7EE2F.taxon	discussion	Remarks. The studied two specimens were collected and identified by D. L. May as a new species Lepidopleurus profundus May, 1923. Kaas & Van Belle (1985) identified them as Leptochiton liratus. The examination under an electron microscope revealed that the dorsal scales of these specimens are longer and pointed. They are similar to the needle-like spicules of the very similar species L. collusor (Iredale & Hull, 1925), while the dorsal scales of L. liratus have a different shape (see Kaas & Van Belle 1985). The identification as L. liratus by Kaas & Van Belle (1985) is accepted herein until the validity L. liratus and L. collusor is clarified.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00685D697644FE663BFC43E8AD.taxon	description	(Figures 7 A, B, 8 – 14)	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00685D697644FE663BFC43E8AD.taxon	materials_examined	Type material. Holotype (TMAG, E 45530) and paratype (TMAG, E 45531), both now disarticulated consisting of SEM stub of valves I, II, IV, V, VIII, part of perinotum and radula, mount of part of perinotum and vial with other valves. Type locality. Southern Ocean, South of Tasmania, 44.3511 ° S, 147.2868 ° E, 1450 m (Huan MP: 744 seamount: stn SS 2008 _ VOL _ 030, Lot 030, dredge CSIRO, 19.01.2008). Material examined. Southern Ocean, South of Tasmania, 44.3511 ° S, 147.2868 ° E, 1450 m, Huan MP: 744 seamount: stn SS 2008 _ VOL _ 030, Lot 030, dredge CSIRO, holotype (TMAG, E 45530) BL 9.0 mm, 19.01.2008; 45.1345 ° S, 146.0161 ° E, 1520 m, Fracture MP: The Knob stn SS 2008 _ VOL _ 037, Lot 037, dredge CSIRO, paratype (TMAG, E 45531) BL 15.5 mm, 22.01.2008.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00685D697644FE663BFC43E8AD.taxon	etymology	Etymology. Named after Karen Gowlett-Holmes, a leading marine biologist of Australia, for her large contribution to the knowledge of Australian marine animals including chitons, and for her beautiful photographs of fishes and invertebrates.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00685D697644FE663BFC43E8AD.taxon	distribution	Distribution. Only known from the type material.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00685D697644FE663BFC43E8AD.taxon	diagnosis	Diagnosis. Small to moderately sized chiton, valves lowly elevated, subcarinated, head valve noticeably wider than tail valve. Tegmentum sculptured with small, flattened granules arranged in longitudinal rows in central area of intermediate valves and antemucronal area of tail valve, and in a random manner in other areas. Jugal sinus wide, twice as wide as width of apophyses. Girdle very narrow, about 100 – 130 μm wide in valve V, covered with pointed, smooth dorsal scales that are very sharp on top. Major lateral radular tooth with long, unidentate cusp.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00685D697644FE663BFC43E8AD.taxon	description	Description. Small chiton, BL 9.0 mm, elongate oval. Valves only little elevated (dorsal elevation of valve V 0.33), subcarinated, not beaked. Color of tegmentum white. Head valve semicircular. Intermediate valves broadly rectangular, anterior margin strongly convex in valve II, straight in valves II – VII, posterior margin straight, sides rounded, apex not projecting. Tail valve noticeably narrower than head valve, mucro postmedian, antemucronal slope convex, postmucronal slope slightly concave. Tegmentum sculptured with small flattened granules arranged in longitudinal rows in central area of intermediate valves and antemucronal area of tail valve and in a random manner in head valve, lateral areas of intermediate valves and postmucronal area of tail valve. Each granule with one megalaesthete and two micraesthetes. Articulamentum white, weakly developed, apophyses narrow, triangular in intermediate valves, trapezoidal in tail valve, jugal sinus wide, twice wider than width of apophyses in valve V. Girdle very narrow, about 100 – 130 μm wide in valve V, dorsally covered with pointed, smooth scales (74 × 20 μm) with very sharp top, and rare smooth needles (100 – 110 × 15 μm). Intersegmental area with long needles (173 × 17 μm). Marginal needles like intersegmental ones but shorter (130 × 16 μm). Ventrally girdle covered with elongate pointed, smooth scales (85 – 100 × 25 μm). Radula of holotype 4.1 mm long with 51 transverse rows of mature teeth. Central tooth elongate with narrow blade, major lateral tooth with long, unidentate cusp. Nine short gills per side arranged from valve VI to anus. Gut content of both type specimens containing detritus, sand and several foraminifers.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00685D697644FE663BFC43E8AD.taxon	discussion	Remarks. The paratype, BL 15.5 mm has radula 6.9 mm long with 51 transverse rows of mature teeth and 11 short gills per side arranged from valve VII to near the anus. Age-related variability was observed: with age, the intermediate valves become more elongated and oval rather than rectangular. Leptochiton gowlettholmesae n. sp. differs from other species with similar radular teeth and a similar sculpture of the tegmentum (Leptochiton lascrusesi Sirenko, 2015, from Chile and L. commandorensis Sirenko, 2017, from Commander Islands) by having a very narrow girdle with pointed, smooth dorsal scales that are very sharp on top (vs. dorsal scales wide with ribs in both above mentioned species).	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006857697044FE63D8FCDDE81C.taxon	description	(Figures 15 – 18)	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006857697044FE63D8FCDDE81C.taxon	materials_examined	Type material. Holotype (AM C. 32026). Type locality. Off Cape Wiles, S. Australia, 34 ° 56 ’ 44.3 ’’ S, 135 ° 41 ’ 3.3 ’’ E, 180 m. Material examined. South of Australia, Great Australian Bight: 200 km W of S Eyre Peninsula 35.1406 ° S, 134.2747 ° E, 450 m, CMAR Voyage stn SS 2008 _ 03 _ 069, Lot 069, Sherman sled, CSIRO, 1 spm (TMAG, E 45529) BL 7.5 mm, 06.03.2008.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006857697044FE63D8FCDDE81C.taxon	distribution	Distribution. South Australia, Australian Bight, W of S Eyre Peninsula, 180 – 450 m. Given the very short initial description of this species by Iredale & Hull (1925), I decided to give a more extended description of the present specimen.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006857697044FE63D8FCDDE81C.taxon	description	Description. Small chiton, BL 7.5 mm. Valves thick, highly arched (elevation ratio 0.57 in valve V), not beaked. Second valve is 1.1 times wider than the fifth. Color of tegmentum white. Head valve absent. Intermediate valve long, oval, lateral area not raised, anterior margin waved in valves III – VIII, lateral margins rounded, posterior margin convex. Tail valve triangular in outline, mucro postmedian, antemucronal slope convex, postmucronal slope slightly concave. Tegmentum uniformly sculptured with flattened, hardly separated, quincuncially arranged granules. Each granule with one megalaesthete and four micraesthetes in front, pores of megalaesthete a little larger than micraesthetes. Articulamentum well developed, apophyses small, widely separated, jugal sinus about twice as wide as apophyses. Girdle narrow (about 0.3 mm near valve V), dorsally covered with obtusely pointed, slightly bent, wide scales (60 x 40 μm) with six – eight distinct longitudinal riblets. Two kinds of flattened marginal needles: obtusely pointed, with ribs (115 x 18 μm), and sharply pointed, smooth (100 x 18 μm). Girdle ventrally covered with elongate, smooth, bluntly pointed scales (one row near margin) (60 x 30 μm), and sharply pointed, smooth scales (50 x 19 μm) in other part of hyponotum. Radula of studied specimen 4.2 mm long with 26 transverse rows of mature teeth. Central tooth wide, first lateral teeth narrow with small blade, major lateral teeth with unidentate sharp cusps. Distal part of third uncinal teeth rounded.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006857697044FE63D8FCDDE81C.taxon	discussion	Remarks. The examined specimen was collected in the Great Australian Bight, not far from Cape Wiles, the type locality of this species. All features of the newly found specimen coincide with those of the holotype, therefore, this is the second find of this rare species. Belknapchiton opiparus superficially resembles most species of the genus, but differs from them by the width of the second valve. Unlike other species of this genus, B. opiparus has a second valve that is wider than all other valves. In addition, some of the marginal needles are ribbed in this species. Belknapchiton opiparus differs from B. okamurai (Saito, 2001), B. bergenhayni (Saito, 2011), and B. fijiensis (Sirenko, 2016), which also have ribbed marginal needles by having five pores of aesthetes in granules of the central area (vs. 7 – 13 pores in the mentioned species).	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006857697044FE62FEFAC7EE2A.taxon	type_taxon	Type species. Leptochiton belknapi Dall, 1878, by original designation (Sirenko, Saito & Schwabe 2022). Genus distribution. Pacific Ocean, from Asia to America and from Bering Sea to south Australia and New Zealand, Indian and Atlantic oceans. Recent-Pliocene, 20 – 4600 m, mainly deeper 200 m (Sirenko et al. 2022).	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006854696F44FE678CFCBBEEE7.taxon	description	(Figures 7 C, D, 19 – 22)	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006854696F44FE678CFCBBEEE7.taxon	materials_examined	Type material. Holotype (TMAG, E 45530), now disarticulated consisting of SEM stub of valves I, II, IV, V, VIII, part of perinotum and radula, mount of part of perinotum and vial with other valves. Type locality. Australia, S Tasmania slope, 44.2012 ° S, 146.1992 ° E, 1050 – 1230 m. Material examined. New Zealand, Kermadec Islands, NNE of Herald Islets, Raoul Island, 29 ° 12.00 ’ S, 177 ° 49.30 ’ W, R / V Acheron, stn 1973312, 1188 – 1225 m, 1 spm (NMNZ M 222132) BL 16.0 mm, 05.04.1973; Australia, S Tasmania slope, 44.2012 ° S, 146.1992 ° E, 1050 – 1230 m Southern Surveyor stn 50 Lot 50, Sherman sled, CSIRO, holotype (TMAG, E 45527) BL 13.0 mm, 06.04.2007.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006854696F44FE678CFCBBEEE7.taxon	etymology	Etymology. From the Latin australis, south.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006854696F44FE678CFCBBEEE7.taxon	distribution	Distribution. Southern Ocean, Off Tasmania and Kermadec Islands, 1188 – 1225 m.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006854696F44FE678CFCBBEEE7.taxon	diagnosis	Diagnosis. Animal rather small, elevated, valves rather long, arched, not beaked, tail valve triangular, mucro postmedian, postmucronal slope straight; tegmentum sculptured by small triangular granules arranged in quincunx; each granule with one megalaesthete and 2 – 4 micraesthetes, surface between granules noticeably striated; dorsal scales sculptured with three to six fine, barely visible riblets; central teeth of radula wide, major lateral teeth with sharply pointed, unidentate head with small denticle-like appendix at inner edge; twelve gills per side.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006854696F44FE678CFCBBEEE7.taxon	description	Description. Holotype (BL 13.0 mm) elongate oval in outline. Valves arched, moderately elevated (elevation ratio 0.45 in valve V), not beaked. Tegmentum white. Head valve semicircular, wider than tail valve, posterior margin widely V-shaped. Second valve oval, anterior and posterior margins convex. Other intermediate valves almost rectangular, lateral areas not raised, anterior margin slightly concave in central part, posterior margin weakly convex, lateral areas not raised. Tail valve triangular, mucro postmedian, antemucronal slope slightly convex, postmucronal slope straight. Tegmentum uniformly sculptured with triangular granules arranged quincuncially, each granule with one megalaesthete and two – four micraesthetes. Surface between granules noticeably striated. Articulamentum well developed for this genus, apophyses small, widely separated, subtriangular in valves II – VII, more or less trapezoidal in tail valve, jugal sinus twice as wide as apophyses. Girdle narrow (0.5 mm near valve V), dorsally covered in elongate, slightly curved, pointed scales, sculptured with three to six fine, barely visible riblets (85 – 90 x 35 – 36 μm), marginal needles smooth, not numerous (160 x 15 μm). Ventral scales lanceolate, smooth (70 x 15 μm). Radula 5.6 mm long with 29 transverse rows of mature teeth, somewhat assymmetrical. Central teeth wide with round, narrow blade, major lateral teeth with sharply pointed, unidentate head with small denticle-like apendix at inner edge. Twelve gills per side extending from valve VII to anus. Gut containing foraminifera and detritus.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006854696F44FE678CFCBBEEE7.taxon	discussion	Remarks. The second specimen of this species (Leptochiton cf. opiparus) collected off Kermadek Islands (identified as Leptochiton cf. opiparus by Sirenko 2020) closely resembles the holotype in the shape of the valves, the sculpture of the tegmentum, the weak development of the ribs on the dorsal scales and the general shape of the teeth of the radula, However, it differs in some minor details: in the shape of the valves, the sculpture of the tegmentum, the weak development of the ribs on the dorsal scales and the general shape of the radular teeth, the blade of the central radular teeth is straight, not curved, and the radula is symmetrical. However, I consider these differences as intraspecific variability. This is the second species of the genus Belknapchiton in the Southern Ocean. The new species differs from B. opiparus in having weakly developed, thin riblets on the dorsal scales (vs 6 – 8 distinct ribs in B. opiparus), valve II is narrower than valve III (vs valve II widest in B. opiparus), smooth marginal needles (vs. part of the marginal needles with ribs in B. opiparus).	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006848696F44FE60EDFDADEC08.taxon	type_taxon	Type species. Chiton albus Linnaeus, 1767, subsequently designated by Winckworth (1926). Genus distribution and range. All oceans in cold and temperate waters, usually not more than 14 ºC, intertidal to 4572 m. Miocene – Recent (Sirenko 2023).	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006848696A44FE61E0FC24EB5B.taxon	description	(Figures 23 A, B 24 – 26)	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006848696A44FE61E0FC24EB5B.taxon	materials_examined	Type material. Two syntypes (NHMO D 33573). Type locality. Norway, Bodö (67 ° 17 ’ N, 14 ° 25 ’ E) and Florö (61 ° 36 ’ N, 5 ° 0 ’ E), 180 – 360 m. Material examined. Southern Ocean, Macquarie Islands, R / V Dmitry Mendeleev, cruise 16, stn 1294, 54 ° 56.5 ’ S, 158 ° 49.7 ’ E, 320 m, Sigsby trawl, 4 spms, BL 11.0 – 14.0 mm, 25.01.1976; Macquarie Islands, offshore to W, 54.7119 ° S, 158.7679 ° E, 200 – 468 m, stn SS 1999 _ 01 _ 060 Lot _ 60, Benthic dredge, CSIRO, 1 spm (TMAG, E 45537) BL 16.0 mm, 22.01.1999. Macquarie Islands, offshore to E, 54.5959 ° S, 158.9433 ° E, 250 – 500 m, stn SS 1999 _ 093 Lot _ 093, Benthic dredge, CSIRO, 28 spm (TMAG, E 45535) BL 10.5 – 17.0 mm, 26.01.1999; Southern Tasmania Slope: Southern Sirveyor, 44.0306 ° S, 147.5796 ° E, 830 – 1030 m, stn SS 0207 _ 08 _ Lot _ 8, Sherman sled, CSIRO, 2 spm (TMAG, E 45526) BL 11.0 – 12.0 mm, 31.03.2007.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006848696A44FE61E0FC24EB5B.taxon	distribution	Distribution. Wide-spread species. It inhabits the Atlantic Ocean from Greenland, Iceland, Norway up to Terra del Fuego, South Shetlands and South Orkney Islands, Pacific Ocean near Southern Chile, Indian Ocean near Prince Edward, Kerguelen and Amsterdam Islands. The four above mentioned samples of this species are the first find for South Australia and Macquarie Islands. The species lives at depths from 23 up to 2580 m (Kaas & Van Belle 1990; Schwabe & Sellanes 2010).	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006848696A44FE61E0FC24EB5B.taxon	discussion	Remarks. The specimen (TMAG, E 45526, BL 11.5 mm) studied under SEM has 21 gills on each side arranged from valve IV to the anus; radula 4.1 mm long with 31 transverse rows of mature teeth. Gut content contains detritus (50 %), foraminifera (40 %, about 100 % calcareous shells) and sand (10 %). The studied specimen collected south of Tasmania, as well as individuals collected from Macquarie, differs from Norwegian individuals in the almost complete absence of radial grooves on the postmucronal area of the tail valve and the presence of granules on the top of the dorsal calcareous corpuscles (not metioned in the description by Kaas & Van Belle 1990).	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00684D696A44FE660AFBDDE8D3.taxon	description	(Figures 23 C, D, 27 – 32)	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00684D696A44FE660AFBDDE8D3.taxon	materials_examined	Type material. Holotype (ZMB Moll 59908). Type locality. South Africa, Cape of Good Hope, 318 m. Material examined. Holotype, Southern Ocean, Heard Island, 52.3889 ° S, 72. 6272 ° E, Locality HIMI-Western Platean, 302 m, cruise SC 26, Haul N 161 B, 2 spms, BL 20.0 mm, (TMAG, E 26179), 01.05.2003. 52.5969 ° S, 71. 9952 ° E, Locality HIMI-Aurora Bank, 310 m, cruise SC 26, Mol 37, benthic sled, 6 spms, BL 10.0 – 14.5 mm, (TMAG, E 26178), 30.04.2003.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00684D696A44FE660AFBDDE8D3.taxon	distribution	Distribution. Stenosemus simplicissimus is wide distributed species in the South Ocean. It was found near South America (Shag Rocks near South Georgia Island), near Antarctica (eastern Weddell Sea), near South Africa (Cape off Good Hope) and Heard Island. The latest find has greatly expanded the range of this species. The species inhabits depth from 284 to 1064 m (Schwabe 2008).	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E00684D696A44FE660AFBDDE8D3.taxon	discussion	Remarks. Holotype (RMNH. MOLL. K. 5155) has a somewhat glossy tegmentum, dorsal corpuscles with short longitudinal riblets in the upper part and with granules on the top. The studied specimens (BL 7.0 mm and 20.0 mm) from Heard Island have 9 – 10 longitudinal riblets on all dorsal surface of the corpuscles and have no granules on the top of the corpuscles. The larger specimen has 23 gills per side arranged from valve III to valve VII. The radula of the smaller specimen is 3.4 mm long and has 28 transverse rows of mature teeth.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006843696444FE67DCFD13E937.taxon	type_taxon	Type species. Stenochiton juloides H. Adams & Angas, 1864 (= Chiton longicymba de Blainville, 1825), by monotypy. Genus distribution. South and Western Australia. Shallow subtidal up to 94 m, on the leaves of sea-grasses (Kaas & Van Belle 1994, Kaas et al. 2006 and own data).	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006843696544FE64A6FD26EE0B.taxon	description	(Figures 33 C, D)	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006843696544FE64A6FD26EE0B.taxon	materials_examined	Type material. Lectotype (ANS 69142). Type locality. South Australia, Gulf St. Vincent, Troubridge Shoal. Material examined. Australia, Western Australia, Indian Ocean, 31 ° 71 ’ S, 115 ° 25 ’ E, 94 m. Southern Surveyor stn 50 Lot _ 28, CSIRO, 1 spm (TMAG, E 45527) BL 13.0 mm, 12.05.2007.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006843696544FE64A6FD26EE0B.taxon	distribution	Distribution. Western & South Australia, shallow subtidal up to 94 m (Kaas & Van Belle 1994 and own data.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006843696544FE64A6FD26EE0B.taxon	discussion	Remarks. The morphological features of the specimen collected from Western Australia fully corresponds to its description as given by Kaas & Van Belle (1994).	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006842696744FE6415FAD3E9A5.taxon	description	(Figures 33 A, B, 34 – 36)	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006842696744FE6415FAD3E9A5.taxon	materials_examined	Type material. Holotype (SAMA 011728). Type locality. South Australia, Gulf St. Vincent, dredged. Material examined. TAS: Tasman Sea, Tamboon, 10 km to SE Lot _ 60, 37.81 ° S, 149.0099 ° E, Benthic dredge, CSIRO, 1 spm (TMAG, E 45527) BL 9.5 x 6.0 mm, 26.11.1996.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006842696744FE6415FAD3E9A5.taxon	distribution	Distribution. South Australia, Gulf St. Vincent and Tasman Sea, 18 m (Kaas et al. 2006) The latest find significantly expands the range of this species.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
03CD7E006842696744FE6415FAD3E9A5.taxon	discussion	Remarks. Cochran (1993) and Kaas et al. (2006) mentioned that this species is more than 2.5 times longer than wide. The specimen collected near Tasmania (TMAG, E 45527) is noticeable shorter than the type specimen. The long body is one of the characteristic features of the species of this genus living on the long leaves of sea grasses. Our specimen has a short body and, apparently, with age, its body rapidly lengthens. It is clearly visible on all valves that growth along the anterior-posterior axis exceeds lateral growth by far. The studied specimen (TMAG, E 45527) has slit formula 0 / 1 – 2 / 10, dorsal elevation 0.45, 16 gills per side arranged from valve II to valve VIII.	en	Sirenko, Boris (2023): A small collection of rare and new chitons (Mollusca: Polyplacophora) from the Tasmanian Museum and Art Gallery. Zootaxa 5325 (3): 359-392, DOI: 10.11646/zootaxa.5325.3.3
