Leptochiton cf. laurae Schwabe & Sellanes, 2010

Sirenko, Boris, 2020, New Zealand and Australian species of the genus Leptochiton (Mollusca Polyplacophora), Zootaxa 4851 (3), pp. 401-449 : 417

Leptochiton cf. laurae Schwabe & Sellanes, 2010

( Figures 18–21 , 44G, H )

Leptochiton cf. sykesi Sirenko & Gallardo 2005: 89 [non Leptochiton sykesi (Sowerby III, 1903) ]

Leptochiton laurae Schwabe & Sellanes 2010: 37–41 , Figs. 1J , 4 , 5 A–D; Sirenko 2015: 161 , figs. 8A–C, 9–16; Sirenko & Sellanes 2016: 264 , figs. 1E, 9–11.

Type material. Holotype ( ZSM Mol 20070760).

Type locality. Chile, off Concepcion , 36º22.19’S, 73º43.36’W, 846 m.

Material examined. New Zealand, South Island , off Palliser Bay, 41°42.30’S, 175°9.00’E, F/ V Admiral , stn 1957083, 1006 m, 2 spm, BL 5.0–8.0 mm, ( NMNZ M 012864 ), 17.02.1957 ; SW of Kaikoura Peninsula , upper Kaikoura Canyon, 42°29.00’S, 173°37.00’E, R / V Acheron, stn 1976545, 1006– 1097 m, mud, 1 spm, BL 11.0 mm, ( NMNZ M 051009 ), 18.03.1976 ; South Island , SSE of Kaikoura, 42°49.90’S, 173°48.40’E, R / V James Cook , stn 1986020, 927– 995 m, 1 spm, BL 10.5 mm, ( NMNZ M 319764 ), 10.05.1986 ; North Island , southern Kermadec Ridge, Rumble Volcano, 36°8.37’S, 178°1292’E, R / V Tangaroa, stn TAN0107/231, 1210– 1040 m, 1 spm, BL 13.5 mm, ( NMNZ M 319773 ), 24.05.2001 .

Distribution. Off Chile, from 34.5°S to the Magellan Strait and Beagle Channel, South Orkney, South Shetland, Kerguelen and Crozet Islands and New Zealand, 88–1210 m. The present report near New Zealand of L. cf. laurae would greatly extend the previously known distribution of this species if confirmed.

Remarks. The examined specimen (NMNZ M 051009, with BL 11.0 mm) has 11 gills per side arranged from valve VI to anus, and a 3.0 mm long radula with 30 transverse rows of mature teeth. The New Zealand material shows some differences to the holotype and to some specimens studied by Sirenko (2015) and Sirenko & Sellanes (2016). The examined specimen differs from the holotype by having 1 or 2 ribs on dorsal scales [vs. 6–8 very faint longitudinal ribs in the holotype ( Schwabe & Sellanes 2010)]. In my opinion the number of ribs on dorsal scales is variable in this species. Specimens from South Shetland Islands were shown ( Sirenko 2015) to have smooth scales, while those from New Zealand and the Magellan region have 1–2 ribs and the specimens from Northern Chile have 3 ribs. Compared to the previously studied material, the specimens from New Zealand have a longer antemucronal area and rounded valves. As was mentioned by Sirenko (2015) and Sirenko & Sellanes (2016) L. laurae belongs to the group of L. sykesi .

Figures

FIGURE 1. Leptochiton badius, Northern coast of Tasmania, BL 7.0 mm, (ZISP 2382). A. Valve I, dorsal view; B. Valve II, dorsal view; C. Valve V, dorsal view; D. Valve VIII, dorsal view; E. Valve V, rostral view; F. Valve V, tegmentum sculpture in central area; G. Valve VIII, lateral view; H. Valve VI, ventral view.

FIGURE 4. Leptochiton badius, Northern coast of Tasmania, BL 7.0 mm, (ZISP 2382). A. Sutural needle; B. Dorsal scales; C. Marginal needle; D. Marginal spicule; E. Ventral scale near margin; F. Ventral scale from mid-girdle; G. Central tooth and first lateral teeth; H. Heads of major lateral teeth; I. Aesthete group in central area. Scale bar 50 μm.

FIGURE 5. Leptochiton beui n. sp., holotype, BL 3.5 mm, (NMNZ M 149935). A. Valve I, dorsal view; B. Valve V, dorsal view; C. Valve VIII, dorsal view; D. Valve VI, ventral view; E. Valve V, rostral view; F. Valve V, tegmentum sculpture in central and lateral areas; G. Valve VIII tegmentum sculpture near mucro; H. Valve VIII, lateral view.

FIGURE 18. Leptochiton cf. laurae, New Zealand, SW of Kaikoura Peninsula, upper Kaikoura Canyon, 1006-1097 m, mud, BL 11.0 mm, (NMNZ M 051009). A. Valve I, dorsal view; B. Valve V, dorsal view; C. Valve VIII, dorsal view; D. Valve VI, ventral view; E. Valve V, tegmentum sculpture in central and lateral areas; F. Valve V, rostral view; G. Valve VIII, lateral view.

FIGURE 19. Leptochiton cf. laurae, New Zealand, SW of Kaikoura Peninsula, upper Kaikoura Canyon, 1006–1097 m, mud, BL 11.0 mm, (NMNZ M 051009). A, B. Dorsal and ventral scales and needles; C. Dorsal scales and needles; D. Ventral scales.

FIGURE 20. Leptochiton cf. laurae, New Zealand, SW of Kaikoura Peninsula, upper Kaikoura Canyon, 1006–1097 m, mud, BL 11.0 mm, (NMNZ M 051009). A, B. Central portion of radula from anterior part.

FIGURE 21. Leptochiton cf. laurae, New Zealand, SW of Kaikoura Peninsula, upper Kaikoura Canyon, 1006–1097 m, mud, BL 11.0 mm, (NMNZ M 051009). A. Sutural and dorsal needle; B, C. Dorsal scales; D. Marginal needle; E. Ventral scale; F. Central and first lateral teeth of radula; G, H. Heads of major lateral tooth; I. Aesthete group in central area. Scale bar 50 μm (A–H).

FIGURE 44. Images of species of genus Leptochiton from New Zealand and Australia: A, B. L. cf. opiparus, New Zealand, Kermadec Islands, R/V Acheron, stn 1973312, 1188-1225 m, BL 16 mm, (NMNZ M 222132); C, D. L. marshalli n. sp., holotype, New Zealand, Three Kings Islands, Tasman Bay, Great Island, 6 m, BL 10.0 mm, (NMNZ M 117376); E, F. L. subantarcticus, New Zealand, Head of Pegasus Canyon, Pegasus Bay, 446 m, mud, BL 5.5 mm, (NMNZ M 152576); G, H. L. cf. laurae, New Zealand, South Island, SSE of Kaikoura, R/V James Cook, stn 1986020, 927–995 m, BL 10.5 mm, (NMNZ M 319764).