Kaasichiton lukini ( Sirenko, 1990 ) Sirenko, 2024

Sirenko, Boris I., 2024, A new genus and two new species of brooding chitons (Mollusca: Polyplacophora) from the North-Western Pacific, Zootaxa 5492 (4), pp. 505-529 : 509-512

Kaasichiton lukini ( Sirenko, 1990) n. comb.

( Figures 1–5 )

Leptochiton lukini n. sp.; Sirenko 1990: 97, figs 1, 3, 11.

Leptochiton (Leptochiton) lukini ; Kaas & Van Belle 1994: 17, fig. 5, map 50.

Type material. Holotype ( ZIN 1919 ) and 5 paratypes ( ZIN 1920 ).

Type locality. Kurile Islands , Chirpoy Island (holotype), 20 m.

Material examined. A total of 19 specimens. Kurile Islands, R/V Krilatka, Urup Island , the Okhotsk Sea , Schukin Inlet , SCUBA, sample 41, 20 m, stones, 1 spm, BL 3.5 mm, 08.09.1969 ; Van-der-Lind Cape , SCUBA, sample 65, 20 m, stones, 5 paratypes, ( ZIN 1920 ), BL 3.0–4.0 mm, 09.09.1969 ; Temniy Cape , SCUBA, sample 136, 15 m, stones, 1 spm, BL 4.0 mm, 18.09.1969 ; Temniy Cape , SCUBA, Khiva Cape , SCUBA, sample 152, 20 m, stones, 1 spm, BL 3.5 mm, 21.09.1969 ; Etolin Cape , SCUBA, sample 167, 10 m, stones, 1 spm, BL 3.0 mm, 23.09.1969 ; Kalashnikov Cape , SCUBA, sample 168, 10 m, stones, 1 spm, BL 4.0 mm, 23– 24.09.1969 ; Urup Island, Tair Island , SCUBA, sample 756, 20 m, rocks, 1 spm, BL 3.0 mm, 18.09.1970 ; Urup Island , Kitoviy Cape , SCUBA, sample 1058, 20 m, stones, 4 spms, BL 3.0–4.0 mm, 12.10.1973 Iturup Island , Urumpet Cape , trawl, sample 199, 51– 44 m, pebble and shells, 2 spms, BL 4.0 mm, 06.10.1969 ; Chirpoy Island , SCUBA, sample 538, 20 m, stones, holotype, ( ZIN 1919 ) BL 4.0 mm, 04.09.1970 ; Simushir Island , Polanskogo Cape , SCUBA, sample 645, 20 m, stones, 1 spm, BL 3.5 mm, 10.09.1970 ;

Distribution. Pacific Ocean, Kurile Islands, Iturup, Urup, Simushir and Chirpoy islands, 10– 44 m.

Remarks. When describing this species, Sirenko (1990) noted that this species had juveniles in the pallial groove.At the beginning of September, a female with 4 eggs in the pallial groove was encountered near Urup Island. The eggs were relatively large, (about 400 µm in diameter) compared to the eggs of chitons not brooding in pallial groove ( Sirenko 2015).

Figures

FIGURE 1. Kaasichiton lukini, Kurile Islands, Chirpoy Island, 20 m, holotype (ZIN 1919), BL 4.0 mm (A–C, E–G), Kaasichiton lukini, Kurile Islands, Urup Island, Van der Linde Cape, 20 m, paratype (ZIN 1920), BL 3.0 mm (D): A. Valve I, dorsal view; B. Valve V, dorsal view; C, D. Valves VIII, dorsal views; E. Valve V, detail of tegmentum surface of central area; F. Valve V, rostral view; G. Valve VIII, lateral view.

FIGURE 2. Kaasichiton lukini, Kurile Islands, Urup Island, Van der Linde Cape, 20 m, paratype (ZIN 1920), BL 3.0 mm: A, C. Dorsal spicules and needles; B, D. Radula.

FIGURE 3. Kaasichiton lukini, Kurile Islands, Chirpoy Island, 20 m, holotype (ZIN 1919), BL 4.0 mm: A. Sutural needle; B. Dorsal scale in middle of girdle; C. Dorsal scale near suture; D. marginal needle; E. ventral scale; F. Central and first lateral teeth of radula; I. Head of major lateral teeth of radula; J. Granule with aesthete pore. Scale bars 50 µm.

FIGURE 4. Kaasichiton lukini, Kurile Islands, Urup Island, Kitoviy Cape, 20 m, BL 3.0 mm: A. Valve I, dorsal view; B. Valve II, dorsal view; C. Valve V, dorsal view; D. Valve VIII, dorsal view; E. Valve V, detail of tegmentum surface of central area; F. Valve V, rostral view; G. Valve IV, ventral view; H. Valve VIII, lateral view.

FIGURE 5. Kaasichiton lukini, Kurile Islands, Urup Island, Kitoviy Cape, 20 m, BL 3.0 mm: A. Dorsal and ventral scales; B. Radula; C. Dorsal and ventral scales and marginal needles; D. Central and first lateral teeth of radula.