Leptochiton medinae Plate, 1899

Sirenko, Boris, 2015, Shallow and deep-sea chitons of the genus Leptochiton Gray, 1847 (Mollusca: Polyplacophora: Lepidopleurida) from Peruvian and Chilean waters, Zootaxa 4033 (2), pp. 151-202 : 159-160

Leptochiton medinae Plate, 1899

( Figs 5–7 )

Leptochiton medinae Plate 1899: 82 –89; pl.5, figs. 204–206; Kaas & Van Belle 1985: 80 –83; Sirenko 2006: 82; Schwabe & Sellanes 2010: 34 –36, Figs 1 K, 5E, F, 6, 7A, B

Type. Lectotype ( ZMB /Moll-102.045), designated by Schwabe & Sellanes (2010) (not examined).

Type locality. Chile, Magellan Strait, off Punta Arenas, 53º09’S 70º55’W, 15– 18 m.

Material examined. Magellan Strait and Beagle Channel. RV Victor Hensen, st. 881, AGT, 53°42.0’S, 70°57.4’W, 56 m, 1 spm, 26.10.1994, leg. K. Linse; st.884, EBS, 53°42.6’S, 70°57.5’W, 51 m, 6 spms, 26.10.1994, leg. K. Linse; st. 949, AGT, 53°10.5’S, 70°53.5’W, 24 m, 1 spm, 30.10.1994, leg. K. Linse; st. 972, EBS, 53°28.8’S, 70°21.9’W, 92 m, 10 spms, 0 1.11.1994, leg. K. Linse; st. 980, EBS, 53°42.7’S, 70°50.1’W, 552 m, 1 spm, 0 1.11.1994, leg. K. Linse; st. 1040, EBS, 54°51.0’S, 69°55.7’W, 30 m, 6 spms, 0 4.11.1994, leg. K. Linse; st. 1247, 54°59.43’S, 69°04.64’W, 100 m, 5 spms, 19.11.1994, leg. A. Brandt; st. 1316, AGT, 54°054’S, 70°58.3’W, 360 m, 1 spm, 24.11.1994, leg. K. Linse; Isla de los Estados. RV Eltanin, cruise 5, st. 453, 54°27’– 54°24’S, 66°12’– 66°17’W, 3 spms, 21.01.1963; RV Hero , cruise 712, st. 668, 54°46.25’S, 64°02.85’W, 23 m, 3 spms, 15.05.1971; Atlantic ocean, Argentina. RV Hero , st. G, 42°54.0’S, 64°23’W, 20–50 m, 16 spms, 18.07.1978.

Distribution. On both sides of southern South America from Lat.42° south to Cape Horn ( Kaas & Van Belle, 1985; Schwabe & Sellanes, 2010), at depth 8– 552 m.

Remarks. Schwabe & Sellanes (2010) erroneously reported an unicuspidate head of the second (major) lateral tooth of the radula in L. medinae . Kaas & Van Belle (1985) and the present data ( Fig.7 ) show a bicuspidate head of the major lateral tooth of the radula in L. medinae . The specimen figured in Schwabe & Sellanes (2010, Fig.5 , E, F) apparently shows the anterior-most part of the radula with worn denticles of the relevant teeth. I observed that the anterior most parts of the radula in several species including L. medinae , L. sykesi , L. laurae and others have unicuspidate head of the major lateral tooth because of the head was erased during process of feeding.

Figures

FIGURE 1. Leptochiton kerguelensis Haddon, 1864, (ZISP 2257). Beagle Channel, RV Victor Hensen, st. 1213. BL— 4.0 mm. A. Complete specimen, dorsal view; B. Complete specimen, lateral view; C. Valve I, dorsal view; D. Valve V, dorsal view; E. Valve VIII, dorsal view; F. Valve IV, ventral view; G. Valve VIII, lateral view; H. Valve V, rostral view.

FIGURE 5. Leptochiton medinae Plate, 1899, (ZISP 2258). Magellan Strait, RV Victor Hensen st. 884, BL— 5 mm. A. Valve I, dorsal view; B. Valve V, dorsal view; C. Valve VIII, dorsal view; D. Valve IV, ventral view; E. Valve V, detail of tegmentum surface of central area; F. Valve VIII, lateral view; G. Valve V, rostral view.

FIGURE 6. Leptochiton medinae Plate, 1899, (ZISP 2258). Magellan Strait, RV Victor Hensen st. 884, BL— 5 mm. A. Dorsal, marginal and ventral scales; B. Central portion of radula; C. Sutural and dorsal needles and scales; D. Dorsal scales.

FIGURE 7. Leptochiton medinae Plate, 1899, (ZISP 2258). Magellan Strait, RV Victor Hensen st. 884, BL— 5 mm. A. Sutural needle; B. Dorsal scale; C. Marginal needle; D. Marginal scale; E. Ventral scale; F. Central and first lateral teeth; G. Heads of major lateral tooth; H. Aesthete group in central area. Scale bar 100 µm (A – G).