Isognomon (Parviperna) nucleus ( Lamarck, 1819 )

Raines, Bret & Huber, Markus, 2012, 3217, Zootaxa 3217, pp. 1-106 : 25-26

Isognomon (Parviperna) nucleus ( Lamarck, 1819)

Figures 11 C–D

Perna nucleus Lamarck, 1819: p. 68 .

Perna pectinata Reeve, 1858b : sp. 2, pl. 1, fig. 2.

Isognomon pectinata — Osorio, 1995: p. 200, figs. 2–3, 5; Tröndlé & Boutet, 2009: p. 5.

Isognomon nucleus ( Lamarck, 1819) — Tröndlé & Boutet, 2009: p. 5.

Isognomon (Parviperna) sp. cf. nucleus (Lamarck, 1836) — Brook & Marshall, 1998: p. 212; Spencer et al., 2011: p. 1. Isognomon (Parviperna) nucleus ( Lamarck, 1819) — Oliver, 1992: p. 68, pl. 11; Huber, 2010: p. 176, fig. 6.

Material examined. Illustrations of the two live collected specimens, and one pair of matching valves, which were provided to us for this study (Osorio, pers. comm., 2010).

Diagnosis. Shell small, obliquely-subovate, fairly solid and not fragile. Exterior surface of course commarginal lamellae, and usually encrusted. Interior smooth and nacreous, ventral margin the same color as the exterior. Hinge stout, consisting of numerous elongate teeth. Color variable, brownish-purple to greyish-black.

Remarks. Isognomon (Parviperna) pectinata was synonymized with P. nucleus by Lamy (1933), and accepted by subsequent authors. The species recorded as I. pectinata by Osorio (1995) matches the widely distributed P. nucleus well.

Habitat. Two matching valves of a fresh dead specimen (14.3 x 12.5 mm) were collected from the intertidal zone, (near Vaihu), while two other live specimens (2.6 x 2.3 mm & 4.6 x 3.3 mm) were collected from a depth of 20 m, attached to a colony of Pocillopora (off Motu Kaokao).

Distribution. Isognomon (Parviperna) nucleus is widely distributed throughout the Indo-Pacific, from South Africa to the Kermadec Islands including the Society Islands, Marquesas Islands, Tuamotu Archipelago, Gambier Islands, Austral Islands, Pitcairn Islands, eastern Australia and Easter Island. However, it is not known from the Hawaiian Islands— E5.