Fissidentalium transversostriatum ( Boissevain, 1906 )

Scarabino, Victor, 2008, New species and new records of scaphopods from New Caledonia, Mémoires du Muséum national d'Histoire naturelle 196, pp. 215-268 : 229

Fissidentalium transversostriatum ( Boissevain, 1906)

Dentalium transversostriatum Boissevain, 1906: 32 , pl. 4, fig. 23.

Other reference:

Fissidentalium shoplandi - Scarabino 1995: 248, fig. 55 (in part), 73a-b (non F. shoplandi Jousseaume, 1894 ). Material cited: 1 lot (2 spms) fom Loyalty Ridge, 594 m, shells only.

NEW MATERIAL EXAMINED. — New Caledonia proper. BATHUS 1: stn DE 697, Passe de Hienghène , 20°34’S, 164°58’E, 570- 650 m, 1 dd . — BATHUS 4: stn CP 948, Passe de Hienghène , 20°33’S, 164°57’E, 533-610 m, 1 dd .

DISTRIBUTION. — Global distribution: Indonesia, Philippines, live in 550-1030 m, New Caledonia. Distribution in

the New Caledonian region: east of New Caledonia and Loyalty Ridge, shells in 570- 610 m.

REMARKS. — Based on the material available at the time ( Indonesia, Philippines and New Caledonia), including the type specimens, Scarabino (1995) considered Fissidentalium transversostriatum to be a junior synonym of F. shoplandi (Jousseaume, 1894) . Since then, examination of a series of specimens of F. shoplandi from the western Indian Ocean has revealed enough differences to revalidate F. transversotriatum . The examined material of F. shoplandi includes: near Aden, 670 fms (USNM 107709), off Travancore coast, 360 fms (BMNH 1904.6.15.175-176), and specimens collected by the John Murray Expedition to the western Indian Ocean (BMNH 1952.3.25.167-171; 1952.3.25.157-166 and 1952.3.25.182-191) from depths of 533-1080 m ( Ludbrook 1954).

The main difference between Fissidentalium transversostriatum and F. shoplandi is in rib sculpture, and is especially clear in adult and well preserved specimens. Both species have dense transverse sculpture but while F. shoplandi has smooth cords scattered among threads crenulating the ribs, F. transversostriatum has regular elevated striae, which become scales and almost spinulose (Scarabino 1995: fig 73b), resembling the Coccodentalium sculpture type.