Novocrania sp.

Bitner, Maria Aleksandra, 2008, New data on the recent brachiopods from the Fiji and Wallis and Futuna islands, South-West Pacific, Zoosystema 30 (2), pp. 419-461 : 424

Novocrania sp.

(Fig. 3A-C)

MATERIAL EXAMINED. — Wallis and Futuna. MUS- ORSTOM 7, Wallis, stn DW 604, 1 dorsal valve.

Fiji. MUSORSTOM 10, Bligh Water, stn DW 1333, 9 dorsal valves. — Stn DW 1334, 1 dorsal valve.

DEPTH RANGE. — 200- 420 m.

MEASUREMENTS. — See Table 2.

DESCRIPTION

The investigated material consists of only dorsal valves. Shell small (maximum length: 6 mm), subcircular in outline with posterior margin nearly straight. Dorsal valve conical with the beak situated posterocentrally. Surface irregular with variably developed concentric growth lines; fine pustules are visible on some specimens. Interior valve with narrow rim. Posterior adductor muscle scars large and circular.Anterior adductor muscle scars relatively small, not reaching the margin, elevated above the inner surface. Brachial protractor scars prominent. No median ridge or septum.

REMARKS

Several species of craniids have been recognized in the southern Pacific. The investigated specimens differ from the New Zealand Novocrania huttoni ( Thomson, 1916) which possesses radial ornamentation ( Thomson 1916; Lee 1987). Novocrania indonesiensis ( Zezina, 1981) , is similar externally, but differs from the Fiji material in having muscle impressions indistinct and differently arranged; its posterior adductor scars are smaller, and anterior adductor muscle scars are not elevated. Externally, the specimens are also similar to N. lecointei (Joubin, 1901) but they differ from the latter species in much smaller size and larger and more distinct muscle scars ( Foster 1974).

The absence of the septum excludes the studied specimens from the genus Craniscus Dall, 1871 . However, the new data from molecular analyses of extant craniids show clearly that the recent species Craniscus japonicus (Adam, 1863) belong to a Neoancistrocrania -like cluster ( Cohen et al. 2008), and in consequence Craniscus should be restricted to the Upper Jurassic-Lower Cretaceous. The molecular results are also confirmed by the morphological observations, as recent specimens assigned to Craniscus lack the prominent median ridge seen in the Jurassic type species Crania tripartita von Münster, 1840 (see Lee & Brunton 1986). Dall (1920) assigned the recent brachiopod Crania japonica to Craniscus and this mistaken attribution has been repeated by all subsequent authors (see discussion in Cohen et al. 2008). Logan & Long (2001) already doubted whether recent Crania japonica Adams, 1863 should have been assigned to the essentially Upper Jurassic and Lower Cretaceous genus.