Fallax Atkins, 1960

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 : 437

Genus Fallax Atkins, 1960

TYPE SPECIES. — Fallax dalliniformis Atkins, 1960 , by original designation ( Atkins 1960: 72).

Fallax neocaledonensis Laurin, 1997 ( Fig. 10 H-J)

Campages furcifera – d’Hondt 1987: 37, pl. 1, figs 1-4.

Fallax neocaledonensis Laurin, 1997: 444-448 , figs 31-34, 46a-o. — Bitner 2006b: 27, fig. 5a-c.

Laurinia neocaledonensis – Zezina 2005: 31, 32.

MATERIAL EXAMINED. — Fiji. BORDAU 1, Lau Ridge, stn CP 1458, 1 complete specimen.

DEPTH RANGE. — 1216-1226 m.

MEASUREMENTS. — Length 15.5 mm, width 14.4 mm, thickness 10.2 mm.

REMARKS

Fallax neocaledonensis was originally described from the New Caledonia region where it is one of the most common species ( Laurin 1997; and pers. obs.). However, in the studied material it is very rare, although it has already been reported from the Fiji region ( Bitner 2006b). Fallax neocaledonensis is characterized by its widely triangular outline. Although externally similar to the dallinine brachiopods, it is easily distinguishable internally by the presence of distinct dental plates.

The specimens described earlier from the New Caledonia region by d’Hondt (1987) as Campages furcifera Hedley, 1905 , after examination of internal structures, appeared to possess distinct dental plates, which exclude them from Campages . On the contrary, they display all the characters typical of F. neocaledonensis and have been synonymised with the latter species in the present paper.

Recently Zezina (2005) transferred the species F.neocaledonensis into a new genus Laurinia , based on the absence of spicules in the specimens investigated by her from the Norfolk Ridge, New Caledonia, because spicules are observed in Fallax . It seems doubtful whether absence of spicules in a genus characterized by weak spiculation is sufficient to create a new genus.

Figures

FIG. 10.A, B, Argyrotheca sp., inner and lateral views of dorsal valve (MNHN BRA-3091),SEM,Fiji,Bligh Water,MUSORSTOM 10,stn DW 1334, 251-257 m; C-G, Frenulina sanguinolenta (Gmelin, 1791), SEM;C, D, inner and tilted views of dorsal valve (MNHN BRA-3089),Fiji, Beqa Lagoon,SUVA 4,stn DW 09,37-41 m;E-G, dorsal,lateral andanterior views of complete specimen (MNHN BRA-3090),Fiji,Lau Ridge, BORDAU1, stn DW1451,400-460m; H-J,Fallax neocaledonensis Laurin,1997,dorsal,lateral and anteriorviewsof completespecimen(MNHN BRA-3087),Fiji,Lau Ridge,BORDAU 1, stn CP 1458,1216-1226 m. Scale bars:A, B, 500 μm;C, D, 1 mm;E-G,2 mm; H-J,0.5 cm.