Cryptopora Jeffreys, 1869

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 : 426-427

Genus Cryptopora Jeffreys, 1869

TYPE SPECIES. — Cryptopora gnomon Jeffreys, 1869 , by monotypy ( Jeffreys 1869: 136).

Cryptopora maldivensis Muir-Wood, 1959 (Figs 3D-N)

Cryptopora maldivensis Muir-Wood, 1959: 293 , 294, text-fig. 2; pl. 5, figs 1, 3-7. — Zezina 1985: 113.

MATERIAL EXAMINED. — Wallis and Futuna. MUS- ORSTOM 7, Wallis, stn DW 601, 1 complete specimen.

Fiji. MUSORSTOM 10, Bligh Water, stn DW 1314, 2 complete specimens. — Stn CP 1330, 3 complete specimens. — Stn CP 1331, 4 complete specimens. — Stn CP 1332, 13 complete specimens. — Stn DW 1333, 1 complete specimen. — Stn DW 1334, 1 complete specimen. — Stn CP 1341, 60 complete specimens. — Stn DW 1345, 6 complete specimens. — Viti Levu, stn CP 1353, 19 complete specimens. — Stn CP 1354, 1 complete specimen. — Stn DW 1384, 2 complete specimens. — Stn CP 1390, 6 complete specimens.

DEPTH RANGE. — 200- 963 m.

MEASUREMENTS. — See Table 3; see also Figure 4.

DESCRIPTION Shell very small (maximum observed length is 3.7 mm), variable in outline from subtriangular to elongate oval, very thin and translucent. Surface iridescent,smooth, apart from very fine, widely spaced

)

mm

(

Width

Length (mm)

capillae better visible on the anterior half (Fig. 3J); growth lines numerous. The secondary layer fibres are readily visible on the surface and form a mosaic. Shell very weakly biconvex. Anterior commissure rectimarginate. Beak high and pointed with sharp beak ridges. Foramen large, triangular, hypothyrid, bordered by two narrow, elevated deltidial plates. Ventral valve interior with short teeth supported by distinct divergent dental plates (Fig.3N). Dorsal valve interior with very high but short median septum, small cardinal process in form of depression, and slender crura of maniculiform type (Fig. 3K, L).

REMARKS

Cryptopora maldivensis is one of the commonest species (about 115 specimens) in the investigated material. The studied specimens are consistent with the description given by Muir-Wood (1959), differing only in smaller size; the type material reaches about 5 mm.

In outline and type of the deltidial plates C. maldivensis is similar to C. gnomon but it differs in being less convex and rectimarginate, while C. gnomon is sulcate ( Cooper 1959). The shell of C. gnomon also lacks capillae.

This is the first record of Cryptopora from Fiji, and Wallis and Futuna islands although this genus was identified in the Pliocene deposits of Fiji ( Cooper 1978). Cryptopora maldivensis was not found on the Lau Ridge.

Figures

FIG. 4. — Intraspecific variation in Cryptopora maldivensis Muir- Wood, 1959. Scatter diagram plotting length/width. N, number of specimens.