Eucalathis Fischer & Oehlert, 1890

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 : 434-437

Genus Eucalathis Fischer & Oehlert, 1890

TYPE SPECIES. — Terebratulina murrayi Davidson, 1878 by original designation ( Fischer & Oehlert 1890: 72).

Eucalathis rugosa Cooper, 1973 ( Fig. 9 )

Eucalathis rugosa Cooper, 1973a:388 , 389, text-fig.2, pl. 43, figs 1-9. — Zezina 1985: 135; 1987: 556. — d’Hondt 1987: 35. — Laurin 1997: 428, 429, figs 13a-c, 14.

DEPTH RANGE. — 260- 305 m.

DESCRIPTION

Shell very small (maximum length 2.9 mm), subquadrate to broadly triangular in outline, biconvex. Shell surface covered with 8-10 strongly granulated ribs; single intercalated ribs are also present. Beak fairly long, suberect. Foramen large, triangular, bordered by two narrow, obliquely elevated deltidial plates. Anterior commissure rectimarginate. Teeth short but wide.Pedicle collar well-developed.Dorsal valve interior with high inner socket ridges and weakly developed cardinal process. Crura very short with blunt crural processes. Loop short with relatively broad descending branches. Inner margin of both valves crenulated.

REMARKS

The investigated specimens are consistent in size, strong ornamentation and beak characters with Eucalathis rugosa . They differ, however, in having short intercalated ribs and broader descending branches. In the strong costation E. rugosa is similar to E. rotundata Cooper, 1981 , differing, however, in outline and beak characters.

In the Pacific Ocean this species was already recorded from Philippines and New Caledonia ( Cooper 1973a; d’Hondt 1987; Laurin 1997). Zezina (1987) mentioned the presence of E. rugosa in the Mozambique Channel, Indian Ocean. The occurrence of this species in the region of the Fiji and Wallis and Futuna Islands extends its geographic range farther to the east.

The genus Eucalathis is well-known in the southwestern Pacific ( Cooper 1973a; Dawson 1991; Laurin 1997; Bitner 2006a) but this is its first record from the Fiji and Wallis and Futuna regions.

Suborder TEREBRATELLIDINA Muir-Wood, 1955 Superfamily KINGENOIDEA Elliott, 1948 Family AULACOTHYROPSIDAE Dagys, 1972 Subfamily BABUKELLINAE MacKinnon, Smirnova & Lee, 2006

Figures

FIG. 9. — Eucalathis rugosa Cooper, 1973: A, B, dorsal and lateral views of complete specimen (MNHN BRA-3085), Fiji, Viti Levu, MUSORSTOM 10, stn DW 1384,260-305 m;C-F, complete specimen (MHNH BRA-3060),Wallis and Futuna,MUSORSTOM 7, stn DW 601, 350 m; C, D, outer and inner views of ventral valve; E, F, outer and inner views of dorsal valve; G-I, complete specimen (MNHN BRA-3086), Fiji, Viti Levu, MUSORSTOM 10, stn DW 1384, 260-305 m; G, H, dorsal view (G) and enlargement of posterior part (H); I, interior of dorsal valve with slightly broken brachidium. All SEM. Scale bars: A-G, 1 mm; H, I, 500 μm.