Megathiris detruncata ( Gmelin, 1790 )

Bitner, Maria Aleksandra & Moissette, Pierre, 2003, Pliocene brachiopods from north-western Africa, Geodiversitas 25 (3), pp. 463-479 : 473-474

Megathiris detruncata ( Gmelin, 1790) ( Fig. 6G, H )

Megathiris detruncata – Logan 1979: 55-59, text-figs 15, 16; pl. 6, figs 1-13. — Gaetani & Saccà 1985a: 17, 18, pl. 9, figs 10-12; pl. 10, figs 11-14. — Bitner 1990: 135-138, text-figs 3, 4; pl. 3, figs 1-8; pl. 6, figs 1-7. — Taddei Ruggiero 1994: 208, pl. 3, figs 6-9.

MATERIAL EXAMINED. — One complete specimen from Algeria: LP-MNHN B.38665.

OCCURRENCE. — This species appears in the fossil record in the Eocene and lives now in the Mediterranean Sea and in the Lusitanian and Mauritanian regions of the Atlantic Ocean, as well as in the Caribbean Sea. Its depth range is from 5 to 896 m.

MEASUREMENTS. — Length 4.8 mm, width 5.7 mm, thickness 2.9 mm.

REMARKS

This rare micromorphic species is easily recognisable from its transversely oval outline, wide, straight hinge line, large triangular foramen, and a few broad ribs. It is very common and widespread in the Tertiary deposits throughout Europe. In the Miocene of the Paratethys it is one of the commonest species ( Dreger 1889; Meznerics 1943; Barczyk & Popiel-Barczyk 1977; Bitner 1990; Popiel-Barczyk & Barczyk 1990). In the Mediterranean region it is very common in the Miocene ( Davidson 1870; Sacco 1902; Julien 1940; Calzada 1978; Llompart & Calzada 1982) and the Pliocene ( Pajaud 1977; Gaetani & Saccà 1985a; Encinas 1992; Taddei Ruggiero 1994, 1996). Today this species is very common in the Mediterranean Sea ( Logan 1979), and also occurs in the eastern North Atlantic ( Brunton & Curry 1979; Logan 1983, 1988, 1993). Cooper (1977) also noted this species from the Caribbean Sea.

M. detruncata was recorded from Algeria by Fischer & Oehlert (1891), and Ficheur (1896b) reported the presence of the genus Argiope which is an earlier name for both Megathiris and Argyrotheca .

Figures

FIG. 6. — A-F, Terebratulina retusa (Linnaeus, 1758), Mustapha (Algiers), Algeria (LP-MNHN B.38659); A-D, ventral, dorsal, lateral and anterior views of complete specimen; E, F, dorsal views of complete specimens; F, SEM micrograph of juvenile specimen; G, H, Megathiris detruncata (Gmelin, 1790), SEM micrographs of ventral and dorsal views of complete specimen, Mustapha (Algiers), Algeria (LP-MNHN B.38665). Scale bars: 2 mm.