Gryphus capensis Jackson, 1952

Bitner, Maria Aleksandra & Logan, Alan, 2016, Recent Brachiopoda from the Mozambique-Madagascar area, western Indian Ocean, Zoosystema 38 (1), pp. 5-41 : 12-13

Gryphus capensis Jackson, 1952

( Fig. 6 F-J)

Gryphus capensis Jackson, 1952: 16-18 , pl. 1, figs 10-13.

MATERIAL EXAMINED. — North-West Madagascar. MIRIKY, stn DW 3196, 1 bivalved open specimen, slightly broken ventral valve.

DEPTH RANGE. — 238- 249 m.

MEASUREMENTS. — Length of dorsal valve 11.0 mm, width 10.1 mm.

REMARKS

There are five species of Gryphus recorded from modern seas, of which the best known is the type species G. vitreus (Born, 1778) from the Mediterranean Sea ( Logan 1979). The only representative of this genus from the Indian Ocean is G. capensis which Jackson (1952) described from the South coast of South Africa. Hiller (1991, 1994) has also recorded it from the same general region. The sole specimen of G. capensis obtained in this study from North-West Madagascar differs slightly from the type species in that the transverse band of the loop has a more pronounced ventral arching at the centre ( Fig. 6J ). It is, however, consistent with the specimens described by Jackson (1952). The shell is small, elongate oval, ventribiconvex. The foramen is large, oval with a short, excavate pedicle collar. The teeth are short but wide with very weak swollen bases. The cardinal process is small, whereas the triangular outer hinge plates are wide and concave, bordered by crural bases. The loop is short with parallel descending branches and a broad transverse band. The shell is composed of three layers with a relatively thin tertiary prismatic layer ( Fig. 6H ).

Figures

FIG. 6. — A-E, Xenobrochus africanus (Cooper, 1973), Mozambique Channel, Inhambane transect, MAINBAZA, stn CP 3143, 264-277 m (MNHN IB-2013-50): A, B, dorsal view of complete specimen and enlargement of the umbonal part to show details of the beak (B); C, inner view of ventral valve; D, E, inner view of dorsal valve (C), and enlargement of posterior part (E) to show details of brachial skeleton; F-J, Gryphus capensis Jackson, 1952, North-West Madagascar, West of Cap d’Ambre, MIRIKY,stn DW 3196, 238-249 m (MNHN IB-2013-43): F-H, inner view of ventral valve (F), enlargement of posterior part (G) to show teeth and symphytium, and broken transverse section, showing secondary fibres and prims of the tertiary layer (top), characteristic for the genus, I, J, inner view of dorsal valve, and enlargement of posterior part (J) to show details of cardinalia and loop. All SEMs. Scale bars: A, C, D, F, I, 2 mm; B, E, G, J, 1 mm; H, 50 µm.