Ostrea sp. A

Musavu Moussavou, Benjamin, 2017, Systematics, palaeoecology and taphonomy of Turonian oysters from the northern Gabon Coastal Basin, Geodiversitas 39 (2), pp. 213-224 : 220

Ostrea sp. A

( Fig. 4 S-U)

MATERIAL. — 10 specimens (MDG/LBV/Lm-15.1 to Lm-15.10).

OCCURRENCE. — Turonian of Gabon (this study).

DESCRIPTION

Shell is large, inequivalve, inequilateral, elongated, subtrigonal to suborbicular in outline. Umbo is small and prominent. Anterior and ventral margin are rounded. Posterior margin straight is angulated toward ventral margin. Attachment area is small. LV is slightly inflated. RV is flat. Ornamentation of LV consisting of numerous radial subacute ribs. This ribs start at the umbonal area, occasionally carrying small spines near ventral margin, and crossed by growth lamellae at irregular intervals. RV is ornamented by concentric fine growth squamae.

REMARK

Ostrea sp. A differs from Ostrea lateralis Nilsson, 1827 in having an angulated posterior margin without fold.

Figures

FIG. 4. — A-D, Ostrea sp. D: A, B, MDG/LBV/Lm-33.1; C, D, MDG/LBV/Lm-33.2; E, Ostrea sp. C MDG/LBV/Lm-32.1; F, Gyrostrea sp. B MDG/LBV/Lm-14; G-N, Gyrostrea delettrei (Coquand,1862);G, H, MDG/LBV/Lm-12.1;I, J, MDG/LBV/Lm-12.2;K, L, MDG/LBV/Lm-12.3,M-N.MDG/LBV/Lm-12.4;O-R, Ostrea sp.B;O, P, MDG/LBV/Lm-31.1;Q, R, MDG/LBV/Lm-31.2;S-U, Ostrea sp.A,S-T.MDG/LBV/Lm-15.1;U, MDG/LBV/Lm-15.2.Scale bar:1 cm.