Fig. 4 in Thyasirid bivalves from Cretaceous and Paleogene cold seeps

Fig. 4. Thyasirid bivalve Conchocele townsendi (White, 1890) from Maastrichtian cold seep carbonates of Seymour Island, James Ross Basin, Antarctica. A. NRM Mo 1560; a complete shell in right (A1) and left (A2) lateral view, showing outline and fine commarginal ornament; in anterior view (A3), showing two ridges running from the umbo towards the anteroventral angle; in dorsal view (A4), showing narrow and sharp posterior sulcus and posterior fold and weak furrow possibly representing accessorial ligament attachment surface. B. NRM Mo 1552; an internal mold in left lateral view with fragments of the shell adhering to the anterior and umbonal area (B1) and with outline of the anterior adductor muscle scar visible (B2).