Ephippioceras pygops sp. nov.

urn:lsid:zoobank.org:act: 498203A9-1F48-441C-B413-35C683103AE1

Fig. 18; Table 8

Diagnosis

Species of Ephippioceras with thickly pachyconic, subinvolute conch, whorl profile moderately depressed (ww/wh ~1.60) with broadly rounded venter and rounded umbilical margin. Impressed zone deep (IZR ~ 0.37). Suture line with high, subangular ventral saddle.

Etymology

Named after the brachiopod genus Pygope, because of the shape of the septal surface.

Material examined

Holotype MOROCCO • Anti-Atlas, east of Gara el Itima, 36 km east-northeast of Taouz; uppermost Zrigat Formation; Ebbighausen & Korn 2004 Coll.; illustrated in Fig. 18; MB.C.31292.

Description

Specimen MB.C.31292 (Fig. 18A) is a fragment of a specimen with a phragmocone diameter of about 80 mm. The whorl profile is crescent-shaped with a broadly rounded venter that continues onto the flanks, a rounded umbilical margin and a convex umbilical wall. The whorl section is moderately depressed (ww/wh=1.60) and the whorl embraces the preceding one to a rather high degree (IZR =0.37). The septal surface shows the striking bilobate shape with a median ridge that separates the septum in two concave bulges. The suture line forms a narrow, subangular saddle on the venter, a wide, broadly rounded lobe on the flank and another smaller lobe on the umbilical wall (Fig. 18C).

Remarks

Ephippioceras pygops sp. nov. has a far less depressed whorl profile when compared with the other species of the genus. While the ww/wh ratio is only 1.60 in E. pygops, it is close to a value of 2.00 or even higher in E. clitellarium and E. sphaericum (Shimansky 1967) . In E. bilobatum, E. ferratum and E. verneuili, the whorl overlap is much lower (IZR ~ 0.20) than in E. pygops (IZR ~0.37). Ephippioceras spirale is difficult to compare because of the small size (19 mm dm) of the only one specimen.