Rineceras sp. 2

Korn, Dieter & Klug, Christian, 2023, Early Carboniferous coiled nautiloids from the Anti-Atlas (Morocco), European Journal of Taxonomy 885, pp. 156-194 : 161

Rineceras sp. 2

Fig. 4B

Material examined

MOROCCO • 1 specimen; Anti-Atlas, region south-west of Rissani ; basal Mougoui Ayoun Formation; Karaoui Coll.; PIMUZ 39510 .

Description

Specimen PIMUZ 39510 is mostly an internal mould ( Fig. 4B ), which has a conch diameter of 42.5 mm and is 14 mm wide with an umbilicus 20.5 mm wide (uw/dm ~ 0.40). The body chamber and last three chambers are partly embedded in a sideritic nodule. It has a depressed rounded-triangular whorl profile with flattened venter. Flanks and venter bear longitudinal equidistant ridges (5 on the umbilical wall, 3 to 4 on the flank and 2 between the ventrolateral ridges); a granulation is visible at some places at the crossing points of spiral ridges and growth lines.

Figures

Fig. 4.Specimens of Rineceras Hyatt, 1893.A. Rineceras sp. 1;specimen MB.C.31293.1 (Ebbighausen & Korn 2004 Coll.) from Gara el Itima N; ventral and lateral views, and whorl profile. B. Rineceras sp. 2; specimen PIMUZ 39510 (Karaoui Coll.) from south-east of Rissani; lateral and ventral views. Scale bar units= 1 mm.