Stroboceras sp.

Korn, Dieter & Klug, Christian, 2023, Early Carboniferous coiled nautiloids from the Anti-Atlas (Morocco), European Journal of Taxonomy 885, pp. 156-194 : 162-163

Stroboceras sp.

Fig. 5

Material examined

MOROCCO • 1 specimen; Anti-Atlas, region south-west of Rissani ; basal Mougoui Ayoun Formation; Karaoui Coll.; PIMUZ 39512 .

Description

The single specimen PIMUZ 39512 has a conch diameter of 42 mm and is embedded in a siderite nodule ( Fig. 5 ). Less than a whorl of the evolute conch (uw/dm ~0.47 to 0.54) is available for study; this shows an angular and depressed whorl profile (ww/wh ~1.40) with flattened, weakly convergent flanks and a flattened, slightly concave venter. The ventrolateral shoulder and umbilical margin are subangular. There are six longitudinal ridges on the flank, the outer ones forming the umbilical margin and the ventrolateral shoulder, respectively. Additionally, there are two ridges on the outside of each venter, followed by some much finer lines towards the plane of symmetry. A slight granulation is produced on the ridges by the growth lines, which are somewhat reinforced here.

Figures

Fig. 5.Stroboceras sp., specimen PIMUZ 39512 (Karaoui Coll.)from south-eastof Rissani; reconstruction of apertural view, lateral and ventral views. Scale bar units =1 mm.