Mimimitoceras mina, Korn & Weyer, 2023

Korn, Dieter & Weyer, Dieter, 2023, The ammonoids from the Gattendorfia Limestone of Oberrödinghausen (Early Carboniferous; Rhenish Mountains, Germany), European Journal of Taxonomy 882, pp. 1-230 : 27-28

Mimimitoceras mina sp. nov.

urn:lsid:zoobank.org:act:BF32EC27-3412-4B7A-83E0-5B5A5097B3F0

Tables 6–7

Mimimitoceras hoennense – Bockwinkel & Ebbighausen 2006: 93, text-figs 6, 7c–d. Mimimitoceras varicosum – Bockwinkel & Ebbighausen 2006: 94, text-figs 7a–b, 8.

Diagnosis

Species of Mimimitoceras with thinly globular and involute conch at 5 mm dm (ww/dm ~0.85; uw/ dm ~0.03); thinly pachyconic and involute conch at 15 mm dm (ww/dm ~0.70; uw/dm ~0.01). Whorl profile at 15 mm dm weakly depressed (ww/wh ~1.25); coiling rate low (WER ~1.65). Venter broadly rounded throughout ontogeny. Prominent internal shell thickenings with concavo-convex course. Suture line with very narrow, lanceolate external lobe and very narrow, symmetric, V-shaped adventive lobe.

Etymology

Acronym for Mimimitoceras from North Africa.

Material examined

Holotype

MOROCCO • Anti-Atlas , Mfis near Taouz , bed 9; Bockwinkel & Ebbighausen Coll.; illustrated by Bockwinkel & Ebbighausen (2006: text-fig. 7a–b); MB.C. 3824.2.

Paratypes

MOROCCO • 30 specimens; Anti-Atlas , Mfis near Taouz , bed 9; Bockwinkel & Ebbighausen Coll.; MB.C.3823.1–19, MB.C.3824.1, MB.C. 3824.3–12 .

Description

The species newly described here has been treated in detail by Bockwinkel & Ebbighausen (2006), so reference can be made here to that description.

Remarks

The material described here as the new species Mimimitoceras mina sp. nov. was placed in the two species M. hoennense and M. varicosum by Bockwinkel & Ebbighausen (2006). In fact, however, the differences within this material are so small that a species separation can hardly be justified.

Mimimitoceras mina sp. nov. resembles M. perditum sp. nov. in conch shape, but the whorl profile shows convergent flanks in M. mina , which are broadly rounded in M. perditum ; the widest part of the conch is near the umbilicus in M. mina and near the middle of the flanks in M. perditum . Another difference lies in the course of the constrictions; these run almost linearly in M. perditum , but with a distinct lateral sinus and ventral sinus in M. mina .