Becanites africanus, Korn & Bockwinkel & Ebbighausen & Klug, 2003

Korn, Dieter, Bockwinkel, Jürgen, Ebbighausen, Volker & Klug, Christian, 2003, Palaeobiogeographic and evolutionary meaning of an early Late Tournaisian ammonoid fauna from the Tafilalt of Morocco, Acta Palaeontologica Polonica 48 (1), pp. 71-92 : 77

publication ID	https://doi.org/ 10.5281/zenodo.13272527
persistent identifier	https://treatment.plazi.org/id/03BE87DE-5A76-FFC0-FFB2-F98476CCFC3C
treatment provided by	Felipe
scientific name	Becanites africanus
status	sp. nov.

Treatment

Becanites africanus View in CoL sp. nov.

Figs. 9 View Fig , 10 View Fig , 11A–C View Fig .

Derivation of name: Afterthecontinentfromwherethespecimenswere collected.

Holotype: Specimen MB.C.3901 (coll. Bockwinkel), Fig. 11A View Fig .

Type locality and horizon: Taouz, Jebel Ouaoufilal, locality A east of Ksar Bouhamed (Tafilalt, Morocco); early Late Tournaisian.

Material.—182 mostly fragmentary specimens, 5 to 20 mm in diameter.

Diagnosis.— Becanites with discoidal conch (ww/dm 0.35). Umbilicus wide at 8 mm diameter (uw/dm 0.45 to 0,50) and moderately wide at 15 mm diameter (uw/dm 0.40). Flanks and venter broadly rounded. Suture line with large and deep,

pouchedexternallobe,lanceolateandpouchedadventiveand lateral lobe on the flank.

Description.—All the specimens are similar in their conch geometry and ratios, but juveniles are more evolute than larger specimens ( Fig. 9 View Fig ). Juveniles have a circular whorl cross section, and adults display an oval, slightly compressed shape. The relative apertural height increases during ontogeny, resulting in an acceleration of the whorl expansion rate from 1.90 at 5 mm to 2.50 at 18 mm conch diameter. In this respect, B. africanus has an ontogeny that is typical for the prolecanitids.

The surface of the steinkern is smooth without any indication of ornament. It can therefore be assumed that the shell is very weakly ornamented.

The suture line is characteristic for Becanites ( Fig. 10 View Fig ), but the external lobe, as seen in paratype MB.C.3909, is extremely large and bulb−shaped, as known only from stratigraphically younger and more derived genera such as Michiganites Ruzhencev, 1962 and Prolecanites Mojsisovics, 1882 . The adventive lobe and the lateral lobe, which are both located on the flank, are also pouched and pointed at the bottom.

Dimensions.—(in mm). Comparisons.— B. africanus sp. nov. is, by its large and strongly pouched external lobe, different from the other species of the genus: B. algarbiensis ( Pruvost, 1914) , B. abnobensis ( Vöhringer, 1960) , B. geigenensis ( Schmidt, 1925) , B. gurleyi ( Smith, 1903) , B. sernageominus ( House, 1996) , and B. nuraensis ( Librovitch, 1940) . Furthermore, B. algarbiensis , B. sernageominus and B. geigenensis are more widely umbilicate (uw/dm 0.50) than B. africanus sp. nov.