Middle Devonian brachiopods from northern Maïder (eastern Anti-Atlas, Morocco)

Abstract

Sixty brachiopod species are reported from the Taboumakhlouf Formation (upper Eifelian) and the Bou Dib Formation (upper Eifelian to Givetian) of Jbel Issoumour, northern Maïder, Anti-Atlas, Morocco, on the basis of collections made by Volker Ebbighausen. The stratigraphy is based on reports of co-occurring trilobite assemblages. The relatively diversified fauna pre-dates the Taghanic event and is dominated in terms of diversity by atrypides and rhynchonellides (11 species each); other frequent species include Poloniproductus varians, Aulacella prisca, Tyersella tetragona, Schizophoria schnuri, Athyris ex gr. concentrica, Yeothyris? sinuata, and Thomasaria simplex. Spinatrypa ennigaldinannae Halamski and Baliński sp. nov. from the upper Eifelian is characterised by a transverse shell, typically 16–18 mm wide with 19–22 ribs. Prodavidsonia ebbigahuseni Halamski and Baliński sp. nov. differs from other representatives of the genus in having nearly flat shells. Eressella coronata Halamski and Baliński, nom. nov. is proposed as a replacement name for the permanently invalid Rhynchonella coronata Kayser, 1871 (non R. coronata Moore, 1861). Thomasaria simplex is documented as being a particularly variable species (costation, tongue, interarea position), so its broad taxonomic treatment is favoured. The brachiopod fauna shows distinct Rhenish affinities (numerous species in common with the Eifel and the Holy Cross Mountains) like the coeval fauna from southern Maïder, described previously. The Middle Devonian brachiopod fauna from the whole Maïder (north, described here and south, described previously) totals 87 species.