Latest early Toarcian and middle Toarcian brachiopods (Rhynchonellida) from the Central Unit of the South Riffian Ridges (northern Morocco)

Uppermost lower Toarcian and middle Toarcian stratigraphic succession of the Central Unit of the South Riffian Ridges (Morocco), particularly in the El Heitouf and Sned sections, are rich in benthic macrofauna (gastropods, bivalves and brachiopods). Nine brachiopod species of the order Rhynchonellida belonging to six genera have been listed, which are: Gibbirhynchia reyi, Homoeorhynchia batalleri, Quadratirhynchia vasconcellosi, Pseudogibbirhynchia jurensis, Rhynchonelloidella marini, Soaresirhynchia babtisrensis, Soaresirhynchia bouchardi, Soaresirhynchia sp. and Soaresirhynchia tamazirta. H. batalleri, highly abundant, is represented by five individual groups, which have been distinguished based on the number of ribs (two to six) on the dorsal median fold. Each group is represented by juvenile to adult specimens representing successive stages of ontogenic development. Listed species, described and illustrated herein, complete previous data on this fossil group from the studied area. Most of these species are common to several marginal basins of northern and southern margins of the western Tethys Ocean, particularly northern Africa and southwestern Europe.

Automated summary

The Uppermost lower Toarcian and middle Toarcian stratigraphic succession in the Central Unit of the South Riffian Ridges in Morocco are rich in benthic macrofauna, particularly brachiopod species. One abundant species, H. batalleri, is distinguished by the number of ribs on the dorsal median fold and has five individual groups representing different ontogenic stages. These species are common to various marginal basins of the western Tethys Ocean.