Coniacian (Late Cretaceous) echinoids from the southern Tethyan shelf (NE Algeria) with remarks on their palaeobiology and palaeobiogeography

Thirteen echinoid taxa are described from Coniacian marl-limestone alternations in three sections south and east of Djebel Metlili, on the southwestern margin of the Aures Mountains in northeastern Algeria. The biostratigraphic framework, based on ammonites and inoceramids, indicates an early to middle Coniacian age. The identified taxa include: Rachiosoma rectilineatum , Phymosoma tamarinense , P . cf. P. mansour , Gomphechinus meslei , Coenholectypus subcrassus, Parapygus coquandi , Petalobrissus trigonopygus , P . rimula , Hemiaster sp., and Mecaster fourneli . Three new species are described, Orthopsis metliliae sp. nov., Coenholectypus sulcatus sp. nov. and a new genus and species referred to the family Phymosomatoidae, Triboporus luluatus gen. et sp. nov. A large amount of well-documented material, comprising 579 specimens, was collected, with the fauna being dominated by the spatangoid Mecaster fourneli . At the genus level, the fauna exhibits characteristics typical of the Tethyan realm, and includes Rachiosoma , Gomphechinus , Mecaster , Parapygus and Petalobrissus . However, at the species level, most taxa are restricted to Algeria. Some are also found in adjacent countries such as Tunisia and Egypt. • Thirteen echinoid taxa from Coniacian strata in NE Algeria, composition typical of the Tethyan realm • Fauna dominated by the spatangoid Mecaster fourneli • Three new species and one new genus in Phymosomatoidae described • Most species endemic to Algeria