Late Cretaceous (Turonian – Coniacian) irregular echinoids of western Kazakhstan (Mangyshlak) and southern Poland (Opole)

Abstract

During the Late Cretaceous, both Mangyshlak and the Opole area were part of the North European Province, and irregular echinoid faunas during the Turonian and Coniacian in both areas were dominated by holasteroids and spatangoids, in particular by Plesiocorys, Echinocorys and Micraster.

Almost 1,000 specimens from both areas have been studied. Taxonomically more varied are the faunas from Mangyshlak (15 species in 6 genera); the Opole assemblages comprise 9 species in 3 genera. One species, Micraster (Micraster) praerogalae, a transitional form between Micraster (Micraster) cortestudinarium (GOLDFUSS) and Micraster (Micraster) rogalae NOWAK, is described as new. Micraster (Micraster) rogalae is markedly diachronous within the North European Province, first appearing in the late Coniacian in Mangyshlak and reaching central and western Europe during the late Early Santonian. A similar pattern is revealed by a large morphotype of Echinocorys ex gr. scutata LESKE.

Palaeoecological and actualistic data show the taxa studied to have been shallow infaunal (Catopygus), shallow epifaunal [Conulus (Conulus) subrotundus], deeper infaunal [Micraster (Micraster)], deeper semi-infaunal [Micraster (Gibbaster), Plesiocorys (Sternotaxis) plana], deeper epifaunal [Echinocorys, Plesiocorys (Plesiocorys) placenta], and deeper infaunal (Hemiaster).

Echinoid bioevents described originally from the Salzgitter-Salder section (Lower Saxony, Germany) can also be recognised in the Opole area, but not further afield in Mangyshlak.