Re-description of the lectotype of “Spatangus cortestudinarium Goldfuss, 1829” (Late Cretaceous) and its implications for the phylogeography of Micraster (Spatangoida, Echinoidea)

Abstract

A detailed re-description of the lectotype of “Spatangus cortestudinarium Goldfuss, 1829” [currently used as Micraster cortestudinarium (Goldfuss, 1829)], (designated by Stokes 1975), was undertaken and compared to previous taxonomic interpretations of this species. Comparisons with additional known material from across Europe allowed the more reliable identification of the provenance of the type specimen than previously postulated, which most likely originates from the Chalk of the Anglo-Paris Basin (southern England, northern France). Hitherto it was frequently accepted that the geographic distribution of M. cortestudinarium occurred in large parts of Europe and western Asia. Accordingly, the evolutionary succession (including M. cortestudinarium), recognised in the Anglo-Paris-Basin, was assumed to be also traceable outside of the Anglo-Paris Basin. The re-assessment of M. cortestudinarium, resulting in a distribution restricted to the Anglo-Paris Basin, has implementations for the biogeography and interpretation of the evolution of Micraster. The evolution within Micraster must thus have occurred differently in the various Cretaceous realms and been more diverse than thought so far.