Abstract

The goniasterid starfish Comptoniaster michaelisi nom. nov., previously known under the names of Asterias schulzii or Stellaster schulzei, is re-examined in terms of nomenclature and taxonomic significance. The species was described and illustrated by Schulze in 1760 as Pentagonaster semilunatus, a name that referred to an extant species and did not conform to the rules of binomial nomenclature. The species-group name schulzii is invalid, so that the replacement name michaelisi is suggested. This early Late Cretaceous species can now be accommodated in the genus Comptoniaster. A lectotype for the species is designated (i.e., Schulze's figured specimen), reillustrated and described in detail herein. Additional data provided include other occurrences of the species in middle Turonian to middle Coniacian strata in the Saxonian, North Sudetic and Intrasudetic Cretaceous subbasins (Germany, Poland and Czech Republic). Eighteen moulds of well-preserved, articulated specimens were available for this study, and 14 of them are illustrated. The skeletal morphology of the species is reconstructed and single elements are described, characterising C. michaelisi as a medium-sized asteroid with an outer radius of up to 90 mm, 45-50 paired supero- and inferomarginals and an arm-to-disc ratio of 2.2-2.5. Striking morphological affinities with C. comptoni from the upper Albian-lower Cenomanian indicate that species as a possible ancestor of C. michaelisi. The species lived on shallow-marine, medium- to coarse-grained sandy sea floors. Taphonomic pathways suggest that both death and rapid burial of these asteroids were most likely induced by tempestite deposition.