Remains of decapod crustaceans from the late Cenomanian and early Turonian of the Czech Republic mistakenly assigned to crayfishes (Astacoidea)

Abstract Two species of fossil crustaceans from the Czech Republic are assigned to AstacusFabricius, 1775, a European crayfish: A. laevissimusFritsch & Kafka, 1887 and A. cenomanensisFritsch & Kafka, 1887. Both come from marine sediments, making doubtful their assignment to crayfishes. Specimens assigned to Astacus laevissimus correspond in fact to propodi of etyoid brachyurans. The type material of A. cenomanensis is heterogeneous, comprising fragmentary ctenochelid (Thalassinidea) propodi and isolated cheliped fingers of etyoid crabs. None of the two species belong to crayfishes. Since the studied cheliped material is too fragmentary and poorly preserved to be attributed confidently on species or genus level, A. laevissimus and A. cenomanensis are considered nomina dubia.