Dynomenid crabs (Decapoda, Brachyura) and stalked barnacles (Cirripedia, Scalpelliformes) from upper Cenomanian-lower Turonian nearshore, shallowwater strata in the Bohemian Cretaceous Basin, Czech Republic
Abstrakt
Crustacea (dynomenid crabs and cirripedes) from the upper Cenomanian-lower Turonian nearshore, shallow-water bioclastic limestones to marly siltstones found along the southern and eastern margins of the Bohemian Cretaceous Basin (BCB) are described. Crabs are rather rare in this area, and mostly restricted to fragmentary pereiopods, i.e., isolated claws or dactyli.
In view of the confused taxonomy of isolated claws, their proper identity could not be determined; they were mostly referred to the necrocarcinid genus Necrocarcinus Bell, 1863. A recent re-examination of material deposited in the collections of the National Museum (Národní Muzeum, Prague), and of new finds, has revealed that all allegedly necrocarcinid pereiopods and nearly all carapaces from these shallow-water strata actually belong to the dynomenid Graptocarcinus Roemer, 1887 (carapaces) and the 'form genus' Roemerus Bishop, 1983 (isolated claws).
Here we present a summary report of occurrence of these dynomenid genera in the BCB. Cirripedes are more abundant, yet all available material is in the form of disarticulated, isolated capitular plates, which is typical for almost all Mesozoic thoracicans.
More than 400 capitular plates of stalked barnacles have been discovered in sieve residues during the last decade. A study of newly recovered specimens, together with a revision of material contained in museum collections, has resulted in the description of a new species of the genus Zeugmatolepas Withers, 1913 and confirmation of the occurrence of 'Scillaelepas' conica (Reuss, 1844), Titanolepas tuberculata (Darwin, 1851), Smilium? parvulum (Withers, 1914), Cretiscalpellum glabrum (Roemer, 1841), C. striatum (Darwin, 1851) and Arcoscalpellum angustatum (Geinitz, 1843).