The genus Cyclothyreus Remeš, 1895, is comprised of nine species, four of which are new: Cyclothyreus cardiacus, C. divaricatus, C. quadrophthalmus, and C. strangus. Cyclothyreus is for now placed within the Dynomenidae sensu lato, recognizing that it cannot be accommodated within any of the existing subfamilies, or for that matter, within any existing family within the Dromioidea. All known species of Cyclothyreus are Tithonian in age and are known from localities in central and eastern Europe.
New crabs (Decapoda: Brachyura: Prosopidae) from Jurassic (Oxfordian) Sponge Bioherms of Dobrogea, Romania01/01/2006
A previously undescribed fauna of primitive brachyurans of the family Prosopidae is reported from sponge bioherms in eastern Romania. One new species, Cycloprosopon dobrogea, and several other forms, constitute the brachyuran fauna. The sponge bioherms, which attain a height of 30 meters, have yielded an abundant, but not overly diverse, array of benthic invertebrates. Some of the brachyuran specimens bear epibionts, unusual in the fossil record of the Decapoda. The constitution of several genera within the Prosopidae is herein summarized in order to facilitate further work on the family within the context of modern systematic methods.