Open Access Kent State (OAKS)

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.

Re-evaluation of the Prosopinae von Meyer, 1860 (sensu Glaessner, 1969) has resulted in placement of the included genera into two superfamilies, the Homolodromioidea Alcock, 1900, and Glaessneropsoidea Patrulius, 1959. The previously recognized Goniodromitidae Beurlen, 1932, and Tanidromitidae Schweitzer & Feldmann, 2008 [imprint 2007], are confirmed as belonging to the Homolodromioidea. New taxa recognized herein include four new families, Bucculentidae, Lecythocaridae, Longodromitidae, and Nodoprosopidae; four new genera, Abyssophthalmus, Bucculentum, Protuberosa, and Ver rucare inus; five new species, Bucculentum bachmayeri, Glaessneropsis myrmekia, G. tribulosa, Lecythocaris obesa, and Prosopon abbreviatum; and eight new combinations. Taxa are classified based upon a comprehensive array of characters including features of the orbits and rostrum; the nature and development of the carapace grooves; and the development of the dorsal and subdorsal carapace regions. A new term is defined, augenrest, for the concavity in the dorsal carapace or frontal margin of the carapace that lies distal to the orbit to house the eye. Recognition of two superfamilies for these taxa confirms the previous hypotheses of Feldmann et al. (2006), Schweitzer et al. (2007), and Schweitzer & Feldmann (2008 [imprint 2007]) that Jurassic Brachyura were much more diverse than previously recognized.

Laeviprosopon Glaessner, 1933, is a member of the Prosopidae von Meyer, 1860 within the Homolodromioidae. Members of the genus lack lineae homolicae, typical of the Homoloidea. Herein we expand the range of the genus to the Tithonian Ernstbrunn Limestone, from which it was previously unknown, and recognize two new species from that unit, Laeviprosopon grandicentrum and L. laculatum. Laeviprosopon thus far is known only from the Late Jurassic to Early Cretaceous of Europe, based upon seven species. Referral of Laeviprosopon to the Prosopidae does not expand the range of the family nor does it substantially change the diagnosis for it.

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.

Three new species from the Upper Jurassic (Tithonian) Ernstbrunn Limestone, Abyssophthalmus schultzi, Planoprosopon hystricosus, and P. rhathamingus, demonstrate the variability and diversity of the Longodromitidae Schweitzer & Feldmann, 2009. More importantly, the speciose nature of genera within the Longodromitidae and other families in Late Jurassic (Tithonian) rocks suggests that niche-partitioning may have been an important evolutionary driver early in the history of the Brachyura.

Evaluation of brachyuran decapod crustaceans exhibiting lineae homolicae from the Tithonian (Upper Jurassic) Ernstbrunn and Stramberk limestones in Austria and the Czech Republic has resulted in a major realignment of taxa within the Jurassic Homoloidea. A new family, Tithonohomolidae, is erected to accommodate Tithonohomola armata Blaschke, 1911, and T. tuberculata nov. spec. as well as a nov. gen., Tenuihomola, which comprises Tenuihomola longa Moericke, 1897, and T. ortwini nov. spec. A new genus and species, Doerflesia ornata, along with two species within the genus Gastrodorus are assigned to the Homolidae. Homolids appear to have evolved in warm, shallow, reefal environments in western and central Europe during the Late Jurassic.

Gabriella Collins et al., 2006, is herein restricted to five species, including two that are new, Gabriella anfracta and G. patula. The genus is referred to the Tanidromitidae Schweitzer & Feldmann, 2008 [imprint 2007] of Homolodromioidea. Other species previously referred to Gabriella are placed within Planoprosopon of the Longodromitidae Schweitzer & Feldmann, in press, in the Glaessneropsoidea Patrulius, 1959. One new species, Planoprosopon schweigerti, is named from the Late Jurassic (Tithonian) Ernstbrunn Limestone of Austria.

A single specimen of decapod crustacean, preserved in ventral view and compressed, represents a new genus and species of eryonid lobster, Wrangelleryon perates . The discovery in Lower Jurassic (Hettangian) sediments of the Sandilands Formation in British Columbia represents the first occurrence of Eryonidae in North America and reinforces a global distribution of the family in the Jurassic. The occurrence in British Columbia on the Wrangellia terrane supports the lower latitude setting in which the species lived.

The oldest confirmed brachyurans, referable to the Homolodromioidea and Glaessneropsoidea, are Early to Middle Jurassic in age. Geographically, all of the occurrences are in Europe, with one exception, in Tanzania.

Cycloprosopon Lőrenthey in Lőrenthey & Beurlen, 1929, is redefined and referred to the Goniodromitidae Beurlen, 1932. Four new species, Cycloprosopon conspicuum, C. devexum, C. octonarium, C. stenofrons, as well as two new combinations, Goniodromites transsylvanicus (Lőrenthey in Lőrenthey & Beurlen, 1929) and Eodromites dobrogea (Feldman, Lazǎr & Schweitzer, 2006), resulted from the revision. Representatives of Eodromites often retain wellcalcified elements of the appendages and lateral portions of the carapace, unusual among Jurassic brachyurans.