REEVALUATING PROSOPID DECAPOD CRUSTACEANS: THE ROOTSTOCK OF THE TRUE CRABS

The dromiacean family Prosopidae von Meyer, 1860, sensu Glaessner, 1969, had its origin in the Middle Jurassic and is currently recognized as one of the oldest clades within the Brachyura, the true crabs. For this reason, discussions of the phylogeny of the Brachyura hinge upon this family. However, our examination of type specimens of species of many of the included genera, as well as study of 19th and early 20th century collections of other specimens, confirm that the generic assignments in more recent studies must be re-evaluated. The original concepts of the various genera as originally conceived by their authors have not been consistently applied, owing to reliance upon inadequate illustrations in the literature, incompletely prepared specimens, and application of morphological characters that are not adequate for distinguishing among these taxa. Recent collection of several hundred specimens of prosopid crabs from Jurassic sponge and coral reef exposures within the Carpathian Mountains in Romania and Poland, coupled with our study of the major collections of the Prosopidae housed in museums in Germany, Austria, and Poland, have led to the conclusion that several previously undescribed morphological features document the polyphyletic nature of the family. Application of these characters will provide a new framework within which to arrange taxa, and preliminary analysis suggests that a much broader array of higher-level taxa are embraced in what is currently considered the Prosopidae. In addition, these organisms may well comprise the rootstock of several lineages within the early radiation of the crabs. This work was supported by NSF grants EF 0531670 and INT 0313606 to Feldmann and Schweitzer.