THE DAKOTICANCRIDAE (DECAPODA, BRACHYURA) FROM THE LATE CRETACEOUS OFNORTH-AMERICA AND MEXICO

The podotrematous crab family Dakoticancridae includes four genera: Da koticancer Rathbun, Tetracarcinus Weller, Avitelmessus Rathbun, and Se orsus Bishop, all known solely from the Late Cretaceous of North Ameri ca. Lathelicocarcinus Bishop, originally referred to the family, must be reassigned. Fine derails of anatomy, preserved on specimens of D. o veranus Rathbun and A. grapsoideus Rathbun, permit description of geni tal openings and interpretation of functional morphology of appendages . Although one species, D. australis Rathbun, has been found associate d with burrow structures, all were probably vagrant epifaunal animals on fine- to medium-grained siliciclastic substrata. Food was probably obtained by generalized low-level predation and scavenging. Results of a cladistic analysis are consistent with the stratigraphic data sugge sting that T. subquadrata Weller is nearest the rootstock of the famil y and that other taxa within the family are derived from it.