North-Central Section (44th Annual) and South-Central Section (44th Annual) Joint Meeting (11–13 April 2010)

Paper No. 7
Presentation Time: 1:30 PM-5:00 PM

THE TORYNOMMATIDAE GLAESSNER, 1980, IS POLYPHYLETIC


SCHWEITZER, Carrie E., Department of Geology, Kent State Univ at Stark, 6000 Frank Avenue NW, North Canton, OH 44720 and FELDMANN, Rodney M., Department of Geology, Kent State University, Kent, OH 44242, cschweit@kent.edu

The placement of Torynommatidae (Crustacea, Brachyura, Cyclodorippoidea), historically considered as primitive crabs, has been enigmatic since the family was named in 1980 by M. F. Glaessner. Inclusion of some of the genera and their placement is also problematic. Only four genera currently comprise the family, Torynomma, Dioratiopus, Binkhorstia, and Withersella. Examination of photographs or actual type material indicates that the group is polyphyletic and that the type genus, Torynomma, cannot be accommodated within the Cyclodorippoidea, in which the family has historically been placed. At least some of the constituent genera and species can probably be placed within the primitive Glaessneropsoidea, a superfamily that originated in the Late Jurassic. Other genera are under investigation, and it seems that each member of the family as currently construed may be placed into a different family! This reexamination is facilitated by modern interpretations of the sternum, abdomen, and orbital structures that were either unavailable or were not extensively used by workers in the past. Some of the genera may belong to more derived superfamilies, which could extend the geographic ranges of some of those groups, because the Torynommatidae is known from many Southern Hemisphere occurrences. Thus, it is anticipated that the revision of this family will dramatically change the systematic and biogeographic interpretation of the groups involved. Research supported by NSF EF-0531670 to Feldmann and Schweitzer.