2007 GSA Denver Annual Meeting (28–31 October 2007)

Paper No. 19
Presentation Time: 8:00 AM-12:00 PM

NEW PROPODIDAE (CRUSTACEA, DECAPOD) SPECIMENS FROM THE UPPER CRETACEOUS BEARPAW FORMATION


ROSS, Mike, 2614 Navarre Street, Casper, WY 82601, WAHL, William R., Paleontology, BigHorn Basin Foundation, 110 Carter Ranch RD, Thermopolis, WY 82443, EASON, Randy, 2300 E. 18th St. Casper, WY 82809, Casper, WY 82809 and BISHOP, Gale, Museum of Geology and Paleontology, South Dakota School of Mines and Technology, 501 East St. Joseph Street, Rapid City, SD 57701, wwahl2@aol.com

The discovery of two new propodid decapod specimens from the Bearpaw Shale Formation, one assigned to Ekalakia, and one representing a new species, expands the knowledge of the paleoecology of these taxa and of this portion of the last marine transgression of the Cretaceous Western Interior Seaway. Specimen WDC-Bps-003 was found preserved in a silty-limestone concretion in Niobrara, County, Wyoming within the Zone of Baculites grandis. It was found within the fossil hash and may represent the most complete specimen of the genus Ekalakia.

The second specimen (WDC-Bps-004) was collected within the Zone of Baculites baculus, Bearpaw Shale of Carter County, Montana and may represent a new genus and species. The genus Ekalakia can now be confidently placed with in the lower Maastrichtian (Zone of Baculites grandis) with a North American range of 69.5 =/- 0.37 million years ago. This find provides further evidence of a relict prosoponid decapod component in the Bearpaw Shale.