B K -i ^ —S. COMP. ZOOL-MAf? J 8 1985 ro ff A Mseum of Comparative Zoology us ISSN 0006-9698 Cambridge, Mass. 29 April 1983 Number 474 RVTHIROMIA ELCOBRIENSIS, A NEW PELYCOSAUR FROM EL COBRE CANYON, NEW MEXICO David A. Eberth' and Donald Brinkman^ Abstract. Riithiioniia elcuhrien.si.s. a new genus and species of pelycosaur from the Permo-Carbonilerous redbeds of El Cobre Canyon. New Mexico, is based upon an articulated portion ot the vertebral column, partial appendicular skeleton, and associated vertebral and cranial fragments. Ruthirumia is tentatively included within the Varanopseidae on the basis of postcranial characters, it is distinguished from all other varanopseids by its larger size, pinched-in lumbar centra, and massively developed delto-pectoral crest. INTRODUCTION The Permo-Carboniferous, Cutler formation redbeds of El Cobre Canyon, New Mexico, have yielded a unique assemblage of fossil tetrapods. El Cobre Canyon, near Abiquiu, New Mexico, is a large box canyon that has been sporadically prospected by collectors and paleontologists since the late 1870's. The fossil fauna and flora, known from both the canyon walls and floor, was most recently reviewed by Fracasso (1980). In 1965 A. Lewis and S. Olsen collected the larger part of the postcranial skeleton and disarticulated cranial fragments of a 'Department of Geologs. Universit\ of I oronto. Toronto, Ontario, Canada, M5T IR7. -Museum of Comparati\c Zoolog\, Harvard University, Cambridge, Massachusetts 02138. Present Address: lyrrell Museum of Paleontology. Bo.\ 7500. Drumheller. Alberta. Canada. lOJ OYO.