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THE OLDEST KNOWN REPTILE, 

 EOSAURAVUS COPEI WILLISTON 



By FRANK E. PEABODY 



Department of Zoology 



University of California 



Los Angeles, Calif. 



(With One Plate) 



One of the most tantalizing examples of Carboniferous tetrapods 

 is the posterior part of a small skeleton from Linton, Ohio, described 

 by Cope in 1897 as the earliest known reptile. Some 60 years later, and 

 after many taxonomic vicissitudes, the specimen seems in danger of 

 slipping into obscurity among the microsaur Amphibia. Meanwhile 

 no more reptiles have been found at Linton or in earlier horizons. 1 

 Various students have described Cope's specimen, but most have 

 tended to discount its importance because the anterior part of the 

 skeleton, including the skull, is missing, and have tended to accept the 

 early descriptions with little question. Present high interest in the 

 origin of reptiles during the Carboniferous prompted a restudy of 

 Cope's historic specimen. It was found that strong lighting from a 

 very low angle, and directed from various positions, revealed much 

 new detail that can be demonstrated by photographic enlargements. 

 The result is a new interpretation, particularly of the vertebrae and 

 tarsus, which reaffirms the reptilian affinities of the specimen and 

 furthermore strongly suggests a captorhinomorph relationship. 



I am indebted to Dr. Peter P. Vaughn of the United States National 

 Museum for permission to borrow Cope's specimen, and to Miss 

 Madeline M. Peabody, my sister, for assistance with the illustrations. 



1 [Cephalerpeton ventriarmatum, apparently a captorhinomorph reptile (see 

 Gregory, 1950), is known from the nodule beds at Mazon Creek, 111., which 

 represent a somewhat earlier horizon (but still within the Allegheny series). 

 —Ed.] 



SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 139, NO. 1 



