o /\(/xl u ur APR 2 11977 B R E V I O R A^ Miuseiim of Comparative Zoology us ISSN 0006-9698 CambridCxE, Mass. 8 April 1976 Number 436 STUPENDEMYS GEOGRAPHICUS, THE WORLD'S LARGEST TURTLE Roger Conant Wood^ Abstract: Stupendemys geographicus, a gigantic fossil pelomedusid turtle from the late Tertiary (Huayquerian) Urumaco Formation of northern Venezuela is described. Stupendemys was evidently a highly aquatic form. Whether it was a fresh water or marine turtle, however, cannot be determined with certainty on the present evidence. One or perhaps even both pairs of limbs may have been modified into flippers, and the head may not have been fully retractable in the usual pleurodiran manner. Comparisons with records of other enormous chelonians reveal that the carapace of Stupen-demys is larger than that of any other turtle, fossil or recent. INTRODUCTION Paleontologists are occasionally fortunate enough to make totally unexpected discoveries. Such was the case during the summer of 1972, when a Harvard paleontological expedition working in late Tertiary deposits of northern Venezuela un-earthed the remains of several huge fossil turtles. These cer-tainly attained greater size than any other extinct chelonians yet known; they also appear to be larger than any living ones and hence the largest turtles that ever existed. The purpose of this paper is to describe these gargantuan creatures. The following abbreviations are used : AMNH: American Museum of Natural History, herpetological collections MCNC: Museo de Ciencias Naturales, Caracas MCZ: Museum of Comparative Zoology: (H), herpetological collections; (P), paleontological collections PU: Geology Museum, Princeton University iFaculty of Science and Mathematics, Stockton State College, Pomona, N. J. 08240.
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