Division of Natural Science and Mathematics, Northeastern Oklahoma State University, Tahlequah, Oklahoma
An isolated tooth (RM2) assignable to Arctodus, the Pleistocene short-faced bear, was recovered from Gittin' Down Mountain Cave in January 1975, 6.5 miles west-southwest of Stilwell, Adair County, Oklahoma. Remains of the genus Arctodus have not been reported previously from Oklahoma.
Order Carnivora Bowdich, 1821
Family Ursidae Gray, 1825
Arctodus Leidy, 1854 cf. A. simus (Cope)
The tooth is excellently preserved and is approaching an advanced state of wear on the occlusal surface. The tooth is deposited at the University of Arkansas Museum, Fayetteville, Arkansas (Accession No. AU 75-839).
Two arctodont bears (Arctodus pristinus and A. simus) are recognized currently from the Pleistocene of North America (1, p. 4). A. pristinus, the smaller of the two species, has been identified from deposits of Yarmouth to Illinoian in age. A. simus remains occur in sites of early-middle Pleistocene (Kansan or Illinoian) to late Wisconsin age (1, p. 9). The present tooth has measurements as follows: anteroposterior diameter of crown, 29.5 mm; transverse diameter of crown, 19.5 mm. These measurements fall within the size range of A. simus when plotted on a width and length diagram of the second lower molars of the arctodont bears of North America (Figure 1).
The age of the find is uncertain. The site of the Oklahoma Arctodus cf. A. simus find is similar to the late Pleistocene Arctodus simus bearing deposits in Missouri and is assumed to be of similar age, probably Wisconsin.
Gittin' Down Mountain Cave contains over one mile of horizontal passage and six horizontal entrances. Numerous "bear beds" (shallow circular depressions in the sediment floor, some showing claw marks) occur in some passages of the cave. The tooth was found near a group of large "bear beds" approximately 350 feet from the nearest entrance. The relationship of "bear beds" and bears is not fully understood. Some "bear bed" deposits in Missouri have yielded skeletal materials of Arctodus, the Pleistocene black bear (Ursus americanus cf. U. a. amplidens, and the modern black bear (U. a. americanus). These mixed deposits are assumed to have accumulated over time as individual bears including Arctodus died during winter sleep (2, p. 89). It is hoped that more work in Oklahoma and surrounding states can provide data on this problem.
I wish to thank Skip Roy, Wesley, Arkansas, Dr. W. L. Manger, University of Arkansas, Fayetteville, and E. Grigsby, Northeastern Oklahoma State University, Tahlequah, Oklahoma, for their encourage-
ment and assistance. A special thanks goes to Dr. O. Hawksley, Central Missouri State University, Warrensburg, Missouri, for verification of identification, and Don Russell, owner of Gittin' Down Mountain Cave, for his permission to publish the find and for other assistance.
1. B. KURTÉN, Acta Zöol. Fenn. No. 117: 1-60 (1967).
2. O. HAWKSLEY, Bull. Natl. Speleol. Soc. 27(3): 77-92 (1965).