20 C. C. Bentley, J. L. Knight, and M. A. Knoll 



broader distal end and are considerably larger than S. tridecemlineatus. 

 The humerus of S. franklinii is significantly larger (2x) and varies 

 morphologically from S. tridecemlineatus. The fossil humerus is in- 

 distinguishable from that of Spermophilus tridecemlineatus and given 

 geographical and temporal considerations is assigned to this species 

 (Fig. 3). 



The thirteen-lined ground squirrel has a modern range reaching 

 into central Canada, south into eastern Utah and central Texas, and 

 eastward through the Midwest into Ohio (Hall 1981). The fossil 

 specimen from the Ardis site is about 1,000 km southeast of its present 

 day distribution. S. tridecemlineatus inhabits shortgrass prairies and 

 does not occur in forested areas (Kurten and Anderson 1980). Clark's 

 Cave and Natural Chimneys, Virginia, and Baker Bluff Cave, eastern 

 Tennessee, are the closest fossil localities containing remains of S. 

 tridecemlineatus. Martin and Webb (1974) reported Spermophilus sp. 

 from Haile 14A in Florida, which is the most southeastern report of 

 this genus. This ground squirrel's presence in the East has been inter- 

 preted as indicating parkland or semi-prairie conditions (Guilday et 

 al. 1977, Kurten and Anderson 1980). 



This is the first fossil record of Spermophilus tridecemlineatus 

 from South Carolina. 



Family Castoridae 



Castor canadensis - Beaver 



Material: 1 left M3 (.176); 1 partial incisor (.177); 1 left M2 (.178); 



1 radius (.180); 1 tibio-fibula distal end (.179); 1 metatarsal (.193); 



1 phalanx (.181); 1 thoracic vertebra (.182); 1 caudal vertebra (.183). 



Remarks: The beaver is found throughout most of North America 

 except for southern peninsular Florida, the arid regions in the Southwest, 

 and along Arctic shorelines (Kurten and Anderson 1980). The presence 

 of this semiaquatic species in the Ardis local fauna indicates the 

 presence of a nearby wooded, permanent body of water. 



Presence in the South Carolina fossil record from Edisto Beach 

 was first established by Roth and Laerm (1980), although they state 

 that the single postcranial element may be modern. 



Family Muridae 



Subfamily Arvicolinae 



Ondatra zibethicus - Muskrat 



Material: 1 complete skull (.27); 2 partial skulls (1 USNM), (1 UF); 



4 parietals (.28-. 30), (1 USNM); both maxillaries and palate missing 



