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



The muskrat is found throughout much of North America, including 

 all of South Carolina. This is the most aquatic of the microtine rodents 

 and is usually found in close proximity to fresh or brackish waters. 



This is the first fossil record of this species from South Carolina. 



Neofiber alleni - Round-tailed Muskrat (Florida Water Rat) 

 Material: 1 right Ml (.153); 1 fragmentary molar (.154). 



Remarks: N. alleni is endemic to Florida and southernmost Georgia, 

 and its northward limits may be maintained by aridity and cold tem- 

 peratures (Frazier 1977). It is not currently sympatric with O. zibethicus. 



The enamel above the jaw line on the partial molar appears to 

 be chemically etched or corroded. This may be due to the ingestion of 

 this specimen by a carnivore, at which point only the dorsal portion 

 of the tooth would be exposed to stomach acids (Gary Morgan, Florida 

 Museum of Natural History, personal communications). Separation of 

 the molar from the dentary bone may have occurred during or after 

 fossilization. This species is a good indicator of nearby bodies of 

 permanent water; its diet consists mostly of aquatic vegetation. It 

 builds its nest in areas such as open savannahs, mangroves, and in 

 suitable stumps (Kurten and Anderson 1980). 



This is the first fossil record of the round-tailed muskrat outside 

 of Florida and Georgia. 



Synaptomys cooperi - Southern Bog Lemming 

 Material: 1 right Ml (.155). 



Remarks: The molar from the Ardis site compares favorably to recent 

 specimens of this species. Separation of Synaptomys cooperi from 

 S. australis is based on size, as S. cooperi is generally 35% smaller 

 than S. australis (Simpson 1928, Olsen 1958). The occlusal length 

 (2.2 mm) of the Ardis Ml referred to S. cooperi is comparable to the 

 lowest range given by Guilday et al. (1977). 



The southern bog lemming can be found in habitats that include 

 grasslands, moist meadows, woodlands, thickets, weedy fields, and 

 bogs (Webster et al. 1985). 



Synaptomys cooperi does not occur in the State today; the nearest 

 populations are found in the Piedmont and mountains of Virginia and 

 North Carolina, respectively, extending north into Maryland, and westward 

 into Kansas and Nebraska (Hall 1981). S. cooperi also occurs in the 

 Great Dismal swamp and on the Coastal Plain of North Carolina 

 (Clark et al. 1993). 



This is the first fossil record of the southern bog lemming from 

 South Carolina. 



