Mammals of the Ardis Local Fauna 21 



only left Ml (.31); 9 right dentaries (.32-35), (3 USNM), (2 UF); 

 8 left dentaries (.36-. 38), (2 USNM), (3 UF); 1 left ml (.39); 1 left 

 m2 (.40); 1 right m2 (.41); 1 right m3 (.49); 1 left m3 (.50); 4 right 

 Ml (.47, .48), (2 USNM); 4 left Ml (.42-. 45); 1 right M3 (.46), 1 left 

 M3 (.39); 1 left and 1 right lower incisor (.51, .52); 1 upper left 

 incisor (.53); 12 left femora (.54-. 59), (3 USNM), (3 UF); 10 right 

 femora (.60-. 63), (3 USNM), (3 UF); 9 left humeri (.64- .66), (3 

 USNM), (3 UF); 3 right humeri (.67- .69); 12 left tibio-fibula (.70- 

 .75), (3 USNM), (3 UF); 13 right tibio-fibula (.76- .82), (3 USNM), 

 (3 UF), 8 left ulna (.83-. 86), (2 USNM), (2 UF); 9 right ulna (.87- 

 .89), (3 USNM), (3 UF); 2 radii (.90- .91); 1 partial ilium (.92); 11 

 left partial innominates (.93- .97), (3 USNM), (3 UF); 11 right partial 

 innominates (.98-. 104), (2 USNM), (2 UF); 2 left 1st metatarsals (.105, 

 .106); 2 left 2nd metatarsals (.121, .122); 3 left 3rd metatarsals (.115- 

 .117); 3 right 1st metatarsals (.118- .120); 7 right 2nd metatarsals 

 (.107- .109), (2 USNM), (2 UF); 5 right 3rd metatarsals (.110- .112), 

 (1 USNM), (1 UF); 2 right 4th metatarsals (.113, .114); 3 calcanea 

 (.123- .125); 1 atlas vertebra (.126); 2 axis vertebra (.127, .128); 1 

 3rd cervical vertebra (.129); 2 5th cervical vertebrae (.130, 131); 3 

 6th cervical vertebrae (.132- .133), (1 USNM); 15 caudal vertebrae 

 (.135- .143), (3 USNM), (3 UF); 3 articulated caudal vertebrae (.134a- 

 c); 1 lumber vertebra (.144); 1 thoracic vertebra (.145); 9 vertebrae 

 (.146- .148), (3 USNM), (3 UF); 1 vertebra (.150); 1 sacral vertebra 

 (1 USNM); 1 sacral vertebra and two associated caudal vertebra (1 

 UF); 1 partial hyoid process (.149); 2 proximal rib halves (.151, .152). 



Remarks: The muskrat is by far the most common mammal from the 

 Ardis local fauna. The relatively high number of muskrat remains 

 from the site suggests that they may have been using the solution 

 cavities as temporary shelters. Given that the deposit at the Ardis 

 local fauna represents fluvial episodic events, these cavities may have 

 provided excellent temporary shelters if muskrats retreated from their 

 usual shelters onto higher ground during periodic flooding. This behavior 

 has been observed in muskrats using multiple shelters in areas with 

 seasonal fluctuations in water levels (Brooks 1985). In addition, pieces 

 of fossil turtle shell collected from the site had gnaw marks of a large 

 rodent, presumably muskrats, suggesting that feeding may have occurred 

 in these cavities. It is unlikely that the turtle shells were "wash-ins," 

 as no signs of weathering, water wear, or abrasive breakage were 

 evident. There have been many reports of contemporary muskrats 

 feeding upon turtles (Errington 1941, Doutt et al. 1966, Parmalee 

 1989), but no reports of this have been recorded from the fossil record. 



