8 Curtis C. Bentley and James L. Knight 



Material: 3 nuchals (.22-.24); 2 right hyoplastra (.14-. 15); 1 right, 5 left 

 hypoplasia (.16-. 21). 



Characters used for identification: Identification is based on characters provid- 

 ed in discussion for Kinosternon subrubrum. The hyo-hypoplastron of S. minor 

 can be separated from the same elements in S. odoratus because the area that 

 forms the bridge between the plastron and the carapace is dorsally compressed 

 or flattened in S. minor, and not raised as in S. odoratus. The nuchals compare 

 most favorably to S. odoratus, following the characters used above, and addi- 

 tionally exhibit a strong dorsal medial keel that is generally lacking in K. sub- 

 rubrum. 



Remarks: The common musk turtle inhabits areas very similar to that of K. sub- 

 rubrum, preferring slow to non-moving bodies of water with a soft bottom. It 

 has also been collected from fast moving, gravel bottomed, streams (Ernst and 

 Barbour 1989). S. odoratus occurs from southern Maine and Canada southward 

 through Florida and as far west as Kansas and central Texas (Conant and Collins 

 1991), and occurs in the area of the Ardis site today. 



Chelydridae 

 Chelydra serpentina - Snapping turtle (Linnaeus, 1758) 



Material: 2 right parietals (.50, .53); 1 left postorbital (.51); 1 right prefrontal 

 (.52); 1 left quadratojugal (.54); 1 partial left mandible (.55); 2 right mandibles 

 C56-.57); 6 cervical vertebrae (.102-. 107); 1 humerus (.63); 2 radii (.69-.70); 1 

 right scapulo-acromial process (.64); 1 right partial acromial process (.65); 5 

 femora (.58-.62); 3 ilia (.66-.68); 1 caudal vertebra (.108); 1 nuchal (.95); 1 right 

 1st peripheral (.71); 16 unassigned peripherals (.72-.83)(2 USNM)(2 UF); 1 left 

 1st costal (.84); 24 partial costals (.85-.92)(8 USNM)(8 UF); 2 associated costals 

 C93-.94); 2 neurals (.96-.97); 2 epiplastra (.100-. 101); 2 hypoplasia (.98-.99). 



Characters used for identification: Chelydra shell material is very distinctive and 

 easily separated from other turtles including Macroclemys. Preston (1979) pro- 

 vides characters that allow the identification of fragmentary material. All listed 

 fossil elements compare favorably to Recent skeletal materials. 



Axial and appendicular skeleton - The large size and diagnostic orna- 

 mentation of the Chelydra skull roof elements distinguish them from all other 

 turtles. Macroclemys lacks the rugose cranial ornamentation of Chelydra. A 

 pectoral girdle was assigned to this species based on the 90° angle between the 

 scapula and acromial process and on the heavily striated distal ends (Holman 

 1966). Femora and humeri could not be separated from Recent material of C. 

 serpentina, and are more robust than other genera of fresh water turtles (Holman 

 1964) except Macroclemys, which is generally considerably larger. 



