1 4 Curtis C. Bentley and James L. Knight 



ley and Knight (1993), and the following associated cranial and postcranial ele- 

 ments; articulated skull fragment (prefrontal, frontal, postorbital, parietal, and 

 supraoccipital), right maxilla, both quadrates, both opisthotics, basisphenoid, and 

 articulated lower jaw, 1st cervical vertebra, 2 humeri, 1 ulna, 2 coracoids, 1 ischi- 

 um, partial pubis and ilium, 1 sacral rib, 1 fibula, 3 phalanges, and vertebrae 

 fragments. An individual specimen consisting of a partial carapace and plastron 

 missing only the left hypoplastron and xiphiplastron (.299). Isolated skull frag- 

 ment (parietal, supraoccipital, both maxillae, basisphenoid, 1 quadrate, 1 postor- 

 bital, 1 partial squamosal) (.299.1). A single sub-adult individual with partial 

 plastron and 2 peripherals (.12 1.1 -.12 1.2). 



Isolated elements: 17 nuchals (SCSM 93.90.2-.8)(5 USNM)(5 UF); 3 

 right and 2 left 2nd costals (.334-.338); 6 right and 5 left 3rd costals (.339-349); 



6 left and 6 right 4th costals (.350-.361); 3 right and 2 left 5th costals (.362-366); 



7 right and 4 left 6th costals (367-377); 1 left 7th costal (378); 34 peripherals 

 (300-333); 5 right and 3 left epiplastra (379-386); 3 entoplastra (.417-.419); 5 

 right and 13 left hyoplastra (387-399,.432)(2 USNM)(2 UF); 3 left hypoplasia 

 (.400-.402); 6 right and 10 left xiphiplastra (.403-.416)(l USNM)(1 UF); 1 

 mandible (.757); 3 humeri (.426-.428); 6 femora (.420-.425). 



Characters used for identification: Identification of the two most complete spec- 

 imens is discussed by Bentley and Knight (1993). 



Nuchals - See Bentley and Knight (1993), for characters used to distin- 

 guish this from other possible identifications. 



Epiplastron - Differs from C. picta in that the scute overlap area is more 

 robust in C. guttata, and the anterior edge is not serrated as is common with C. 

 picta. It can be separated from C. muhlenbergii because the bulbous area where 

 the gular sulcus wraps onto the scute overlap is usually considerably wider medi- 

 ally to laterally in specimens of C. guttata, whereas the scute overlap portion that 

 is posterior to the bulbous area is narrower in C. muhlenbergii than C. guttata. 

 The length of the scute overlap posterior to the gular sulcus is longer than that of 

 C. picta. Also, the epidermal attachment scar in C. muhlenbergii is deeply 

 incised and tends to undercut the scute overlap area. The epiplastron of C. gut- 

 tata is rarely incised to this extent. The epiplastra of C. insculpta differ from C. 

 guttata in that the bulbous area where the gular sulcus crosses the dorsal surface 

 is only slightly or not at all bulbous in specimens of similar size. The epiplas- 

 tron of Deirochelys, Trachemys and Pseudemys that fall within the size range of 

 C. guttata have less pronounced scute overlap area compared to that of C. gutta- 

 ta. E. blandingii specimens of comparable size show sub-adult traits (incomplete 

 ossification) and have a less pronounced scute overlap area. Terrapene epiplas- 

 tra differ in that the area posterior to the scute overlap is concave, forming a 

 depression posteromedially to the gular sulcus, generally absent in C. guttata. 



