Turtles 2 7 



Mexico (Conant and Collins 1991). Only A. spinifera inhabits the area of the 

 Ardis site today. Dobie and Jackson (1979) reported "Trionyx sp." from Edisto 

 Island, South Carolina. Meylan (1987) has shown the correct name for North 

 American softshells to be Apalone. 



DISCUSSION AND PALEOECOLOGY 



The turtle assemblage of the Ardis local fauna provides important new 

 data for the late Pleistocene of the southeastern United States. In particular, it 

 documents a shift in the spatial patterns of several turtle species during the late 

 Pleistocene. The turtle fauna is unique in its geographical and temporal setting, 

 and it contains the first sympatric fossil occurrences of several taxa, e.g., Clem- 

 mys muhlenbergii, C. guttata, Emydoidea blandingii, Macroclemys temminckii. 



All of the fossil turtles collected from the site, except Hesperotestudo 

 crassiscutata and Terrapene Carolina major, are primarily aquatic and are com- 

 monly found in, or require, still or slow moving water with a soft substrate and 

 aquatic vegetation (Ernst and Barbour 1989). Additional evidence of a nearby 

 body of water included the presence of Alligator mississippiensis and elements 

 of the fish fauna which are currently under study. This agrees with the habitat 

 suggested by Bentley et al. (1994) based on the Ardis mammal fauna that indi- 

 cates an ecotone between a mixed forest of conifers, hardwoods and meadows, 

 and a permanent body of water such as a river or stream which may have given 

 way to a bog or marsh. Portions of the mammalian fauna and avian material 

 from the Ardis site further suggest the presence of a nearby large body of water 

 such as a lake or pond. This association is based on the life histories and habitat 

 requirements of many of the extant species represented in the Ardis fauna. 



The Ardis turtle fauna consists of thirteen extant and one extinct 

 species, with five taxa considered extralimital. Three of the five have northern 

 affinities: Emydoidea blandingii, Clemmys muhlenbergii, and Chrysemys picta. 

 Terrapene Carolina major has a strong southern affinity. Macroclemys has a pri- 

 marily Gulf coast distribution but extends as far north up the Mississippi Valley 

 as Iowa (Pritchard 1989). Although Hesperotestudo was widespread in North 

 America by the Miocene, Hibbard (1960) suggested that the presence of Hes- 

 perotestudo crassiscutata in a fauna indicated a mild climate with frost-free win- 

 ters. The sympatric occurrence of species that are apparently ecologically 

 incompatible today constitutes a "disharmonious fauna" (sensu Lundelius et al. 

 1983), which has been interpreted by many authors (Hibbard 1960, Holman 

 1980, Lindelius et al. 1983) as indicating a more equable climate (reduced sea- 

 sonal temperature gradients) than that experienced in the region today. The 

 Ardis local fauna reflects such a disharmonious biota, which clearly has no mod- 

 ern analogue. The turtle fauna corroborates conclusions made on the basis of the 

 Ardis mammal fauna (Bentley et al. 1994), which also suggests that a more 



