Kinosternon baurii

Adults have a broad, smooth, oval, tan to black carapace (generally widest and highest behind the middle) with three yellowish or cream-colored longitudinal stripes (may be obscure or lacking in some localities) and a large olive to yellow plastron that has two transverse hinges and may have dark seam borders; plastral hinges, absent in hatchlings, are acquired in about three months (Einem 1956); vertebrals may be depressed, forming a shallow, middorsal groove (Carr 1952, Ernst and Barbour 1972); head is small and conical and generally has two light cream to yellow stripes on each side; fleshy barbels occur on the chin and neck; upper jaw is not hooked; tail is spine-tipped; carapace has 23 scutes around the margin, including the cervical (nuchal); in southern Florida, young are black with a yellow spot on each marginal scute (Ashton and Ashton 1985), and they have a rough carapace with a narrow middorsal keel and weak dorsolateral keels (absent in adults); adult males differ from adult females in having a longer thicker tail (vent posterior to rear edge of carapace) and a patch of rough scales on the inner surface of the hind leg; carapace length usually 7.5-10 cm in adults, maximum 116 mm over much of range (Einem 1956, Iverson 1979, Wygoda 1979) but reaches 125-127 mm in southern Florida (Meshaka 1988). See Ernst and Barbour (1989) and Conant and Collins (1991).

Differs from musk turtles (genus STERNOTHERUS) in having a noticeably larger plastron and two plastral hinges (vs. one). Specimens from the northern part of the range often have been misidentified as K. SUBRUBRUM. Lamb and Lovich (1990; see also Copeia 1991:561) found that the following characteristics reliably distinguished K. BAURII from K. SUBRUBRUM SUBRUBRUM. BAURII: carapace stripes present, greatly reduced, or absent; side of head bearing a pair of stripes, either continuous or broken; canthal stripe typically extends anteriorly from eye to tip of snout; in males, ratio of posterior humeral/plastron length (PH/PL) falls between 0.29-0.33 and ratio of plastral forelobe length/plastron length (FL/PL) falls between 0.35-0.38; in females, PH/PL falls between 0.28-0.35 and FL/PL falls between 0.32-0.35. SUBRUBRUM: carapace stripes absent; side of head variable, from no markings to extensive spotting or stripelike patterning, but seldom involving a pair of stripes; if side of head is patterned, then canthal stripe, if present, does not extend anterior of eye; in males, PH/PL falls between 0.25-0.28 and FL/PL falls between 0.39-0.42; in females, PH/PL falls between 0.24-0.28 and FL/PL falls between 0.36-0.39. See Lamb and Lovich (1990) for further information on distinguishing BAURII from SUBRUBRUM in Georgia, the Carolinas, and Virginia. See Lovich and Lamb (1995) for information on distinguishing K. SUBRUBRUM HIPPOCREPIS from K. BAURII.

Cypress swamps, sloughs, ponds, drainage canals, wet meadows, shallow marshes, and adjacent forest areas; wanders on dry land and enters brackish ponds (e.g., in the Florida Keys; Dunson 1981). Often observed on roads and along canal banks (Carr 1940, Duellman and Schwartz 1958). Sometimes digs into decaying vegetation or soil surface. In central Florida, sometimes estivates on land when water levels are low; returns to water after rains raise water levels (Wygoda 1979). May less aquatic in the north than in southern Florida, where habitats more often include deeper flowing waters and where estivation on land is rare or absent (Ernst et al. 1972, Iverson 1979). However, in the lower Florida Keys, habitats include shallow ponds and excavated mosquito control ditches, and turtles may use terrestrial retreats if the ponds dry or become too saline (Dunson 1992).

Eggs are laid in nests dug in sand or decaying vegetation (Ernst and Barbour 1972, Iverson 1979). Sometimes oviposits in alligator nests. Nesting areas in Florida include turkey oak-longleaf pine sandhills adjacent to swamps; may travel up to at least 50-100 meters to nest (Mushinsky and Wilson 1992). After ovipositing, females often burrow underground a few meters from the nest, and then move back to wetland habitat after the next rain (Wilson, unpubl.).

In central Florida, many adults have missing limbs and eyes and damage to the shell that could be attributed to predation attempts (Wilson, unpublished).

Leeches commonly are attached to the limbs or shell. The shell sometimes has attached algae (Neill and allen 1954).

In a single year in central Florida, 90% of 252 nesting events occurred during September-January, 2% in February-April, and 8% in May-June; most nesting occurred after heavy rainfall (Wilson, unpubl.; see also Wilson 1998). Clutch size is 1-7, usually 2-3. Average clutch size increases with female size. Mature females lay up to 3-6 clutches/year (Iverson 1979), 1-3/year in central Florida (Wilson, unpubl.). Eggs hatch in 97-143 days in the laboratory (Einem 1956, Lardie 1975, Iverson 1979). Iverson (1977) reported incubation times of 113-128 days. Because embryos exhibit diapause and estivation (Ewert 1985, 1991) at cool temperatures, incubation times in the field may be considerably longer than those in the laboratory. Sex of the hatchlings is affected by incubation temperature (Etchberger 1991). Eggs may incur heavy predation (Wilson, unpubl.). Hatchlings may overwinter in nest and emerge to move to wetlands in early to late spring (mainly winter-spring in Florida), usually following a heavy rain; a few hatchlings can be found traveling on land in fall (Mushinsky and Wilson 1992; Wilson, unpubl.). Females mature at an age of 5-6 years, when plastron length is 70-75 mm (Iverson 1979). Mature males have been reported with a plastron length of 76 mm or more (Einem 1956), though males may mature earlier and at smaller sizes than do females (Carr 1952). Maximum longevity in captivity is at least 25 years (Ernst and Barbour 1972).