Narrow-bridged mud turtle
The low, oval, uniformly brown carapace (to 12 cm) is depressed and unkeeled in adults, but may be weakly tricarinate in juveniles. The posterior margin of the carapace is slightly notched, and the scutes overlap slightly in older individuals. Vertebrals 1-3 are about as broad as long; the 4th and 5th are much broader than long. The 1st or 3rd vertebral is longest and broadest; the 5th is the shortest and narrowest. The 1st vertebral touches the 2nd marginals; only the 10th marginal is elevated. The plastron is narrow, double hinged, and notched posteriorly. Its anterior and posterior lobes are, respectively, less than 39% and 34% of the maximum carapace length. In older individuals the plastral seams contain much soft pale tissue. The plastral formula is: abd > an > hum > fem > gul > pect. Width of the very narrow bridge is less than 21% of the maximum carapace length. The axillary and inguinal scutes are in contact on the bridge. Plastron and bridge are yellow, sometimes with dark seams. The head is only slightly broadened, the upper jaw is neither hooked nor notched, and the blunt snout does not protrude. Usually three to six cream-colored barbels are present in a longitudinal row on each side of the throat. Dorsally, the head is dark brown, changing gradually to tan and then cream on the sides of the snout. Lateral and ventral skin is pale cream. The iris is brown with gold flecks and the jaws are unmarked or only lightly marked with a few pale streaks. The limbs are gray to gray brown. Vinculae are present on the thighs and crura of males, and the tail of both sexes lacks a terminal horny spine.
Males are slightly shorter (to 11.5 cm) than females (to 12 cm) and have a bosslike enlargement of the snout in the prefrontal region and a long, thick prehensile tail. The female tail is short.
Kinosternon angustipons occurs on the Caribbean lowlands from the Rio San Juan on the Nicaraguan-Costa Rican border southward to Bocas del Toro Province, Panama.
This is a relatively rare denizen of shallow swamps with slow currents, soft bottoms, and warm temperatures.
Legler (1966) hypothesized (based on dissected females) that as many as four eggs may be laid, possibly singly, so several clutches may be laid each year. The only known egg was white, elliptical (40 x 22 mm), and had a brittle, semiglazed and irregularly lumpy (but not granular) shell.
Stomachs examined by Legler (1966) contained plant remains and an orthopteran insect. Adults were attracted to traps baited with canned sardines and bananas, and captives ate ground beef.
This species seems most closely related to Kinosternon dunni.
IUCN Red List Status (1996)