Stejneger, 1925b
Herrera's mud turtle
Recognition
This species has a relatively long (to 17.2 cm), slightly domed carapace which is wider behind the middle. The 1st vertebral scute is elongated and extremely narrow; it never touches the 2nd marginals. Vertebrals 2-5 are broader than long or at least as broad as long. Adults have a single low medial keel; juveniles may have two lateral keels as well. Marginals 10 and 11 are elevated above those preceding. Only four neurals are present, separating only costals 2-5. The carapace is olive to brown with darkened seams. The plastron is narrow (smaller than the carapacial opening) and notched posteriorly. Its anterior lobe is longer than the posterior lobe in males, but the opposite in females. The posterior hinge is akinetic. The rigid abdominal scute is shorter than either anterior or posterior lobe, being about 20-30% of the maximum plastral length. The gular scute is usually less than half the length of the anterior lobe, and the interpectoral seam less than 10% of the maximum plastral length. The plastral formula is: an > abd > hum > gul > fem > pect. Bridge length is approximately 18-20% that of the plastron; there is axillary and inguinal contact. Both plastron and bridge are yellow to light brown, unmarked or with darker seams. The large head has a slightly projecting snout, a strongly hooked upper jaw, and its rostral scale is bifurcated posteriorly. Skin of the head is grayish brown and spotted dorsally and laterally; the cream-colored jaws are darkly streaked. Two chin barbels are present. The limbs are grayish brown and spotted with darker brown. The tail ends in a horny spine.
There are 56 chromosomes in the karyotype (Bickham and Carr, 1983).
Males are larger than females, and have long, thicker tails and a patch of raised horny scales on their thighs and crura. Females have relatively larger plastra (Carr and Mast, 1988).
Distribution
Kinosternon herrerai occurs in Gulf drainages in Tamaulipas, Veracruz, San Luis PotosÃ, Hidalgo, and Puebla, east-central Mexico.
Habitat
Kinosternon herrerai lives in free-flowing to seasonally intermittent waterways at elevations below 800 m. Carr and Mast (1988) found a balanomorph barnacle on the carapace of a male from the Arroyo La Coma stream (Tamaulipas, Mexico), indicating it must have inhabited brackish water.
Natural History
A description of courtship behavior has been provided by Carr and Mast (1988). All activity takes place on the bottom under water. A courting male mounts the female and grips her carapace with all four feet. Copulation quickly follows, with the terminal spine on the male's tail aiding intromission. The male then extends his head and neck forward and downward over the female's head, sways his head laterally back and forth, and rubs her anterior plastral rim with his gulars. She terminates copulation by crawling out from under, hopping, and rocking until he withdraws his penis. Copulation lasts at least five minutes.
Carr and Mast (1988) estimated a clutch consists of 2-4 brittle-shelled eggs (35.0 x 18.0 mm).
Kinosternon herrerai is omnivorous, feeding on wild figs, beetles, ants, millipedes and several other invertebrates (Carr and Mast, 1988); Poglayen's (1965) captive ate meats and fish. Kinosternon herrerai is active during day- as well as nighttime (Carr and Mast, 1988).
IUCN Red List Status (1996)
Not listed.