Kinosternon integrum (Le Conte 1854)

The Mexican Mud Turtle, Kinosternon integrum (family Kinosternidae), is a very wide-ranging freshwater turtle distributed from northwestern Mexico (Sonora) southward along the Pacific coast and across the Mexican Plateau nearly to the Isthmus of Tehuantepec. Kinosternon integrum is one of the largest species in the genus, with the larger males typically reaching 210 mm of maximum straight-line carapace length (SCL), and the smaller females reaching 190 mm SCL; there are extraordinary records for males of 220 and 223 mm SCL and 810 g in body mass. It is apparently parapatric with its close relatives K. cruentatum, K. mexicanum, K. chimalhuaca, and K. oaxacae, but occurs in broad sympatry with other related species (K. alamosae and K. hirtipes). Although it has extensive geographic variation, no subspecies are currently recognized. It is omnivorous and inhabits nearly every aquatic habitat within its range, but also regularly estivates terrestrially. Population densities are among the highest known for turtles. Females nest from at least May through October, producing multiple clutches of 3–11 eggs each. Eggs exhibit embryonic diapause and require chilling for development to commence; thus, hatching occurs during the rainy season the year following nesting. The species is incredibly abundant in many areas, despite the fact that it is sold in markets for human consumption and that human manipulation of water resources may threaten some populations.

Mexico. Occurs from northwestern Mexico (southern Sonora) and northeastern Mexico (southwestern Tamaulipas) to the Mexican Transvolcanic Belt, the upper Papalopapan basin in Puebla, and the Sierra Norte of Oaxaca. Along the coast of the Pacific, the distribution extends from southern Sonora through Sinaloa, Nayarit, and Jalisco, parapatric to the range of Kinosternon chimalhuaca in Jalisco and Colima, and continuing along the coasts of Colima, Michoacán, and Guerrero, where it abuts the distribution of K. oaxacae. Kinosternon integrum is the freshwater turtle with the largest distribution in Mexico.

Kinosternum integrum Le Conte 1854, Cinosternum integrum, Thyrosternum integrum, Thyrosternon integrum, Cinosternon integrum, Kinosternon integrum, Swanka integra, Cinosternon integrum, Cinosternum scorpioides integrum, Cinosternon rostellum Bocourt 1876, Cinosternon guanajuatense Dugès 1888 (nomen nudum), Cinosternum scorpioides integrum mexicana Siebenrock 1907 (unavailable name), Kinosternon iversoni Joseph-Ouni, Vander Schouw, McCord, Frewer, and Uhrig 2025b, Kinosternon mariamadre Joseph-Ouni, Vander Schouw, Frewer, Uhrig, and McCord 2025c.

No subspecies are currently recognized.