Kinosternon sonoriense (LeConte 1854) – Sonora Mud Turtle, Desert Mud Turtle, Sonoyta Mud Turtle, Casquito de Sonora

Abstract

The Sonora Mud Turtle, Kinosternon sonoriense (Family Kinosternidae), is a medium-sized kinosternid (females to 175 mm SCL, males to 168 mm SCL) found in lentic and lotic aquatic habitats in desert and montane regions of the southwestern United States and northwestern Mexico. Two allopatric subspecies are currently recognized, K. s. sonoriense and K. s. longifemorale. Although primarily aquatic, individuals frequently move along aquatic corridors, make extensive overland movements, and estivate on land. Kinosternon sonoriense is omnivorous, matures in 5-9 yrs, and exhibits considerable geographic variation in growth and maturation. Average clutch size is usually related to female body size and ranges from 3 to 11 eggs. Eggs average 28-33 mm in length, 14-19 mm in width, and weigh 5-6 g. Females produce one to two clutches per year (potential maximum of four), and embryos exhibit temperature-dependent sex determination. The loss and degradation of natural aquatic habitats, including streams, spring runs, and ciénegas, is a primary threat to conservation of K. sonoriense, particularly to the very small, isolated populations of K. s. longifemorale. The loss of natural habitats has been partially mitigated by the widespread construction of impoundments; however, many impoundments are now experiencing dam failure and siltation, further contributing to habitat loss. In addition, the establishment of non-native predator species, particularly Virile Crayfish and American Bullfrogs, are known threats to juvenile K. s. sonoriense. The status and ecology of both subspecies have been studied in recent years, mainly in the United States, and conservation efforts have been focused primarily on the declining populations of K. s. longifemorale. distribution. -Mexico, USA. Kinosternon sonoriense occurs from southwestern New Mexico and western Chihuahua west through much of Arizona and Sonora. Historically known populations in the lower Colorado River basin of southwestern Arizona, southeastern California, and possibly northern Baja California and southern Nevada have apparently been extirpated.