Kinosternon iversoni sp. nov. (Testudines: Kinosternidae), A New Species of Mud Turtle from Sonora and Sinaloa, Mexico

Following the neotype designation and sensu stricto redefinition of Kinosternon integrum Le Conte, 1854 by Joseph-Ouni et al. (2025), the populations of mud turtles in the northwestern Mexico coastal Pacific drainages formerly assigned to that taxon are currently examined here and found to constitute a distinct undescribed species in the K. integrum complex. The honorific patronym Kinosternon iversoni sp. nov. is dedicated to Dr. John B. Iverson for his lifelong work in spearheading and edifying Kinosternon research throughout the Americas. The new species is distinguished from K. integrum sensu stricto by a full suite of characters delimiting color, head and shell morphology and metrics and it appears to be endemic to the region from the lower Rio Yaqui and Rio Matape, Sonora south to the Rio Mocorito, Sinaloa, Mexico. This distribution partially corresponds to the drainage ranges 1A, 1B, and 2 expounded in Berry (1978). Sympatric freshwater turtle species are Kinosternon alamosae, Trachemys yaquia and Trachemys nebulosa hiltoni; it shares the same general type locality, Guírocoba, Sonora, with the latter taxon. We propose 85 of the 246 characters in the suite that differentiate male Kinosternon iversoni sp. nov. from K. integrum sensu stricto, and 77 characters for females.