We describe a new species of mud turtle of the genus Kinosternon from the Pacific Coastal Plain of the Mexican states Sinaloa and Nayarit. The new species shares morphological characters with the recently described Kinosternon vogti, which are unique to these two turtles and separate them from the other species of the genus. The new species differs from K vogti by skin coloration, size, and the scutellation of both carapace and plastron. We also present a molecular phylogeny of the family Kinosternidae based on two mitochondrial and four nuclear loci. Our results show that the new species is most closely related to K. vogti, and together they form the sister group to the K. hirtipes and K integrum species groups of Kinosternon.

The genus Kinosternon in Mexico is represented by 12 species of which only 2 inhabit the lowlands of the central Pacific region (Kinosternon chimalhuaca and Kinosternon integrum). Based on 15 standard morphological attributes and coloration patterns of 9 individuals, we describe a new microendemic mud turtle species from the central Pacific versant of Mexico. The suite of morphological traits exhibited by Kinosternon sp. nov. clearly differentiates it from other species within the genus Kinosternon by a combination of proportions of plastron and carapace scutes, body size, and a large yellow rostral shield in males. The new species inhabits small streams and ponds in and near the city of Puerto Vallarta, Jalisco. Unfortunately, natural populations are unknown so far. The habitat is damaged by urban growth, and only one female is known. The available information would suggest that Kinosternon vogti sp. nov., is one of the most threatened freshwater turtle species. An urgent conservation program is... Resumen El género Kinosternon en México está representado por 12 especies, de las cuales solo dos habitan las tierras bajas de la región Pacífico central (Kinosternon chimalhuaca y K. integrum). Con base en la evaluación de quince atributos morfológicos y la coloración de nueve individuos, describimos una nueva especie de tortuga lodo micro-endémica del Pacífico central de México. El conjunto de rasgos morfológicos exhibidos por Kinosternon sp. nov., lo diferencia claramente de otras especies dentro del género Kinosternon por una combinación de proporciones de escudos de plastrón y caparazón, tamaño del cuerpo y un escudo rostral de color amarillo en los machos. La nueva especie habita pequeños arroyos y estanques en y cerca de la ciudad de Puerto Vallarta, Jalisco. No se conocen poblaciones naturales hasta el momento. El hábitat está dañado por el crecimiento urbano, y solo se conoce una hembra. La información disponible sugeriría que Kinosternon vogti sp. nov., es una de las especies de tortugas de agua...