A new horned lizard from Guerrero, Mexico

Phrynosoma sherbrookei. Photographer unknown
The journal Herpetological reports a new species of horned lizard in the genus Phrynosoma from southwest México. Body size, tail length, and scale texture and layout distinguish the new species, Phrynosoma sherbrookei. The new species is named after Wade Sherbrook, who has studied horned lizard behavior, ecology and systematics for many years.

There are 16 recognized horned lizard species, ranging from Canada to Guatemala. Only four species have been found south of México's trans-volcanic belt. These distinctive reptiles have a dorsum covered with spiny scales and bony horns on their heads. To avoid predators, they rely on camouflage and an ability to puff out their body. Some species squirt blood by rupturing capillaries surrounding their eyes when attacked by a canid predator. The blood contains formic acid, sequestered by the lizards from the ants they feed on. They are adapt to dry habitats, collecting rainwater by using their dorsal surface to channel water over their back and into their mouth. Some species are live bearing while other populations of the same species lay eggs.

In Guerrero, México, 14 lizards from the Sierra Madre del Sur were found to be an unrecognized species. Adrián Nieto-Montes de Oca and colleagues analyzed DNA from these specimens to support their proposal of a new species. They also generated a phylogenetic tree depicting the evolution of the horned lizards.

The new species can be distinguished from all other Phrynosoma by the possession of a unique combination of morphological characteristics. The molecular genetic data include three fragments of the mitochondrial genome and six nuclear genes (2419 and 3909 base pairs in total, respectively) for 31 samples belonging to the 16 previously recognized species of Phrynosoma and the new species

Phrynosoma sherbrookei is strongly supported in maximum likelihood analyses of both the concatenated mitochondrial and nuclear data as a monophyletic, distinct evolutionary lineage sister to, and moderately divergent from, P. taurus, and highly divergent from all of the other species of Phrynosoma. A Bayesian species tree analysis also strongly supports the monophyly of the Brevicauda clade, and a sister relationship between P. taurus and the new species.

Phrynosoma sherbrookei seems to live in a small area and may benefit from protection until researchers can learn more about the population.


Citation
Adrián Nieto-Montes de Oca, Diego Arenas-Moreno, Elizabeth Beltrán-Sánchez, and Adam D. Leaché (2014) A New Species of Horned Lizard (Genus Phrynosoma) from Guerrero, México, with an updated multilocus phylogeny. Herpetologica 70: 241-257.