Taxonomy :

Two subspecies are recognized within P. thalassinus; P. t. thalassinus inhabits the Cape region, and P. t. repens ranges north of the isthmus of La Paz. P. t. repens differs by having a thin, black, postorbital stripe; one row of scales between the nasal and the supralabials as opposed to two, and reaching a maximum snout-to-vent length of 111 mm as opposed to 162 mm. Genetic studies indicate all populations within P. thalassinus, including the two subspecies, show only low levels of genetic divergence, indicative of high rates of gene flow. In contrast, P. thalassinus is strongly differentiated from its sister species P. mearnsi.

Life History :

Breeding takes place in the spring. 20 to 30 eggs are laid in late spring and summer, and hatchlings appear after 85 to 88 days in summer and early fall. Sexual maturity is reached after about 2 years with a life expectancy of 20 years.

Habitat :

P. thalassinus is most often found in the immediate vicinity of rocky canyons, boulder-strewn hillsides and arroyo bottoms and sea-side cliffs. These lizards appear to be particularly common on rocks near large trees or other vegetation, and rarely seen in areas where vegetation is non-existent.

Geographic range :

It is found in the Sierra la Laguna (and its associated ranges) and Sierra la Trinidad of the Cape region of Baja California Sur, as well as on Islas Espiritu Santo and Partida Sur in the Gulf. Elevational distribution from sea level to 2,020 meters in the Sierra la Laguna.