Body temperatures of two viviparous Liolaemus lizard species, in Patagonian rain forest and steppe

IBARGUENGOYTIA, N. R. Y CUSSAC, V. E.

HERPETOLOGICAL JOURNAL

BRITISH HERPETOL SOC

Año: 2002 p. 131 - 134

0268-0130

The genus Liolaemus, with at least 160 known species, is broadly distributed from the highlands of Peru and Bolivia to Tierra del Fuego, and from the Pacific islands of Chile to coastal Brazil (Cei, 1986). Liolaemus elongatus and Liolaemus pictus are distributed along an east-west precipitation gradient from the Patagonian steppe to the rainforest and they are sympatric in the transition zone located along the east of the Andes. Liolaemus elongatus is a saxicolous, viviparous, medium- to large-sized lizard (23 - 90 mm snout-vent length, adults and juveniles included). This species is distributed from San Juan to Chubut and is associated with steppe environments (Cei, 1986), but it has been found in the rainforest-steppe transition, in a very humid, cloudy microhabitat, syntopic with Liolaemus pictus (Ibargüengoytía & Cussac, 1998). Liolaemus pictus is a viviparous, medium-sized lizard (23-75 mm snout-vent length, adults and juveniles included) that lives in temperate habitats from sea level to moderate elevations (1600 m), in leaf-litter and under logs (Donoso-Barros, 1966). We have shown previously that L. elongatus has an annual or biennial female reproductive cycle, while L. pictus has a biennial or triennial female reproductive cycle. As there is a strong association between the rate of embryonic development and temperature (Heulin, Osenegg & Lebouvier, 1991; Gilbert, 1994; Andrews, Mathies, Qualls & Qualls, 1999), we suggested that the low frequency of reproduction observed in these species is related to a short, cold, active season which constrains opportunities for thermoregulation, in turn affecting vitellogenesis and embryonic development (Ibargüengoytía & Cussac, 1996; 1998). In the present work, we report the body temperatures of Liolaemus pictus and L. elongatus two sintopic species in part of their distribution.