Zoological Studies

Vol. 54, 2015

Geometric morphometric analysis of the head of Microlophus atacamensis (Tropiduridae) in a latitudinal gradient

Soledad Ibáñez1*, Marcela A Vidal1, Juan Carlos Ortiz2 and Fernando Torres-Pérez3

1Departamento de Ciencias Básicas, Facultad de Ciencias, Universidad del Bío-Bío, Casilla 447, 4051381 Chillán, Chile
2Departamento de Zoología, Facultad de Ciencias naturales y Oceanográficas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
3Instituto de Biología, P. Universidad Católica de Valparaíso, Av. Universidad 330, Campus Curauma, Valparaíso, Chile

Background: Clinal variation is defined as gradual variation in a character associated with geographic distance among sites. Microlophus atacamensis is a medium large lizard species which inhabits the intertidal zone of northern Chile, distributed from Antofagasta (23° 39′ S) to Arrayán, La Serena (29° 41′ S) in a gradient which could show clinal variation. Geometric morphometrics analyzes differences in shape independent of size; information about shape allows a more complete biological interpretation than information on morphological variation. This study evaluated clinal variation in the head shape of M. atacamensis from five localities (Antofagasta, Paposo, Pan de Azúcar, Caldera, and Tres Playitas) using dorsal and lateral views, comparing form variation with latitudinal distribution. The heads of adults collected were photographed in lateral and dorsal views.
The analysis did not find significant differences in form among the five localities, in contrast to the proposal of earlier studies, and no differences were recorded between the sexes. Possible reasons why these populations are not differentiated in the latitudinal gradient are discussed.
Conclusions: Our results show that there are no differences between the studied, among the explanations are that populations of this species are subjected to similar environments that promote convergence of the structures analyzed.

Key words: Atacama Desert; Lizard; Shape morphometrics; Head.

*Correspondence: E-mail: soledadibanez7@gmail.com