Is the number and size of scales in Liolaemus lizards driven by climate?

TULLI M J; CRUZ, F. B.

Integrative Zoology

Blackwell publishing inc.

Año: 2018

1749-4877

Ectothermic vertebrates are sensitive to thermal fluctuations in the environments where they3 occur. To buffer these fluctuations, ectotherms use different strategies, including the integument,4 which is a barrier that minimizes temperature exchange between the inner body and the5 surrounding air. In lizards, this barrier is constituted by keratinized scales of variable size, shape6 and texture, and its main function is protection, water loss avoidance and thermoregulation. The7 size of scales in lizards has been proposed to vary in relation to climatic gradients; however, it8 has also been observed that in some groups of Iguanian lizards could be related to phylogeny.9 Thus, here, we studied the area and number of scales (dorsal and ventral) of 61 species of10 Liolaemus lizards distributed in a broad latitudinal and altitudinal gradient to determine the11 nature of the variation of the scales with climate, and found that the number and size of scales are12 related to climatic variables, such as temperature and geographical variables as altitude. The13 evolutionary process that better explained how these morphological variables evolved was the14 Ornstein-Uhlenbeck model. The number of scales seemed to be related to common ancestry,15 whereas dorsal and ventral scale areas seemed to vary as a consequence of ecological traits. In16 fact, the ventral area is less exposed to climate conditions such as ultraviolet radiation or wind17 and is thus under less pressure to change in response to alterations in external conditions. It is18 possible that scale ornamentation such as keels and granulosity may bring some more19 information in this regard.