Multiple paths to aquatic specialisation in four species of Central American Anolis lizards

Abstract

Aquatic anoles present an interesting ecomorphological puzzle. On the one hand, the link between habitat use and morphology is well established as convergent within the Caribbean anole radiation. On the other hand, aquatic anoles do not appear to form an ecomorphological group – rather, it appears that there may be several ways to adapt to aquatic habitats. We explore this issue by examining the ecology, morphology and performance of four species of Central American aquatic anoles belonging to two different lineages. Overall, we find that aquatic anoles overlap in multiple ecological and morphological dimensions. However, we do find some differences in substrate use, claw and limb morphology, and bite force that distinguish Anolis aquaticus from the other three species (A. lionotus, A. oxylophus and A. poecilopus). Our results suggest that A. aquaticus is adapted to climb on boulders, whereas the other species utilise vegetation in streamside habitats.

Keywords:

• adaptation
• ecomorph
• functional morphology
• aquatic lizard
• Anolis

Acknowledgements

We thank the staff at La Selva, Friends of the Osa and Palo Verde Biological Station for their help finding these species and for their hospitality during our stay; the Costa Rican and Panamanian governments for expediting our research permits and allowing us to conduct this study; Rosario Castañeda for helpful information and feedback; three reviewers for their helpful suggestions on this manuscript, and José Rosado of the Museum of Comparative Zoology and Steven Poe of the Museum of Southwestern Biology at the University of New Mexico, for allowing us to access preserved specimens. A Miyata Award through the Museum of Comparative Zoology funded this study.