An Anolis biporcatus enjoys some sun while balancing along a branch with the help of those neat adhesive toepads and claws.  Credit

An Anolis biporcatus enjoys some sun while balancing along a branch with the help of those neat adhesive toepads and claws.  Credit Wikimedia Commons.

In a recently published study, Cortés-Parra et al. (2021) compare the claws and toepads of mainland and island Anolis radiations in examination of “morphotype” diversity across phylogenetic and ecological scales. This study intersects nicely with quite recent work comparing the mainland and island radiations (e.g., Hiue et al. 2021; Patton et al. 2021), and claw morphology (e.g., Yuan et al. 2019, 2020; Falvey et al. 2020).

New literature alert!

Claws and toepads in mainland and island Anolis (Squamata: Dactyloidae): Different adaptive radiations with intersectional morphospatial zones

In Journal of Anatomy

Cortés-Parra, Calderón-Espinosa, and Jerez

Abstract:

Anolis lizards have evolved morphologies in response to different selective factors related to microhabitat use. Morphological diversity exhibits evolutionary patterns that reveal similarities and unique regional traits among the mainland and island environments and among Greater Antilles and Lesser Antilles islands. In the Greater Antilles and mainland environments anole species are classified into morphological/ecological groups, that are known as morphotypes (mainland) or ecomorphs (Greater Antilles). Morphotypes are defined only with morphological information; in contrast, for ecomorph assignment both morphology and ethology are required. For mainland species distributed in northwestern South America 10 morphotypes were proposed to include the morphological diversity of 59 species. We obtained data from body size, limbs length, tail length, and the number of lamellae for an additional ten species occurring in the same region and assigned them into morphotypes. We also collected data of the claw and toepad diversity of mainland and island Anolis from northwestern South America and compared it to the claw and toepads morphology recorded for the Greater Antilles and Lesser Antilles islands, under a phylogenetic framework. We found new island morphotypes (MT11–MT13) of Anolis from northwestern South America. When comparing claws and toepads morphology among the 13 morphotypes we found that morphological variation of these traits partially corresponds to morphotype groups. For instance, habitat specialist species like Anolis heterodermus, classified in morphotype 4 (MT4), have a characteristic design of broad toepad and reduced claws, and non-unique design of toepads and claws occurs in morphotypes MT1, MT2, MT5, MT10, and MT13. We also compared claws and toepads of fore and hindlimbs within the same individual, and found that even if limbs show differences in claws and toepads, suggesting that they perform differential biomechanical function, the degree of within individual variation is specific and not related to morphotype assignment. Our data supported the convergent and unique regional evolution among mainland and island anoles, and revealed aspects of correlative evolution of functional traits of claws and toepads that probably are related to minor differences in microhabitat use among mainland and island species, as suggested by previously published literature. Lastly, the evolutionary pattern of morphological diversity of claws and toepads of Anolis in the mainland and island environment supports both unique regional traits and common selective and historical factors that have molded Anolis morphological diversity.

Literature Cited:

Cortés‐Parra, C., Calderón‐Espinosa, M. L., & Jerez, A. (2021). Claws and toepads in mainland and island Anolis (Squamata: Dactyloidae): Different adaptive radiations with intersectional morphospatial zones. Journal of anatomy.

Falvey, C. H., Aviles-Rodriguez, K. J., Hagey, T. J., & Winchell, K. M. (2020). The finer points of urban adaptation: intraspecific variation in lizard claw morphology. Biological Journal of the Linnean Society, 131(2), 304-318.

Huie, J. M., Prates, I., Bell, R. C., & de Queiroz, K. (2021). Convergent patterns of adaptive radiation between island and mainland Anolis lizards. Biological Journal of the Linnean Society, 134(1), 85-110.

Patton, A. H., Harmon, L. J., del Rosario Castañeda, M., Frank, H. K., Donihue, C. M., Herrel, A., & Losos, J. B. (2021). When adaptive radiations collide: Different evolutionary trajectories between and within island and mainland lizard clades. Proceedings of the National Academy of Sciences118(42).

Yuan, M. L., Wake, M. H., & Wang, I. J. (2019). Phenotypic integration between claw and toepad traits promotes microhabitat specialization in the Anolis adaptive radiation. Evolution73(2), 231-244.

Yuan, M. L., Jung, C., Wake, M. H., & Wang, I. J. (2020). Habitat use, interspecific competition and phylogenetic history shape the evolution of claw and toepad morphology in Lesser Antillean anoles. Biological Journal of the Linnean Society129(3), 630-643.

Aryeh Miller