Thursday, July 21, 2016

[Herpetology • 2016] Parallel Selective Pressures Drive Convergent Diversification of Phenotypes in Pythons and Boas


Figure 1: Convergent ecological guilds in pythons and boas. Examples of pythons and boas that display a similar micro-habitat or guild and look phenotypically similar. Species pairs from top to bottom and left to right along with the author of the photograph are as follows. 
Arboreal: 
Morelia viridis (John Rummel) and Corallus caninus (Pedro Bernardo). Semi-arboreal: Simalia kinghorni (Kieran Palmer) and Chilabothrus angulifer (Milan Kořínek).  Terrestrial: Antaresia childreni (Dan Lynch) and Epicrates maurus (Esteban Alzate).  Semiaquatic: Liasis mackloti (George Cruiser) and Eunectes murinus (Marcio Lisa/Txai Studios). Semi-fossorial: Aspidites ramsayi (Steve Wilson) and Lichanura trivirgatta (Pedro Bernardo). 

Abstract

Pythons and boas are globally distributed and distantly related radiations with remarkable phenotypic and ecological diversity. We tested whether pythons, boas and their relatives have evolved convergent phenotypes when they display similar ecology. We collected geometric morphometric data on head shape for 1073 specimens representing over 80% of species. We show that these two groups display strong and widespread convergence when they occupy equivalent ecological niches and that the history of phenotypic evolution strongly matches the history of ecological diversification, suggesting that both processes are strongly coupled. These results are consistent with replicated adaptive radiation in both groups. We argue that strong selective pressures related to habitat-use have driven this convergence. Pythons and boas provide a new model system for the study of macro-evolutionary patterns of morphological and ecological evolution and they do so at a deeper level of divergence and global scale than any well-established adaptive radiation model systems.

Keywords: Adaptive radiation, ecomorphology, henophidia, snakes.

Figure 1: Convergent ecological guilds in pythons and boas. Examples of pythons and boas that display a similar micro-habitat or guild and look phenotypically similar. Species pairs from top to bottom and left to right along with the author of the photograph are as follows.
 Arboreal: Morelia viridis (John Rummel) and Corallus caninus (Pedro Bernardo). Semi-arboreal: Simalia kinghorni (Kieran Palmer) and Chilabothrus angulifer (Milan Kořínek).  Terrestrial: Antaresia childreni (Dan Lynch) and Epicrates maurus (Esteban Alzate).  Semiaquatic: Liasis mackloti (George Cruiser) and Eunectes murinus (Marcio Lisa/Txai Studios). Semi-fossorial: Aspidites ramsayi (Steve Wilson) and Lichanura trivirgatta (Pedro Bernardo).

Damien Esquerré and J. Scott Keogh. 2016. Parallel Selective Pressures Drive Convergent Diversification of Phenotypes in Pythons and Boas. Ecology Letters. 19: 800–809. DOI: 10.1111/ele.12620 



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