Como as cobras perderam suas pernas

sábado, novembro 28, 2015

The burrowing origin of modern snakes

Hongyu Yi1,2,* and Mark A. Norell2

+ Author Affiliations

↵*Corresponding author. E-mail: v1hyi@staffmail.ed.ac.uk

Science Advances 27 Nov 2015:

Vol. 1, no. 10, e1500743

DOI: 10.1126/sciadv.1500743

Abstract

Modern snakes probably originated as habitat specialists, but it controversial unclear whether they were ancestrally terrestrial burrowers or marine swimmers. We used x-ray virtual models of the inner ear to predict the habit of Dinilysia patagonica, a stem snake closely related to the origin of modern snakes. Previous work has shown that modern snakes perceive substrate vibrations via their inner ear. Our data show that D. patagonica and modern burrowing squamates share a unique spherical vestibule in the inner ear, as compared with swimmers and habitat generalists. We built predictive models for snake habit based on their vestibular shape, which estimated D. patagonica and the hypothetical ancestor of crown snakes as burrowers with high probabilities. This study provides an extensive comparative data set to test fossoriality quantitatively in stem snakes, and it shows that burrowing was predominant in the lineages leading to modern crown snakes.

Keywordscrown snake origin HRCTinner earbony labyrinth virtual model building geometric morphometrics functional morphology ancestral state reconstructions

Copyright © 2015, The Authors

This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.

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