The bizarre skull of Xenotyphlops sheds light on synapomorphies of Typhlopoidea

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The emerging picture of non-monophyly of scolecophidian snakes is increasingly indicative that fossorial lifestyle, myrmecophagous diet, and miniaturisation are powerful drivers of morphological evolution in squamate skulls. We provide a detailed description of the skull of Xenotyphlops grandidieri, with reference to the skulls of other scolecophidian snakes. The skull, which shows dramatic ventral inflection of the snout complex, is remarkably bizarre, and the mouth opening is more ventrally oriented than in other typhlopoids. The eyes are strongly reduced, and the enlarged and rather flat anterior head shield is covered in numerous sensillae. We put forward several potential explanations for the evolution of these unusual modifications. On the other hand, Xenotyphlops shares numerous synapomorphies with other typhlopoid snakes, including the highly specialized jaw mechanism. We argue that the key differences between the jaw mechanisms of Leptotyphlopidae, Anomalepididae, and Typhlopoidea provide compelling evidence for a strong role of convergence in the evolution of the scolecophidian bauplan, and these clades therefore cannot be interpreted as representative of ancestral anatomy or ecology among snakes.

Original languageEnglish
JournalJournal of Anatomy
Volume234
Issue number5
Pages (from-to)637-655
Number of pages19
ISSN0021-8782
DOIs
Publication statusPublished - 2019
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2019 Anatomical Society

    Research areas

  • comparative morphology, osteology, Scolecophidia, Typhlopoidea, Typhlops, Xenotyphlopidae

ID: 284287964