A Review of Non-Mosasaurid (Dolichosaur and Aigialosaur) Mosasaurians and Their Relationships to Snakes

doi:10.1017/9781108938891.011

8 - A Review of Non-Mosasaurid (Dolichosaur and Aigialosaur) Mosasaurians and Their Relationships to Snakes

from Part II - Palaeontology and the Marine-Origin Hypothesis

Published online by Cambridge University Press: 30 July 2022

Bruno G. Augusta ,

Hussam Zaher ,

Michael J. Polcyn ,

Anthony R. Fiorillo and

Louis L. Jacobs

Edited by

David J. Gower and

Hussam Zaher

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David J. Gower: Affiliation:
Natural History Museum, London
Hussam Zaher: Affiliation:
Universidade de São Paulo

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Summary

Mosasaurian phylogenetics has been one of the most controversial topics in squamate systematics, with various studies and authors arguing in favor of a varanoid affinity (the Varanoid Hypothesis), a snake affinity (the Pythonomorph and Ophidiomorph Hypotheses) or only distant affinities to these lineages (the Stem-scleroglossan Hypothesis). We review the classification history of mosasaurians over the past two centuries, focusing on non-mosasaurid mosasaurians (dolichosaurs and aigialosaurs). A reappraisal is provided based on a new phylogenetic analysis. Our results clearly support the Varanoid Hypothesis. The Pythonomorph and Ophidiomorph Hypotheses are reviewed, and characters traditionally inferred to support these hypotheses are discussed and reinterpreted. Taxonomic sampling and fossil completeness likely play a major role—our (hopefully improved) phylogenetic hypothesis being based on denser taxon sampling and more complete character scoring resulting from additional studies, including the application of modern imaging techniques. Based on current data, our interpretation is that a particularly close phylogenetic relationship between mosasaurians and snakes can be rejected.

Keywords

morphology systematics phylogeny snakes marine Pythonomorpha mosasaurs fossils Aigialosauridae Dolichosauridae

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Type: Chapter
Information: The Origin and Early Evolutionary History of Snakes , pp. 157 - 179

DOI: https://doi.org/10.1017/9781108938891.011 [Opens in a new window]

Publisher: Cambridge University Press

Print publication year: 2022

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