Pythonomorpha

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Pythonomorphs
Temporal range:
Ma
Skull and jaws of Platecarpus, Peabody Museum of Natural History
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Clade: Toxicofera
Clade: Pythonomorpha
Cope, 1869
Subgroups

Pythonomorpha was originally proposed by

Mosasauridae (including Macrosaurus [?=Tylosaurus[1]], Mosasaurus, and Platecarpus
).

However, a close relationship between

synapomorphies
supporting Pythonomorpha.

If Pythonomorpha is valid, it contains not only mosasauroids but the Ophidiomorpha, which was defined as a node-based clade containing the most recent common ancestor of dolichosaurs, adriosaurs, Aphanizocnemus, and fossil and extant Ophidia and all of its descendants.[2]

However, the validity of Pythonomorpha is still debated; indeed, there is no consensus about the relationships of snakes or mosasaurs to each other, or to the rest of the lizards. An analysis by Conrad (2008) placed mosasaurs with varanoid lizards, and snakes with skinks, while an analysis by Gauthier et al. (2012) suggested that mosasaurs are more primitive than either snakes or varanoids. However, a combined morphological and molecular analysis by Reeder et al. (2015) recovered Mosasauria and Serpentes as sisters, consistent with Pythonomorpha.[3] A 2022 analysis found that mosasaurs were most closely related to Varanoidea, and stated that they "consider most characters previously reported as supporting the Pythonomorph Hypothesis to be problematic, because of incomplete fossil preparation, artefacts of taphonomy, limited comparisons, misinterpretations of anatomy, incomplete taxon sampling, or inadequate character formulation and/or scoring".[4]

References

  1. S2CID 86314572
    .
  2. doi:10.1671/0272-4634(2007)27[1:VFAAEI]2.0.CO;2
    .
  3. PMID 25803280
    .
  4. ISBN 978-1-108-93889-1
    , retrieved 2024-01-20

Further reading

  • Caldwell, M. W., Carroll, R. L. et Kaiser, H. 1995: The pectoral girdle and forelimb of Carsosaurus marchesetti (Aegialosauridae), with a preliminary phylogenetic analysis of Mosasauroids and varanoids. Journal of Vertebrate Paleontology 15(3): 516-531.
  • Caldwell, M. W. et Lee, M. S. Y. 1997. A snake with legs from the marine Cretaceous of the Middle East. Nature 386:705-709.
  • Caldwell, M. W. 1999. Squamate phylogeny and the relationships of snakes and mosasauroids. Zoological Journal of the Linnean Society 125:115-147.
  • Cope, E. D. 1869. On the reptilian orders Pythonomorpha and Streptosauria. Proceedings of the Boston Society of Natural History 12:250–266.
  • Lee, M. S. Y. 1997. The phylogeny of varanoid lizards and the affinities of snakes. Philosophical Transactions of the Royal Society of London B 352:53-91.
  • Lee, M. S. Y. et Caldwell, M. W.. 2000. Adriosaurus and the affinities of mosasaurs, dolichosaurs, and snakes. Journal of Paleontology 74(5):915-937.
  • Russell, D. A., 1967. Systematics and morphology of American mosasaurs. Peabody Museum of Natural History, Yale University, Bulletin 23.
  • Gauthier, J. A., Kearney, M., Maisano, J.A., Rieppel, O. et Behkke, A. D. B. 2012: Assembling the Squamate Tree of Life: Perspectives from the Phenotype and the Fossil Record. Bulletin of the Peabody Museum of Natural History 53(1):3-308.
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