Hylaeochampsa is an extinct genus of eusuchian crocodylomorphs. It is known only from a partial skull recovered from Barremian-age rocks of the Lower Cretaceous Vectis Formation (Wealden Group) of the Isle of Wight. This skull, BMNH R 177, is short and wide, with a eusuchian-like palate and inferred enlarged posterior teeth that would have been suitable for crushing.[2] Hylaochampsa was described by Richard Owen in 1874, with H. vectiana as the type species.[2] It may be the same genus as the slightly older Heterosuchus, inferred to have been of similar evolutionary grade, but there is no overlapping material as Heterosuchus is known only from vertebrae. If the two could be shown to be synonyms, Hylaeochampsa would have priority because it is the older name. Hylaeochampsa is the type genus of the family Hylaeochampsidae, which also includes Iharkutosuchus from the Late Cretaceous of Hungary. James Clark and Mark Norell positioned it as the sister group to Crocodylia.[3] Hylaeochampsa is currently the oldest known unambiguous eusuchian.[4]

Hylaeochampsa
Temporal range: Early Cretaceous: Barremian, 127.2–125 Ma[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauria
Clade: Pseudosuchia
Clade: Crocodylomorpha
Clade: Crocodyliformes
Clade: Metasuchia
Clade: Neosuchia
Clade: Eusuchia
Family: Hylaeochampsidae
Genus: Hylaeochampsa
Owen, 1874
Type species
Hylaeochampsa vectiana
Owen, 1874
Synonyms

The cladogram below results from a 2011 Buscalioni et al. phylogenetic study:[5]

Eusuchia

References edit

  1. ^ Rio, Jonathan P.; Mannion, Philip D. (6 September 2021). "Phylogenetic analysis of a new morphological dataset elucidates the evolutionary history of Crocodylia and resolves the long-standing gharial problem". PeerJ. 9: e12094. doi:10.7717/peerj.12094. PMC 8428266. PMID 34567843.
  2. ^ a b Owen, R. (1874). Monograph on the fossil Reptilia of the Wealden and Purbeck formations. Supplement no. V. Dinosauria (Iguanodon). [Wealden and Purbeck.]. The Palaeontographical Society, London 1873:1-18
  3. ^ Clark, James M.; Norell, Mark A. (1992). "The Early Cretaceous crocodylomorph Hylaeochampsa vectiana from the Wealden of the Isle of Wight" (PDF). American Museum Novitates (3032).
  4. ^ Brochu, Christopher A. (2003). "Phylogenetic approaches toward crocodylian history" (PDF). Annual Review of Earth and Planetary Sciences. 31 (31): 357–397. Bibcode:2003AREPS..31..357B. doi:10.1146/annurev.earth.31.100901.141308. S2CID 86624124. Archived from the original (PDF) on 2019-12-31.
  5. ^ Buscalioni, A.D.; Piras, P.; Vullo, R.; Signore, M.; Barbera, C. (2011). "Early eusuchia crocodylomorpha from the vertebrate-rich Plattenkalk of Pietraroia (Lower Albian, southern Apennines, Italy)". Zoological Journal of the Linnean Society. 163: S199–S227. doi:10.1111/j.1096-3642.2011.00718.x.