| Hylaeochampsidae | |
|---|---|
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| Iharkutosuchus skull | |
Scientific 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 Andrews, 1913 |
| Genera | |
Hylaeochampsidae is an extinct family of basal eusuchian crocodylomorphs thought to be closely related to the order Crocodylia. [1]
Hylaeochampsidae was first constructed by Charles William Andrews in 1913 to include just one member: Hylaeochampsa . [2] However, a new genus named Iharkutosuchus was described in 2007 and was found to be a sister taxon of Hylaeochampsa, and thus a member of the family Hylaeochampsidae. The genus Heterosuchus , named in 1887, may also be a member of the family. [3] However, it is likely to be synonymous with Hylaeochampsa and has been considered a nomen dubium by James M. Clark and Mark Norell. Clark and Norell also claimed that there is no evidence to suggest that the two genera form a true clade distinct from other eusuchians, because remains associated with Heterosuchus are to fragmentary to show any clear phylogenetic relationship. [1] A fourth genus called Pietraroiasuchus was assigned to Hylaeochampsidae in 2011. A phylogenetic analysis conducted with the description of Pietraroiasuchus also found Pachycheilosuchus to be part of the family. [4] In this 2011 study, Buscalioni et al. cladistically defined Hylaeochampsidae as a node-based clade of the last common ancestor of Hylaeochampsa vectiana, Iharkutosuchus makadii, Pachycheilosuchus trinquei and Pietraroiasuchus ormezzanoi and all of its descendants. [4] [5]
The cladogram below results from the 2011 Buscalioni et al. study: [4]
| Eusuchia |
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The family existed during the Cretaceous period in what is now Europe and the Middle East. Hylaeochampsa and its possible synonym Heterosuchus have both been found from the Vectis Formation of the Isle of Wight in England, dating back to the Barremian stage of the Early Cretaceous. Specimens of Iharkutosuchus have been found from the Csehbánya Formation in western Hungary, which was deposited during the Santonian stage of the Late Cretaceous. All hylaeochampsids had highly brevirostrine snouts and exhibited heterodonty, with large teeth concentrated posteriorly that were most likely adapted to crushing. In Iharkutosuchus these teeth were even multicusped. This is often characteristic of mammals but is highly unusual for a crocodylomorph, and suggests that the animal may have been herbivorous. [6]
Yaverlandia is a genus of maniraptoran dinosaur. Known from a partial fossil skull found in Lower Cretaceous strata of the Wessex Formation on the Isle of Wight. it was described as the earliest known member of the pachycephalosaurid family, but research by Darren Naish shows it to have actually been a theropod, seemingly a maniraptoran. The type species is Y. bitholus.
Allodaposuchus is an extinct genus of crocodyliforms that lived in what is now southern Europe during the Campanian and Maastrichtian stages, and possibly the Santonian stage, of the Late Cretaceous. Although generally classified as a non-crocodylian eusuchian crocodylomorph, it is sometimes placed as one of the earliest true crocodylians. Allodaposuchus is one of the most common Late Cretaceous crocodylomorphs from Europe, with fossils known from Romania, Spain, and France.
Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. Extinct crocodylomorphs were considerably more ecologically diverse than modern crocodillians. The earliest and most primitive crocodylomorphs are represented by "sphenosuchians", a paraphyletic assemblage containing small-bodied, slender forms with elongated limbs that walked upright, which represents the ancestral morphology of Crocodylomorpha. These forms persisted until the end of the Jurassic. During the Jurassic, crocodylomorphs morphologically diversified into numerous niches, with the subgroups Neosuchia and the extinct Thalattosuchia adapting to aquatic life, while some terrestrial groups adopted herbivorous and omnivorous lifestyles. Terrestrial crocodylomorphs would continue to co-exist alongside aquatic forms until becoming extinct during the Miocene.
Pachycheilosuchus is an extinct genus of neosuchian from the Early Cretaceous of Texas, United States. Previously known, in part, as the "Glen Rose form", this crocodylomorph is notable for its procoelous vertebrae, otherwise found only in derived eusuchian crocodilians, a thick margin on the maxillae, and a shield of armor on the neck formed by the fusion of six individual scutes.
Eusuchia is a clade of neosuchian crocodylomorphs that first appeared in the Early Cretaceous, which includes modern crocodilians. Along with Dyrosauridae and Sebecosuchia, they were the only crocodyliformes who survived the K-Pg extinction.
Acynodon is an extinct genus of eusuchian crocodylomorph from the Late Cretaceous, with fossils found throughout Southern Europe.
Iharkutosuchus is an extinct genus of basal eusuchian crocodyliform. Its fossils have been found in the Santonian-age Upper Cretaceous Csehbánya Formation in the Bakony Mountains of western Hungary.
Eothoracosaurus is an extinct monospecific genus of eusuchian crocodylomorphs found in Eastern United States which existed during the Late Cretaceous period. Eothoracosaurus is considered to belong to an informally named clade called the "thoracosaurs", named after the closely related Thoracosaurus. Thoracosaurs in general were traditionally thought to be related to the modern false gharial, largely because the nasal bones contact the premaxillae, but phylogenetic work starting in the 1990s instead supported affinities within gavialoid exclusive of such forms. Even more recent phylogenetic studies suggest that thoracosaurs might instead be non-crocodilian eusuchians.
Heterosuchus is an extinct genus of crocodylomorph that may have been a eusuchian. It is known only from neck and back vertebrae recovered from Early Cretaceous-age rocks of the Hastings Beds of Hastings, Sussex. These vertebrae are procoelous, which is a trait of eusuchians. Heterosuchus was described by Harry Seeley in 1887, with H. valdensis as the type species. It may be the same genus as the slightly younger Hylaeochampsa, inferred to have been of similar evolutionary grade, but there is no overlapping material as Hylaeochampsa is known only from a partial skull; Hylaeochampsa would be the name used for both in that case, because it is the older name. Because of the sparse material and apparent lack of distinguishing characteristics, James Clark and Mark Norell (1992) considered Heterosuchus a dubious name.
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 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. Hylaochampsa was described by Richard Owen in 1874, with H. vectiana as the type species. 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. Hylaeochampsa is currently the oldest known unambiguous eusuchian.
Musturzabalsuchus is an extinct monospecific genus of allodaposuchid eusuchian crocodyliform. The type and only species is Musturzabalsuchus buffetauti.
Pholidosaurus is an extinct genus of neosuchian crocodylomorph. It is the type genus of the family Pholidosauridae. Fossils have been found in northwestern Germany. The genus is known to have existed during the Berriasian-Albian stages of the Early Cretaceous. Fossil material found from the Annero and Jydegård Formations in Skåne, Sweden and on the island of Bornholm, Denmark, have been referred to as a mesoeucrocodylian, and possibly represent the genus Pholidosaurus.
Shartegosuchidae is an extinct family of Late Jurassic and Early Cretaceous crocodyliforms. The family is named after the Late Jurassic Shar Teeg Beds in southwestern Mongolia, from which most shartegosuchid remains have been found. Five genera are currently assigned to Shartegosuchidae: Shartegosuchus, Nominosuchus, Kyasuchus, Adzhosuchus, and Fruitachampsa. Shartegosuchus, Nominosuchus, and Adzhosuchus all come from Shar Teeg, while Kyasuchus is known from the Early Cretaceous of Russia. Fruitachampsa is known from the Late Jurassic Morrison Formation of the western United States.
Shantungosuchus is an extinct genus of Early Cretaceous crocodyliform found in China. It includes three species: Shantungosuchus chuhsienensis and S. brachycephalus, which were both described by Yang Zhongjian – usually referred to as "Young" – in 1961 and 1982, and S. hangjinensis, which was described by Xiao-Chun Wu et al in 1994. S. chuhsienensis is the type for this genus.
Paluxysuchus is an extinct genus of neosuchian crocodyliform known from the Early Cretaceous Twin Mountains Formation of north-central Texas. It contains a single species, Paluxysuchus newmani. Paluxysuchus is one of three crocodyliforms known from the Early Cretaceous of Texas, the others being Pachycheilosuchus and an unnamed species referred to as the "Glen Rose Form". Paluxysuchus has a long, flat skull that is probably transitional between the long and narrow skulls of many early neosuchians and the short and flat skulls of later neosuchians.
Planocraniidae is an extinct family of eusuchian crocodyliforms known from the Paleogene of Asia, Europe and North America. The family was coined by Li in 1976, and contains three genera, Boverisuchus, Duerosuchus and Planocrania. Planocraniids were highly specialized crocodyliforms that were adapted to living on land. They had extensive body armor, long legs, and blunt claws resembling hooves, and are sometimes informally called "hoofed crocodiles".
Allodaposuchidae is an extinct clade of eusuchians that lived in Europe during the Late Cretaceous (Santonian-Maastrichtian).
Lohuecosuchus is an extinct genus of allodaposuchid eusuchian crocodylomorph that lived during the Late Cretaceous in what is now Spain and southern France.
Portugalosuchus is an extinct genus of eusuchian crocodyliform that was possibly a basal crocodylian – if so then it would be the oldest known crocodylian to date. The type species is P. azenhae, described in 2018, and it is known from the Late Cretaceous (Cenomanian)-aged Tentugal Formation in Portugal. A 2021 morphological study recovered Portugalosuchus within Crocodylia as a member of Gavialidae closely related to similar "thoracosaurs", while also noting that it might also possibly be outside of Crocodylia completely. A 2022 tip dating analysis incorporating both morphological and DNA data placed Portugalosuchus outside of Crocodylia, as the sister taxon of the family Allodaposuchidae. A cladogram simplified after that analysis is shown below:
Aprosuchus is a genus of small-bodied Maastrichtian atoposaurid Eusuchian from the Hateg Basin, Romania.
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