Biology:Crocodyliformes

Short description: Clade of reptiles

Crocodyliformes Temporal range: Late Triassic–Recent, 225–0 Ma PreЄ Є O S D C P T J K Pg N
Protosuchus, an early crocodyliform
Scientific classification
Missing taxonomy template (fix):	Archosauria/Reptilia
Clade:	Pseudosuchia
Clade:	Crocodylomorpha
Clade:	Solidocrania
Clade:	Crocodyliformes Hay, 1930
Clades
†Eopneumatosuchus †Junggarsuchus †Notochampsa †Orthosuchus †Pedeticosaurus? †Stegomosuchus? †Gobiosuchidae †Protosuchidae Mesoeucrocodylia Incertae sedis †Entradasuchus †Kemkemia †Microchampsa? †Tagarosuchus

Crocodyliformes is a clade of crurotarsan archosaurs, the group often traditionally referred to as "crocodilians". They are the first members of Crocodylomorpha to possess many of the features that define later relatives.

In 1988, Michael J. Benton and James M. Clark argued that all traditional names for well-known groups of animals should be restricted to their crown clades, that is, used only for natural groups comprising all living members of any given lineage. This posed a problem for the crocodilians, because the name Crocodylia, while used in various ways by various scientists, had always included not only living crocodilians but many of their extinct ancestors known only from the fossil record.

Benton and Clark's solution to this issue was to restrict the name Crocodylia to the group containing modern alligators, crocodiles, and gharials, plus any extinct members of those specific families. The traditional group "Crocodylia" was replaced by the name Crocodyliformes, which included many of the extinct families that the new definition left out. Clark and Benton did not initially provide an exact definition for Crocodyliformes; but, in 2001, Paul Sereno and colleagues defined it as the clade including Protosuchus richardsoni and the Nile crocodile, plus all descendants of their common ancestor.

Chris Brochu agreed with the assessment that Crocodylia as a name has never had stable contents, and that a series of clades larger than the crown group Crocodylia (including Crocodyliformes and the slightly more inclusive clade Crocodylomorpha) was a good solution. However, in a 2008 paper, Jeremy Martin and Benton reversed the previous opinion (co-authored by Benton) that Crocodylia should be restricted to the crown group, suggesting that Crocodyliformes should be considered a synonym of a more inclusive Crocodylia, and thus replaced. Brochu and colleagues rejected this proposal, arguing that the crown definition of Crocodylia is the standard meaning both within and beyond the crocodyliform systematics community.

Ecology

While all extant crocodilians are carnivorous, the ecological roles of Mesozoic crocodyliforms were more diverse, and included omnivory and herbivory. Herbivorous forms were present from the early Jurassic to the late Cretaceous and are thought to have evolved at least three times.

Fossil tracks

Tracks of a crocodyliform are known since Cretaceous, at least. Tracks representing the ichnofamily Batrachopodidae are described from the Early Cretaceous (late Aptian) Calonda Formation (Angola) by Mateus et al. (2017), who name a new ichnotaxon Angolaichnus adamanticus.

Phylogeny

Below is a simplified cladogram based on Fiorelli and Calvo (2007).

Crocodylomorpha	Terrestrisuchus     Dibothrosuchus      Crocodyliformes     Gobiosuchidae    Gobiosuchus     Zaraasuchus         Orthosuchus      Protosuchidae    Protosuchus     Hemiprotosuchus         "Kayenta Form"     Edentosuchus             Mesoeucrocodylia

In 2012, paleontologists Mario Bronzati, Felipe Chinaglia Montefeltro, and Max C. Langer conducted a broad phylogenetic analysis to produce supertrees of Crocodyliformes, including 184 species. The most parsimonious trees were highly resolved, meaning the phylogenetic relationships found in the analysis were highly likely. Below is a consensus tree from the study:

Kayentasuchus walkeri   Crocodyliformes Protosuchia   Orthosuchus stormbergi         Protosuchus richardsoni     Hemiprotosuchus leali         Kayenta Form     Edentosuchus tienshanensis               Zaraasuchus shepardi     Las Hoyas Croc     Gobiosuchus kielanae         Eopneumatosuchus colberti       Zosuchus davidsoni         Sichuanosuchus shuhanensis     Sichuanosuchus huidongensis         Shantungosuchus hangjinensis     Shantungosuchus chuhsiensis     Shantungosuchus brachycephalus     Neuquensuchus universitas               Shartegosuchus asperopalatum     Fruita Form (Fruitachampsa callisoni)           Hsisosuchus dashanpuensis     Hsisosuchus chungkingensis       Notosuchia     Araripesuchus wegeneri       Araripesuchus tsangatsangana     Araripesuchus buitreraensis       Araripesuchus patagonicus     Araripesuchus gomesii               Uruguaysuchus terrai     Uruguaysuchus aznarezi         Libycosuchus brevirostris       Simosuchus clarki         Malawisuchus mwakasyungutiensis     Candidodon itapecuruense           Notosuchus terrestris       Comahuesuchus brachybuccalis       Mariliasuchus amarali       Yacarerani boliviensis     Pakasuchus kapilimai     Adamantinasuchus navae               Stratiotosuchus maxhechti     Pehuenchesuchus enderi     Pabwehshi pakistanensis     Iberosuchus macrodon     Eremosuchus elkoholicus     Doratodon     Bergisuchus dietrichbergi     Baurusuchus salgadoensis     Baurusuchus pachechoi       Chimaerasuchus paradoxus       Sphagesaurus huenei     Sphagesaurus montealtensis             Sebecus huilensis     Sebecus icaeorhinus         Itaborai Croc     Bretesuchus bonapartei                         Anatosuchus minor         Barcinosuchus gradilis     Itasuchus jesuinoi       Miadanasuchus oblita     Trematochampsa taqueti     Caririsuchus camposi           Kaprosuchus saharicus     Mahajangasuchus insignis     Peirosauridae   Hamadasuchus rebouli       Montealtosuchus arrudacamposi     Uberabasuchus terrificus       Peirosaurus torminni     Lomasuchus palpebrosus               Neosuchia

References

Wikidata ☰ Q3003172 entry