The Crocodylomorpha are an important group of archosaurs that include the living crocodilians and their extinct relatives.-1...

Evolutionary history

During Mesozoic and early Tertiary times the Crocodylomorpha were far more diverse than they are now. Triassic forms were small, lightly built, active terrestrial animals. These were supplanted during the early Jurassic by various aquatic and marine forms. The Later Jurassic, Cretaceous, and Tertiary saw a wide diversity of terrestrial and semi-aquatic lineages. "Modern" crocodilians do not appear until the Late Cretaceous. The Mesozoic is one of three geologic eras of the Phanerozoic eon. ...

Phylogenetic definition

The Crocodylomorpha are defined phylogenetically by Sereno 2005 as "The most inclusive clade containing Crocodylus niloticus (Laurenti 1768) but not Poposaurus gracilis Mehl 1915, Gracilisuchus stipanicicorum Romer 1972, Prestosuchus chiniquensis Huene 1942, Aetosaurus ferratus Fraas 1877." In biology, phylogenetics (Greek: phylon = tribe, race and genetikos = relative to birth, from genesis = birth) is the study of evolutionary relatedness among various groups of organisms (e. ... A clade is a term belonging to the discipline of cladistics. ... Binomial name Crocodylus niloticus (Laurenti, 1768) The Nile crocodile is the largest African crocodile and the top predator in its range, which covers most of Africa south of the Sahara, and the islands of Madagascar and Comoros. ... Poposaurus is the name given to a genus of reptile from the Late Triassic. ... Gracilisuchus (meaning graceful crocodile) is the name given to a tiny (30 cm long) genus of thecodont from the Triassic. ... This article or section does not cite its references or sources. ... Genera Aetosaurus Calyptosuchus Coahomasuchus Desmatosuchus Longosuchus Neoaetosauroides Paratypothorax Redondasuchus Stagonolepis Tecovasuchus Typothorax The Aetosaurs (family Stagonolepididae order Aetosauria) are an extinct clade of heavily armoured, medium to large sized, Late Triassic herbivorous archosaurs. ...

This a stem-based definition and therefore includes all taxa closer to extant crocodilians than to other crurotarsan clades. In palaeontology, a stem group is a systematic grouping that is required to accommodate fossils in the classification of organisms. ... Subtaxa Phytosauridae Prestosuchidae Ornithosuchidae Stagonolepididae Rauisuchidae Poposauridae Crocodylomorpha     Sphenosuchia     Crocodilia Crurotarsi (cross-ankles) is a node-based taxon created by Paul Sereno in 1991 to supplant the old term Pseudosuchia. ...

Taxonomy

The following classification is from the Bristol University webpage on Crocodylomorpha. All these taxa are extinct except for the three Eusuchian families shown here. There are in addition many other, less well-known groups that are not included in this current listing. Mikko's Phylogeny Archive provides a more detailed cladogram In biological classification, family (Latin: familia, plural familiae) is 1) a rank or 2) a taxon in that rank. ... Mikkos Phylogeny Archive is an amateur paleontology website maintained by Mikko Haaramo, a student at the University of Helsinkis Department of Geology, Division of Geology and Palaeontology. ... Greek clados = branch) or phylogenetic systematics is a branch of biology that determines the evolutionary relationships of living things based on derived similarities. ...

• Division ARCHOSAURIA
  • Superorder Crocodylomorpha
    • Family Saltoposuchidae
    • Family Sphenosuchidae
    • Order Crocodylia (Crocodyliformes)
      • Family Protosuchidae
      • Division Mesoeucrocodylia
        • Family Teleosauridae
        • Family Metriorhynchidae
        • Subdivision Metasuchia
          • Family Notosuchidae
          • Family Sebecidae
          • Infradivision Neosuchia
            • Family Goniopholidae
            • Family Dyrosauridae
            • Suborder Eusuchia
              • Family Gavialidae
              • Family Crocodylidae
              • Family Alligatoridae

-1... Subfamilies Family Crocodylidae    Crocodylinae    Alligatorinae    Gavialinae Crocodylia (or crocodylians) is an order of large reptiles that scientists believe branched off from class Reptilia about 220 million years ago. ... Mesoeucrocodylia is the name of the clade that has replaced the paraphyletic suborder Mesosuchia in phylogenetic taxonomy. ... Paleo Template Project The teleosaurids were marine crocodilians similar to the modern gharial. ... Paleo Template Project Metriorhynchids were a group of aquatic crocodilians that lived in seas during the Jurassic and Cretaceous periods. ... Binomial name Gavialis gangeticus (Gmelin, 1789) Taxonomy The Gharial (Gavialis gangeticus) is the only surviving member of the family Gavialidae, a long-established group of crocodile-like reptiles with long, narrow jaws. ... Genera Crocodylus Osteolaemus Tomistoma A crocodile can be any of the 14 species of large, water-loving reptiles in the family Crocodylidae (sometimes classified instead as the subfamily Crocodylinae). ... Genera Alligator Caiman Melanosuchus Paleosuchus Alligators and caimans are reptiles closely related to the crocodiles and forming the family Alligatoridae (sometimes regarded instead as the subfamily Alligatorinae). ...

References

• Benton, M. J. (2004), Vertebrate Palaeontology, 3rd ed. Blackwell Science Ltd
• Hay, O. P. 1930 (1929-1930). Second Bibliography and Catalogue of the Fossil Vertebrata of North America. Carnegie Institution Publications, Washington, 1,990 pp.
• Sereno, P. C. 2005. Stem Archosauria—TaxonSearch [version 1.0, 2005 November 7]
  • Taxon Search - Crocodylomorpha

Michael Benton is a professor of vertebrate palaeontology in the Department of Earth Sciences at the University of Bristol. ... Vertebrate Paleontology is a basic textbook on vertebrate paleontology by Michael Benton, published by the Blackwells. ... Front of the original Blackwells bookshop Blackwells is a national chain of publishers and bookshops in the United Kingdom. ... Paul C. Sereno (born October 11, 1967) is an American paleontologist who is the discoverer of several new dinosaur species on several continents. ...

External links

• Crocodylomorpha - webpages by Ross Elgin on the University of Bristol server
  • Major subgroups classification (used here)
• Crocodylomorpha from Palaeos
  • Technical definition
• Crocodylomorpha - hyperlinked cladogram at Mikko's Phylogeny Archive