Proterosuchidae (or Chasmatosuchidae) are an early, most certainly paraphyletic, assemblage of basal archosaurs whose fossils are known from the the Latest Permian of Russia and the Early Triassic of southern Africa, Russia, China, Australia, and Antarctica. They were slender, medium-sized (about 1.5 meters long), long-snouted and superficially crocodile-like animals, although they lack the armoured scutes of true crocodiles, and in their skeletal features are much more primitive. Their most characteristic feature is a distinct down-turning of the premaxilla (the front of the upper jaw, which overhangs the lower jaw). the limbs are short and indicate a sprawling posture, like contemporary lizards but unlike most later archosaurs. The Changhsingian (also known as Dorashamian, Dewey Lake, Changxingian, or Changshingian) is the second and final of two stages of the Lopingian epoch and the whole Permian period. ... The Olenekian (also known as the Yongningzhenian) is a stage of the Early Triassic epoch. ... Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms (as opposed to folk taxonomy). ... Phyla Subregnum Parazoa Porifera (sponges) Subregnum Agnotozoa Placozoa (trichoplax) Orthonectida (orthonectids) Rhombozoa (dicyemids) Subregnum Eumetazoa Radiata (unranked) (radial symmetry) Ctenophora (comb jellies) Cnidaria (coral, jellyfish, anemones) Bilateria (unranked) (bilateral symmetry) Acoelomorpha (basal) Orthonectida (parasitic to flatworms, echinoderms, etc. ... Typical Classes Subphylum Urochordata - Tunicatas Ascidiacea Thaliacea Larvacea Subphylum Cephalochordata - Lancelets Subphylum Myxini - Hagfishes Subphylum Vertebrata - Vertebrates Petromyzontida - Lampreys Placodermi (extinct) Chondrichthyes - Cartilaginous fishes Acanthodii (extinct) Actinopterygii - Ray-finned fishes Actinistia - Coelacanths Dipnoi - Lungfishes Amphibia - Amphibians Reptilia - Reptiles Aves - Birds Mammalia - Mammals Chordates (phylum Chordata) include the vertebrates, together with... Clades Subclass Anapsida Subclass Diapsida Infraclass Lepidosauromorpha Infraclass Archosauromorpha Sauropsida is an amniote clade that includes all recent and all or almost all extinct reptiles (excluding the Synapsida), and birds. ... Groups See Text Diapsids (two arches) are a group of tetrapod animals that developed two holes (temporal fenestra) in each side of their skulls, about 300 million years ago during the late Carboniferous period. ... Groups Order Rhynchosauria Order Trilophosauria Order Prolacertiformes Plesion     Archosauriformes Division        Archosauria Archosauromorpha (Greek for ruling reptiles form) are a diverse group or Infraclass of diapsid reptiles that first appeared during the late Permian, but only became common during the Triassic. ... Groups Proterosuchidae     Erythrosuchidae         Euparkeriidae             Archosauria Archosauriformes (Greek for ruling reptiles, + form) are a clade of diapsid reptiles that developed from Archosauromorph ancestors some time in the Late Permian (roughly 250 million years ago). ... Friedrich von Huene (March 22, 1875 – April 4, 1969) was a German paleontologist who named more dinosaurs in the early 20th century than anyone else in Europe. ... 1914 (MCMXIV) was a common year starting on Thursday. ... Paraphyletic - Wikipedia /**/ @import /skins-1. ... In phylogenetics, basal members of a group are subgroups that diverged very early from the others. ... Groups Archosaurus Chasmatosaurus Euparkeria Crurotarsi     Aetosauria     Crocodilia (crocodiles)     Phytosauria     Rauisuchia Ornithodira     Pterosauria     Marasuchus     Dinosauria        Aves (birds) Archosaurs (Greek for ruling reptiles) are a group of diapsid reptiles that first evolved from Archosauriform ancestors during the Olenekian (Lower Triassic). ... A scute (Latin scutum, shield) is a horny, chitinous, or bony external plate or scale, as on the shell of a turtle or the underside of a snake. ... The premaxilla is a pair of small bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. ... Families Many, see text. ...

The Proterosuchids represent perhaps the earliest adaptive radiation of the archosaurs. They gave rise to the Erythrosuchidae some time in the Early Triassic. Adaptive radiation describes the rapid speciation of a single or a few species to fill many ecological niches. ...

Taxonomy

• Infraclass Archosauromorpha
  • (unranked) Archosauriformes
    • Family Proterosuchidae
      • Archosaurus
      • Chasmatosuchus
      • Kalisuchus
      • Proterosuchus
      • Tasmaniosaurus

Groups Order Rhynchosauria Order Trilophosauria Order Prolacertiformes Plesion     Archosauriformes Division        Archosauria Archosauromorpha (Greek for ruling reptiles form) are a diverse group or Infraclass of diapsid reptiles that first appeared during the late Permian, but only became common during the Triassic. ... Groups Proterosuchidae     Erythrosuchidae         Euparkeriidae             Archosauria Archosauriformes (Greek for ruling reptiles, + form) are a clade of diapsid reptiles that developed from Archosauromorph ancestors some time in the Late Permian (roughly 250 million years ago). ... Chasmatosuchus was a large Thecodont reptile from the early Triassic period of South Africa and China. ...

References

• Benton, M. J. (2000), Vertebrate Paleontology, 2nd Ed.; (2004) 3rd edition Blackwell Science Ltd
• Carroll, R. L. (1988), Vertebrate Paleontology and Evolution, WH Freeman & Co.

Michael Benton is a professor of vertebrate palaeontology in the Department of Earth Sciences at the University of Bristol. ... Front of the original Blackwells bookshop Blackwells is a national chain of publishers and bookshops in the United Kingdom. ... Robert L. Carroll (b. ...

External links

• Proterosuchidae - at EvoWiki
• Proterosuchidae - list of species (Mikko's Phylogeny Archive)