Crocodylomorpha

Crocodylomorpha
Araripesuchus , skull
Temporal occurrence
Upper Triassic to this day
228 to 0 million years
Locations
Worldwide
Systematics
Sauropsida Diapsida Archosauromorpha Archosauria Crurotarsi Crocodylomorpha
Scientific name
Crocodylomorpha
Hay , 1930

The Crocodylomorpha have an extensive taxon of Archosauria or Avesuchia in which since the Upper Cretaceous proven crocodiles (Crocodylia) with their sometimes little crocodile-like appearance core group of representatives from the older Mesozoic are combined.

evolution

The earliest crocodylomorphs are the Saltoposuchidae and the Sphenosuchidae . They lived in the late Triassic and Lower Jurassic and were land-dwelling, 0.5 to 1.5 meters long, long-legged animals with an agile way of life and possibly able to keep their body temperature constant through metabolic activity ( endothermia ). Eventually the Saltoposuchidae could also have moved biped (only on the hind legs).

In the later evolution, with the development of the actual crocodiles, the animals changed to an aquatic way of life, developed into rather lazy ambulance hunters and became poikilothermic again because they had to use too much energy in the water for endothermia . The aquatic way of life reached its peak in the marine crocodiles ( Thalattosuchia ) of the Mesozoic Era . In the tertiary , some groups became terrestrial again . The 25 species of crocodiles that are still alive today are only a small remainder of what was once a large number of species (see also →  Tribal history of crocodiles ).

features

The early Crocodylomorpha share features of skull anatomy, particularly the location of the quadratum and squamosum , with the crocodiles. The skulls are massive and not kinetic, but pneumatic and strongly braced everywhere. In this way, very fast bites that are executed with great force can be caught. This enables feeding by particularly large prey animals. The skull windows are always small and overgrown in modern crocodiles. The jaw can be opened particularly wide, the powerful muscles attach to the rear end of the lower jaw.

Systematics

Family tree and fossil record of the Crocodylomorpha, from Kellner et al. (2014, first description by Sahitisuchus )

Systematics of the Crocodylomorpha, modified from Benton (2007):

• Crocodylomorpha
  • † Sphenosuchia
    • † Saltoposuchidae
    • † Sphenosuchidae
  • Crocodyliformes ^*
    • † Protosuchidae
    • Mesoeucrocodylia
      • † Thalattosuchia
        • † Teleosauridae
        • † Metriorhynchidae
      • Metasuchia
        • † Notosuchia
          • † Notosuchidae
          • † Chimaerasuchidae
          • † Comahuesuchidae
          • † Candidodontidae
          • † Sphagesauridae
          • † Baurusuchidae
          • † Uruguaysuchidae
        • † Sebecia
          • † Peirosauridae
          • † Sebecidae
        • Neosuchia
          • † Goniopholididae
          • † Pholidosauridae
          • † Bernissartia
          • Eusuchia
            • Crocodiles (Crocodylia) ^**
              • Gaviale (Gavialidae)
              • Real crocodiles (Crocodylidae)
              • Alligators (Alligatoridae)

Remarks

^*Since the Crodcodyliformes, in contrast to the Crocodylomorpha, only include representatives that can be described ecologically and morphologically in principle as "crocodiles", this taxon is still or again called "crocodylia" by some paleontologists today. Other paleontologists and especially biologists, however, understand “Crocodylia” only to be representatives of the Crocodylomorpha crown group .

^** Crocodylomorpha crown group

literature

• Michael J. Benton : Paleontology of the Vertebrates (translation of the 3rd English edition, translated by Hans-Ulrich Pfretzschner). Pfeil, Munich 2007, ISBN 3-89937-072-4
• Robert L. Carroll : Paleontology and Evolution of the Vertebrates. Thieme, Stuttgart 1993, ISBN 3-13-774401-6

Individual evidence

1. ↑ ^{a b} Adam Summers: Evolution: Warm-hearted crocs. Nature . Vol. 434, 2005, pp. 833-834, doi : 10.1038 / 434833a
2. ↑ ^{a b} R. S. Seymour, CL Bennett-Stamper, SD Johnston, DR Carrier, GC Grigg: Evidence for endothermic ancestors of crocodiles at the stem of archosaur evolution. Physiological and Biochemical Zoology. Vol. 77, No. 6 (Sixth International Congress of Comparative Physiology and Biochemistry Symposium Papers: Evolution and Advantages of Endothermy), 2004, pp. 1051-1067, doi : 10.1086 / 422766
3. ^ Alexander WA Kellner, André EP Pinheiro, Diogenes A. Campos: A New Sebecid from the Paleogene of Brazil and the Crocodyliform Radiation after the K-Pg Boundary. PLoS ONE. Vol. 9, No. 1, 2014, e81386, doi : 10.1371 / journal.pone.0081386
4. ↑ Jeremy E. Martin, Michael J. Benton: Crown Clades in Vertebrate Nomenclature: Correcting the Definition of Crocodylia. Systematic Biology. Vol. 57, No. 1, 2008, pp. 173-181, doi : 10.1080 / 10635150801910469

Web links

Commons : Crocodylomorpha  - Collection of images, videos and audio files

• University of Bristol Major subgroups of Crocodylomorpha
• Palæos Crocodylomorpha