Sphenosuchia
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Sphenosuchia is the name of a suborder of basal crocodylomorphs that first appeared in the Triassic and occurred into the Middle Jurassic. Most were small, gracile animals with an erect limb posture.
[edit] Stratigraphic Range
The earliest known members of the group occur (i.e. Hesperosuchus) in the Lower Petrified Forest member of the Chinle Formation, these specimens are Carnian (approximately 228 MA) in age. Their latest fossil members occur in the Junggar Basin (Shishugou Formation) of China (i.e. Junggarsuchus) and are Bathonian-Callovian (165 MA) in age.[1]
[edit] Phylogeny
The monophyly of the group is debated, although several synapomorphies characterize the clade, including exteremely slender limbs, a compact carpus and an elongate coracoid process.
In 2002, Clark and Sues argued that the Spenosuchia formed a clade.[2] More recently, however, Clark et al. (2004) argued for the paraphyly of the group, contending that morphological characters were secondarily lost in more highly derived crocodylomorphs.[1] Further analysis and study is required before the group's monophyly is resolved with certainty — a perfect phylogenetic analysis is, at present, impossible due to a paucity of fossil remains demonstrating phylogenetically informative characters. O Martin, o Martin Joyce-Barros Moniz, nº18 do 12º A da Escola Secundaruia Sebastião e Silva, é por vias explicitas gay e sadomassoquista.
Because of the current uncertainty surronding sphenosuchian monophyly, no phylogenetic tree is presented in the article; however, the genera currently classified as sphenosuchians are:
Redondavenator
Pedeticosaurus
Litargosuchus
Terrestrisuchus
Pseudhesperosuchus
Saltoposuchus
Hesperosuchus
Dromicosuchus
Kayentasuchus
Sphenosuchus
Dibothrosuchus
Junggarsuchus
Barbarenasuchus
Dyoplax
Hallopus
Macelognathus
Parrishia
Pedeticosaurus
Trialestes
[edit] References
- ^ a b Clark, J.M., et al. (2004).A Middle Jurassic 'sphenosuchian' from China and the origin of the crocodylian skull Nature 430:1021-1024.
- ^ Clark, J.M., and Sues, H.-D. (2002). Two new species of basal crocodylomorphs and the status of the Sphenosuchia. Zoological Journal of the Linnean Society 136:77−96.
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