Silesauridae

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Silesauridae
Temporal range: Middle TriassicLate Triassic, 245–203 Ma
Silesaurus1.jpg
Life restoration of a Silesaurus
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Dinosauriformes
Clade: Silesauridae
Langer et al., 2010

Silesauridae is an extinct clade of dinosauriformes, a group of Triassic reptiles which included early ancestors and relatives of the dinosaurs. The silesaurids were a sister group to the dinosaurs. The group was named in 2010 by paleontologist Max C. Langer et al. They defined it as a branch-based clade of all archosaurs closer to Silesaurus opolensis than to either Heterodontosaurus tucki or Marasuchus lilloensis. At the same time, a second group of scientists independently named Silesauridae as a node-based clade consisting of Lewisuchus, Silesaurus, their last common ancestor and all their descendants.[1] Currently, both definitions encompass the same group of animals. In a later paper, Sterling J. Nesbitt et al. (2010) noted that the earlier definition by Langer et al. did not include a diagnosis, and so was not sufficient to create a ranked family-level name according to the ICZN. Therefore, the family Silesauridae is attributed to Nesbitt et al. (2010) while the clade Silesauridae is attributed to Langer et al. (2010)[2]

The fossils range in age from the Anisian to the Norian stages of the Triassic, about 245 to 203 million years ago.[1][3] The members of Silesauridae are Silesaurus, Eucoelophysis, Lewisuchus (Pseudolagosuchus), Agnosphitys, Sacisaurus, Diodorus, Asilisaurus, Lutungutali, Technosaurus and Ignotosaurus. The cladogram below follows the phylogenetic analysis of basal ornithodirans conducted by Christian Kammerer, Sterling Nesbitt and Neil Shubin (2012).[2]

Ornithodira 

Pterosauria


 Dinosauromorpha 
 Lagerpetonidae 

Lagerpeton chanarensis




Dromomeron gregorii



Dromomeron romeri




 Dinosauriformes 

Marasuchus lilloensis




Dinosauria


 Silesauridae 

Lewisuchus/Pseudolagosuchus




Asilisaurus kongwe




Eucoelophysis baldwini




Silesaurus opolensis




Sacisaurus agudoensis



Diodorus scytobrachion











A large phylogenetic analysis of early dinosaurs and dinosauromorphs carried out by Matthew Baron, David Norman and Paul Barrett (2017) and published in the journal Nature recovered Silesauridae as a monophyletic sister group to Dinosauria. The study also recovered the taxon Agnosphitys within the clade Silesauridae, close to Lewisuchus and its synonymous taxon Pseudolagosuchus.[4]

References[edit]

  1. ^ a b Nesbitt, Sterling J., Sidor, Christian A., Irmis, Randall B., Angielczyk, Kenneth D., Smith, Roger M.H. and Tsuji, Linda A. (2010) "Ecologically distinct dinosaurian sister group shows early diversification of Ornithodira." Nature 464(7285):95-8 Supplement
  2. ^ a b Kammerer, C. F.; Nesbitt, S. J.; Shubin, N. H. (2012). "The First Silesaurid Dinosauriform from the Late Triassic of Morocco". Acta Palaeontologica Polonica. 57 (2): 277. doi:10.4202/app.2011.0015. 
  3. ^ Langer, M.C., Ezcurra, M.D., Bittencourt, J.S., and Novas, F.E. (2010). "The origin and early evolution of dinosaurs". Biological Reviews 85:55-110. doi:10.1111/j.1469-185X.2009.00094.x
  4. ^ Baron, M.G., Norman, D.B., and Barrett, P.M. (2017). A new hypothesis of dinosaur relationships and early dinosaur evolution. Nature, 543: 501–506. doi:10.1038/nature21700

External links[edit]