Species New to Science: Proceratosauridae

Showing posts with label Proceratosauridae. Show all posts

Friday, April 6, 2012

[Paleontology • 2010] Family Proceratosauridae: [a coelurosaur, a tyrannosauroid] • hylogenetic position of the theropod dinosaur Proceratosaurus bradleyi from the Middle Jurassic of England

Figure 1. Proceratosaurus bradleyi, type skull: NHM R 4860.

The cranial osteology of the small theropod dinosaur Proceratosaurus from the Bathonian of Minchinhampton, England, is described in detail, based on new preparation and computed tomography (CT) scan images of the type, and only known, specimen. Proceratosaurus is an unusual theropod with markedly enlarged external nares and a cranial crest starting at the premaxillary–nasal junction. The skull is highly pneumatic, with pneumatized nasals, jugals, and maxillae, as well as a highly pneumatic braincase, featuring basisphenoid, anterior tympanic, basipterygoid, and carotid recesses. The dentition is unusual, with small premaxillary teeth and much larger lateral teeth, with a pronounced size difference of the serrations between the mesial and distal carina. The first dentary tooth is somewhat procumbent and flexed anteriorly. Phylogenetic analysis places Proceratosaurus in the Tyrannosauroidea, in a monophyletic clade Proceratosauridae, together with the Oxfordian Chinese taxon Guanlong. The Bathonian age of Proceratosaurus extends the origin of all clades of basal coelurosaurs back into the Middle Jurassic, and provides evidence for an early, Laurasia-wide, dispersal of the Tyrannosauroidea during the late Middle to Late Jurassic.

Keywords: Bathonian; biogeography; Coelurosauria; phylogeny; Proceratosauridae; Tyrannosauroidea

Figure 2. Proceratosaurus bradleyi, type skull: NHM R 4860. Stereophotographs

Figure 24. Stratigraphic distribution and ghost lineages in basal coelurosaurs, especially tyrannosauroids.

Figure 26. Biogeographic distribution of Jurassic tyrannosauroids.

1, Proceratosaurus bradleyi, Great Oolite, England (Bathonian); Stokesosaurus langhami, Kimmeridge Clay, England (Tithonian); 2, Guanlong wucaii, Shishougou Formation, Xinjiang, China (Oxfordian); 3, Aviatyrannis jurassica, Guimarota Beds, Portugal (Kimmeridgian); 4, Stokesosaurus clevelandi, Morrison Formation, Utah, USA (Kimmeridgian–Tithonian).

Rauhut, O.W.M., Milner, A.C. and Moore-Fay, S. (2010). "Cranial osteology and phylogenetic position of the theropod dinosaur Proceratosaurus bradleyi (Woodward, 1910) from the Middle Jurassic of England". Zoological Journal of the Linnean Society. doi: 10.1111/j.1096-3642.2009.00591.x

Brusatte, S.L.; Norell, M.A.; Carr, T.D.; Erickson, G.M.; Hutchinson, J.R.; Balanoff, A.M.; Bever, G.S.; Choiniere, J.N.; Makovicky, P.J.; and Xu, X. (2010). "Tyrannosaur paleobiology: new research on ancient exemplar organisms". Science 329: 1481−1485. doi: 10.1126/science.1193304

https://sites.google.com/site/Brusatte/

[Paleontology • 2010] Kileskus aristotocus • A basal tyrannosauroid (Dinosauria: Theropoda) from the Middle Jurassic of Siberia, Russia

http://atrox1.ucoz.ru/photo/10-0-399-3

A.O. Averianov, S.A. Krasnolutskii and S.V. Ivantsov, 2010. A new basal coelurosaur (Dinosauria: Theropoda) from the Middle Jurassic of Siberia. Proceedings of the Zoological Institute RAS. Volume 314 (1): 42-57.

http://www.zin.ru/journals/trudyzin/doc/vol_314_1/TZ_314_1_Averianov.pdf

http://en.wikipedia.org/wiki/Kileskus

http://paleopedia.wikia.com/wiki/Kileskus

[Paleontology • 2009] Sinotyrannus kazuoensis • First large basal proceratosaurid theropod from the Early Cretaceous Jehol Biota in northeastern China

Sinotyrannus is a genus of proceratosaurid tyrannosauroid. Despite being not much younger than Dilong, another basal tyrannosaur, Sinotyrannus was very large in size (10 m), closer to that of Tyrannosaurus than Dilong.

Sinotyrannus is known from a single incomplete fossil specimen including a partial skull, from the Early Cretaceous Jiufotang Formation (app.120 million years ago) of Liaoning, China.

Ji, Q.; Ji, S.-A.; Zhang, L.-J. 2009. First large tyrannosauroid theropod from the Early Cretaceous Jehol Biota in northeastern China. Geological Bulletin of China 28 (10): 1369–1374.

http://xa.yimg.com/kq/groups/1225428/375768469/name/20091001.pdf

http://en.wikipedia.org/wiki/Sinotyrannus

http://paleopedia.wikia.com/wiki/Sinotyrannus

[Paleontology • 2006] Guanlong wucaii 'crown dragon' • A proceratosaurid tyrannosauroid dinosaur from the Late Jurassic of China

An artist rendering of Guanlong wucaii, the newly discovered basal tyrannosauroid, oldest known cousin of the Tyrannosaurus rex.

Credit: Zhang Zongda/IVPP

Guanlong wucaii skull | Photo Credit: IVPP

Guanlong wucaii skull rendering | Photo Credit: R.S. Li, IVPP

Theropoda Marsh, 1881

Coelurosauria von Huene, 1914

Tyrannosauroidea Osborn, 1905

Proceratosauridae Rauhut, Milner & Moore-Fay, 2010

Guanlong wucaii gen. et sp. nov.

Etymology. The generic name is derived from the Chinese Guan (crown) and long (dragon); the specific name is from the Chinese wucai (five colours), which refers to the rich colours of rocks that produced the specimens.

Holotype. IVPP (Institute of Vertebrate Paleontology and Paleoanthropology, Beijing) V14531 is a partly articulated skeleton preserving most of the elements.

Referred material. IVPP V14532 is much smaller than the holotype and is a fully articulated, nearly complete skeleton.

Locality and horizon. Wucaiwan area, Junggar Basin, Xinjiang; Oxfordian upper part of the Shishugou Formation.

Xu X., Clark, J.M., Forster, C. A., Norell, M.A., Erickson, G.M., Eberth, D.A., Jia, C., and Zhao, Q. 2006. A basal tyrannosauroid dinosaur from the Late Jurassic of China. Nature 439 (7077): 715–718. doi:10.1038/nature04511

'Crowned dragon': This reconstruction of the head of Guanlong wucaii is based on Xu and colleagues, the most notable feature being the crest, which may have been used in visual display.

(Drawing by Zhongda Zhang, reproduced by courtesy of the Institute of Vertebrate Paleontology and Paleoanthropology, Beijing.)

Guanlong wucaii in evolutionary context:

The bipedal and carnivorous theropod dinosaurs first appeared around 235 million years (Myr) ago in the Triassic period, later diverging into several different lines. In particular, during the Jurassic, one lineage (the Avetheropoda) divided into the Carnosauria and Coelurosauria, the latter including the Tyrannosauroidea. Certain primitive features of the two Guanlong fossils show that Guanlong lies at the base of the lineage of the tyrannosauroids, and close to the divergence between the major lineages of coelurosaurs. Numbers in parentheses indicate adult length.