Alvarezsauroidea

Alvarezsauroidea
Kladistiese klassifikasie
Koninkryk:	Animalia;
Filum:	Chordata;
Klade:	Dinosauria;
Klade:	Theropoda;
Klade:	Maniraptora;
Klade:	†Alvarezsauria;
Superfamilie:	†Alvarezsauroidea; (Bonaparte, 1991)

Alvarezsauroidea; Tydperk: Laat Jura-Laat Kryt, 160–65.5 m. jaar gelede PreЄ Є O S D C P T J K Pg N
	’n Gerekonstrueerde skelet van Mononykus olecranus.
Wetenskaplike klassifikasie
Koninkryk:	Animalia
Filum:	Chordata
Klas:	Sauropsida
Superorde:	Dinosauria
Orde:	Saurischia
Suborde:	Theropoda
Superfamilie:	†Alvarezsauroidea; (Bonaparte, 1991)
Tipespesie
	†Alvarezsaurus calvoi; (Bonaparte, 1991)
Subgroepe
	†Alnashetri; †Haplocheirus; †Alvarezsauridae

Alvarezsauroidea was ’n groep klein Maniraptora-dinosourusse. Die eerste fossiel is in die 1990's erken. Sedertdien het die getal vondste drasties toegeneem – die meeste is in China ontdek, maar ook in Noord- en Suid-Amerika en Europa.^[1] Hulle het van die Laat Jura to die Laat Kryt bestaan.

Die grootte van die Alvarezsauroidea-fossiele wissel van 0,5 tot 2 m, maar sommige lede kon groter gewees het.^[2] Die grootste lid was Haplocheirus. Vanweë dié dier se grootte en sy basale posisie, lyk dit of Alvarezsauroidea algaande kleiner geword het. Hoewel dit seldsaam is in dinosourusse, het dit ook in Paraves voorgekom.^[1]

Klassifikasie

Die presiese plek van Alvarezsauroid is steeds onseker. Eers is gedink dit is ’n sustergroep van Avialae (voëls) of deel van Avialae.^[1] Hulle is beskou as nie-vlieënde voëls^[3] omdat hulle baie soortgelyke eienskappe gehad het.^[1] Hierdie verwantskap is egter heroorweeg ná die vonds van primitiewe vorms soos Haplocheirus, Patagonykus en Alvarezsaurus, wat nie voëlagtige eienskappe toon nie.^[4]

Die diere se posisie is steeds omstrede. Hulle word binne Coelurosauria geplaas in Maniraptora of as ’n sustertakson van Ornithomimosauria binne Ornithomimiformes.

Verwysings

↑ ^1,0 ^1,1 ^1,2 ^1,3 Choiniere, J.N., Xu, X., Clark, J.M., Forster, C.A., Guo, Y. en Han, F. (2010). "A basal alvarezsauroid theropod from the early Late Jurassic of Xinjiang, China." Science, 327: 571-574. doi:10.1126/science.1182143 PMID 20110503
↑ Hutchinson, Chiappe (1998). "The first known alvarezsaurid (Theropoda: Aves) from North America". "Journal of Vertebrate Paleontology". 18(3): 447-450.
↑ Xu, X., Sullivan, C., Pittman, M., Choniere, J.N., Hone, D., Upchurch, P., Tan, Q., Xiao, D., Tan, L. en Han, F. (2011). "A monodactyl nonavian dinosaur and the complex evolution of the alvarezsauroid hand." PNAS, 108: no.6. doi:10.1073/pnas.1011052108/-/DCSupplemental
↑ Holtz, R.T. (2007). "Ornithomimosaurs and Alvarezsaurs". Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages. ISBN 978-0-375-82419-7.

Bronne

Nesbitt, S.J., Clarke, J.A., Turner, A.H., Norell, M.A. (2011): A small alvarezsauroid from eastern Gobi Desert offers insight into evolutionary patterns in the Alvarezsauroidea. Journal of Vertebrate Paleontology. 31:1. 144-153.
Turner, A.H., Nesbit, S.J., Norell, M.A. (2009): A Large Alvarezsaurid from the Late Cretaceous of Mongolia. American Museum Novitates. Number: 3648.
Bonaparte, J.F. (1991). "Los vertebrados fosiles de la formacion Rio Colorado, de la ciudad de Neuquen y Cercanias, Creatcio Superior, Argentina" Rev. Mus. Agent. Cienc. "Bernadino Rivadavia", Paleontol. 4:16-123.
Choiniere, J. (2010). Guest Post: Haplocheirus, the Skillful One Dave Hone's Archosaur Musings, April 23, 2011

[haplocheirus-1] 1,0 ^1,1 ^1,2 ^1,3 Choiniere, J.N., Xu, X., Clark, J.M., Forster, C.A., Guo, Y. en Han, F. (2010). "A basal alvarezsauroid theropod from the early Late Jurassic of Xinjiang, China." Science, 327: 571-574. doi:10.1126/science.1182143 PMID 20110503

[Chiappe1998-2] Hutchinson, Chiappe (1998). "The first known alvarezsaurid (Theropoda: Aves) from North America". "Journal of Vertebrate Paleontology". 18(3): 447-450.

[Xu2011-3] Xu, X., Sullivan, C., Pittman, M., Choniere, J.N., Hone, D., Upchurch, P., Tan, Q., Xiao, D., Tan, L. en Han, F. (2011). "A monodactyl nonavian dinosaur and the complex evolution of the alvarezsauroid hand." PNAS, 108: no.6. doi:10.1073/pnas.1011052108/-/DCSupplemental

[Holtz2007-4] Holtz, R.T. (2007). "Ornithomimosaurs and Alvarezsaurs". Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages. ISBN 978-0-375-82419-7.

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