| 词条 | Megaraptor |
| 释义 |
| name = Megaraptor | fossil_range = Late Cretaceous,[1] {{fossilrange|91|88}} | image = Megaraptor hand.jpg | image_caption = Reconstructed hand | genus = Megaraptor | parent_authority = Novas 1998 | species = namunhuaiquii | authority = Novas 1998 }}Megaraptor ("giant thief") is a genus of large theropod dinosaur that lived in the Turonian to Coniacian ages of the Late Cretaceous.[2][3] Its fossils have been discovered in the Patagonian Portezuelo Formation of Argentina. Initially thought to have been a giant dromaeosaur-like coelurosaur, it was classified as a neovenatorid allosauroid in previous phylogenies, but more recent phylogeny and discoveries of related megaraptoran genera has placed it as either a basal tyrannosauroid or a basal coelurosaur.[2] DescriptionMegaraptor was initially described as a giant dromaeosaur, known primarily from a single claw (about 30 cm long) that resembled the sickle-shaped foot claw of dromaeosaurids.[3] The discovery of a complete front limb, however, showed that this giant claw actually came from the first finger of the hand. In 2010, Gregory S. Paul estimated its length at {{convert|8|m|ft}}, its weight at {{convert|1|tonne|lbs}}.[4] The hands were unusually elongated, bearing sickle-shaped claws even more recurved than those of spinosaurids.[5]ClassificationThe hand is quite distinct from other basal tetanurans, so it was not initially clear whether Megaraptor was an allosaurid, a carcharodontosaurid, a spinosauroid, or something else entirely.[6] Subsequent studies, as well as the identification of close relatives with similar large claws on the forelimbs (see below), helped identify Megaraptor as a highly advanced and lightly built allosauroid, and a member of the family Neovenatoridae.[7] More recent studies have proposed that Megaraptor and its kin are actually tyrannosauroids[10] or spinosauroids[8] as opposed to allosauroids.[9] A juvenile specimen described in 2014 has provided more evidence towards Megaraptor being a primitive tyrannosauroid.[10] The discovery of Gualicho indicates that Megaraptor may not be a tyrannosauroid, but either an allosauroid or basal coelurosaur.[11] When first discovered and prior to publication, the spinosaurid Baryonyx was also reported to be a dromaeosaurid, and the allosauroid Chilantaisaurus was reported to be a possible spinosaurid, both based on the large hand claws. The cladogram shown below follows an analysis by Porfiri et al., 2014.[12] {{Clade/Megaraptora1|Megaraptora1=Aoniraptor}}== References == 1. ^Holtz, Thomas R. Jr. (2012) Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, Winter 2011 Appendix. 2. ^{{Cite web | url=https://www.paleowire.com/just-out-a-new-megaraptoran-theropod-dinosaur-from-the-upper-cretaceous-bajo-de-la-carpa-formation-of-northwestern-patagonia-cretaceous-research/ | title=Just out | A new megaraptoran theropod dinosaur from the Upper Cretaceous Bajo de la Carpa Formation of northwestern Patagonia @ Cretaceous Research}} 3. ^1 {{cite journal | last1 = Novas | first1 = F.E. | year = 1998 | title = Megaraptor namunhuaiquii, gen. et sp. nov., a large-clawed, Late Cretaceous theropod from Patagonia | url = | journal = Journal of Vertebrate Paleontology | volume = 18 | issue = | pages = 4–9 | doi = 10.1080/02724634.1998.10011030 }} 4. ^Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 99 5. ^Calvo, J.O., Porfiri, J.D., González-Riga, B.J., and Kellner, A.W. (2007) "A new Cretaceous terrestrial ecosystem from Gondwana with the description of a new sauropod dinosaur". Anais Academia Brasileira Ciencia, 79(3): 529-41.[https://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=pubmed&dopt=AbstractPlus&list_uids=17768539] 6. ^1 {{cite journal | last1 = Calvo | first1 = J. O. | last2 = Porfiri | first2 = J.D. | last3 = Veralli | first3 = C. | last4 = Novas | first4 = F.E. | last5 = Poblete | first5 = F. | year = 2004 | title = Phylogenetic status of Megaraptor namunhuaiquii Novas based on a new specimen from Neuquén, Patagonia, Argentina | url = | journal = Ameghiniana | volume = 41 | issue = | pages = 565–575 }} 7. ^{{cite journal | last1 = Benson | first1 = R.B.J. | last2 = Carrano | first2 = M.T | last3 = Brusatte | first3 = S.L. | year = 2010 | title = A new clade of archaic large-bodied predatory dinosaurs (Theropoda: Allosauroidea) that survived to the latest Mesozoic | url = | journal = Naturwissenschaften | volume = 97 | issue = 1| pages = 71–78 | doi = 10.1007/s00114-009-0614-x | pmid=19826771 | bibcode=2010NW.....97...71B}} 8. ^{{cite book|last=Holtz|first=T.R. Jr.|year=2012|title=Dinosaurs: The Most Complete, Up-to-date Encyclopedia for Dinosaur Lovers of All Ages|publisher=Random House Books for Young Readers|pages=95–96|isbn=978-0-375-82419-7}} 9. ^1 {{cite journal |author1=F. E. Novas |author2=F. L. Agnolín |author3=M. D. Ezcurra |author4=J. I. Canale |author5=J. D. Porfiri | year= 2012 | title=Megaraptorans as members of an unexpected evolutionary radiation of tyrant-reptiles in Gondwana | url=http://www.ameghiniana.org.ar/index.php/ameghiniana/article/view/868/1618 | journal=Ameghiniana | volume=49 | issue=Suppl | pages=R33 }} 10. ^{{cite journal | author=Porfiri, J. D., Novas, F. E., Calvo, J. O., Agnolín, F. L., Ezcurra, M. D. & Cerda, I. A.| year= 2014 | title=Juvenile specimen of Megaraptor (Dinosauria, Theropoda) sheds light about tyrannosauroid radiation |journal=Cretaceous Research| volume=51| pages=35–55 | doi=10.1016/j.cretres.2014.04.007| last2= Novas | last3= Calvo | last4= Agnolín | last5= Ezcurra | last6= Cerda }} 11. ^{{Cite journal | doi=10.1371/journal.pone.0157793| pmid=27410683| pmc=4943716|bibcode = 2016PLoSO..1157793A|title = An Unusual New Theropod with a Didactyl Manus from the Upper Cretaceous of Patagonia, Argentina| journal=PLOS ONE| volume=11| issue=7| pages=e0157793|last1 = Apesteguía|first1 = Sebastián| last2=Smith| first2=Nathan D.| last3=Juárez Valieri| first3=Rubén| last4=Makovicky| first4=Peter J.| year=2016}} 12. ^{{Cite journal|author1=Juan D. Porfiri |author2=Fernando E. Novas |author3=Jorge O. Calvo |author4=Federico L. Agnolín |author5=Martín D. Ezcurra |author6=Ignacio A. Cerda |year=2014 |title=Juvenile specimen of Megaraptor (Dinosauria, Theropoda) sheds light about tyrannosauroid radiation |journal=Cretaceous Research |volume=51 |pages=35–55 |doi=10.1016/j.cretres.2014.04.007 }} External links
9 : Megaraptorans|Coniacian life|Turonian life|Late Cretaceous dinosaurs of South America|Cretaceous Argentina|Fossils of Argentina|Portezuelo Formation|Fossil taxa described in 1998|Taxa named by Fernando Novas |
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