Maniraptoriformes

Holozoa

Maniraptoriformes Temporal range: Middle Jurassic–Recent, 160–0 Ma PreЄ Є O S D C P T J K Pg N Possible Early Jurassic record
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	Dinosauria
Order:	Saurischia
Suborder:	Theropoda
Branch:	Coelurosauria
Node:	Maniraptoriformes Holtz, 1995
Subgroups
Maniraptora †Ornithomimosauria
Synonyms
Bullatosauria Holtz, 1993 Ornithomimoidea Sereno, 1999

Maniraptoriformes is a clade of dinosaurs that contains ornithomimosaurs and maniraptors. This group was named by Thomas Holtz, who defined it as "the most recent common ancestor of Ornithomimus and birds, and all descendants of that common ancestor."

Fossil evidence

Many fossils have been discovered in recent years, particularly in China. Many of the feathered dinosaurs belong to this clade. In particular, a fossil of the Alvarezsauridae Shuvuuia has a version of keratin consistent with that of avian feathers.^[1]

Many nearly complete fossil maniraptoriforms are known from the late Jurassic. Archaeopteryx is known from Bavaria at 155-150 Ma. Ornitholestes, the troodontid WDC DML 110, Coelurus fragilis and Tanycolagreus topwilsoni are all known from the Morrison Formation in Wyoming at about 150 Ma. The Daohugou biota, including Anchiornis and Epidexipteryx, is the earliest record of maniraptoriformes, dating to about 160 Ma. One possible maniraptoriform, Eshanosaurus, lived even earlier, during the Early Jurassic, though its identification is controversial.^[2]

The wide range of fossils in the early Cretaceous and morphological evidence suggests that the main branches of maniraptoriform differentiation were separate before the end of the Jurassic.

Until recently, the relatives of Tyrannosaurus were thought to be maniraptoriforms,^[3] but this now seems unlikely.^[4][5]

History of study

In 1994,a study by paleontologist Thomas Holtz found a close relationship between the Ornithomimosauria and Troodontidae, and named this group Bullatosauria. Holtz rejected this hypothesis in 1999, and most paleontologists now consider troodontids to be much more closely related to either birds or Dromaeosauridae than they are to ornithomimosaurs, causing the Bullatosauria to be abandoned. The name referred to the inflated (bulbous) sphenoid both groups shared. Holtz defined the group as the clade containing the most recent common ancestor of Troodon and Ornithomimus and all its descendants.^[6] The concept is now considered redundant, and the clade Bullatosauria is now viewed as synonymous with Maniraptoriformes.

Classification

The following phylogenetic results are taken largely from Senter (2007)^[5]

1 2 †Harpymimus †Deinocheirus †Shenzhousaurus †Pelecanimimus †Garudimimus †Archaeornithomimus †Gallimimus †Struthiomimus †Anserimimus †Ornithomimus 3 †Ornitholestes 4 †Falcarius †Beipiaosaurus †Alxasaurus †Nanshiungosaurus 5 †Erliansaurus †Segnosaurus †Therizinosaurus 6 †Alvarezsaurus †Patagonykus †Mononykus †Shuvuuia 7+10

7 †Protarchaeopteryx †Avimimus †Caudipteryx 8 †Oviraptor †Citipati 9 †Ingenia 10 11 †Epidendrosaurus 12 †Archaeopteryx 13 †Jeholornis †Sapeornis †Confuciusornis †Enantiornithes †Yanornis †Hesperornis Modern Birds 14 15 †Sinovenator †Mei †Troodon 16 17 †Unenlagia 18 †Bambiraptor †Microraptor †Velociraptor †Deinonychus 19 †Dromaeosaurus

1 Maniraptoriformes, 2 †Ornithomimosauria, 3 Maniraptora, 4 †Therizinosauroidea, 5 Therizinosauridae, 6 †Alvarezsauridae, 7 †Oviraptorosauria, 8 †Oviraptoridae, 9 †Ingeniinae, 10 Paraves, 11 Avialae, 12 Aves, 13 Ornithurae, 14 †Deinonychosauria, 15 †Troodontidae, 16 †Dromaeosauridae, 17 †Unenlagiinae, 18 †Microraptoria, 19 †Dromaeosaurinae

See also

Coelurosauria
Maniraptora

References

1. ^ Schweitzer, M.H. (1999) http://www3.interscience.wiley.com/cgi-bibn/fulltext/63000744/PDFSTART
2. ^ Barrett, P.M. (2009). "The affinities of the enigmatic dinosaur Eshanosaurus deguchiianus from the Early Jurassic of Yunnan Province, People's Republic of China". Palaeontology 52 (4): 681–688. doi:10.1111/j.1475-4983.2009.00887.x. 
3. ^ Benton, 2004. http://palaeo.gly.bris.ac.uk/benton/vertclass.html
4. ^ Weishampel, 2004 The Dinosauria
5. ^ ^{a b} Senter, Phil (2007). "A NEW LOOK AT THE PHYLOGENY OF COELUROSAURIA (DINOSAURIA: THEROPODA)". Journal of Systematic Palaeontology 5 (4): 429. doi:10.1017/S1477201907002143. 
6. ^ Holtz, T.R. Jr (1994). "The phylogenetic position of the Tyrannosauridae. Implications for theropod systematics". Journal of Paleontology 68: 1100–1117.