Maniraptoriformes

Maniraptoriformes Temporal range: Late Jurassic–Recent,
Life restoration of Ornitholestes
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	Dinosauria
Order:	Saurischia
Suborder:	Theropoda
(unranked):	Maniraptoriformes Holtz, 1995
Subclades
Maniraptora Ornithomimosauria

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.

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. Epidendrosaurus and Pedopenna are known from the Daohugou Beds in China, whose age is still being debated, but may be about 160 Ma or 145 Ma.

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, but this now seems unlikely.

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. 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)

1 2 Harpymimus Deinocheirus Shenzhousaurus Pelicanimimus 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