Dinosauria ├─Ornithischia └─┬─Sauropodomorpha └─Theropoda │ └─Coelurosauria ├─Tyrannosauroidea └─┬─Ornithomimosauria └─┬─Maniraptora ├─Therizinosauroidea └─Metornithes ├─Alvarezsauridae └─┬─Oviraptorosauria └─Paraves ├─Deinonychosauria │ ├─Troodontidae │ └─Dromaeosauridae └─Avialae ├─Scansoriopterygidae └─Aves
Artwork by Matt Martyniuk, via Wikipedia, GNU Free Documentation/Creative Commons Attribution Share-alike
Introduction: Dromaeosaurs are considered dinosaurs, very close to the bird boundary (see The Mistaken Extinction). Greg Paul argues that they evolved from Archaeornithines -- the so-called "Secondary Flightlessness" (2F) hypothesis. For reasons which are not clear, this theory is very popular among educated amateurs, but finds little support among academic paleontologists. In either case, this shows how evolution is not about distinct types, but rather a gradation with countless intermediate stages.
These small to medium-sized predators were made famous through Hollywood fantasy. Everyone will remember them from Jurassic Park, Of course the Jurassic Park velociraptors were far larger than the typical species (two to three times the linear dimensions), scaly-skinned in a very un-maniraptoran reptilian manner, and, as befitting their cinematic black hatted villain role, had to be portayed as evil and menacing as possible. They were also able to turn door-knobs and open doors! [adapted from MAK, but with a different slant. AKW, revised MAK120307]
Dromaeosauridae =Deinonychosauria): Velociraptor, Utahraptor.
Range: Early Cretaceous to Late Cretaceous of North America, Japan & North China.
Phylogeny: Deinonychosauria : Troodontidae + *
Characters: Small (2-3m), lightweight predators. Interdental plates present but fused; tall, slender vertical process post to jaw articulation; brain fairly large; tail with thin anterior processes from pre-zaps & hemal arches (tail stiff, but not rigid); furcula present; ossified sternum; arms relatively long; "grasping" hand; pubis retroverted & parallel with ischium; short and unspecialized metatarsals; pes 2 with large raptorial claw, strongly curved and twice length of any other claw; probably feathered. Total mass perhaps 20 kg.
Links: DD: Dromaeosauridae; Dromaeosaurid Anatomy (excellent discussion of functional anatomy); Velociraptor skull) and Nakasato Virtual Museum Velociraptor (skull) (Nakasato); Fighting Dinosaurs (same); Bambiraptor Home; The Court Of B.feinbergi many detailed images of Bambiraptor); Dromaeosauridae; What is a Raptor?; The Fernleaf: Karen Carr; A New Dinosaur Specimen With Feather-like Structures; Pretty Butte Paleontology: Catalog of Dromaeosauridae Fossils; ???????? Dromaeosauridae; Re: Dromaeosauridae (was Troodontidae); DINOSAURS: Family Dromaeosauridae; dromaeosauridae; DROMAEOSAURIDAE German); Arts-Letters.com | Dino Database - Glossary; Deinonychosauria Dinosauricon); Deinonychosauria; ZOO-PAGE :: Dinosaorusi; Raptors; gaiaphyl.pdf; Feathered dinosaurs..
Image: Sinornithosaurus (reconstruction in Graves Museum by Brian Cooley) photograph by Michael Corriss (retouched by ATW) and reproduced by permission.
checkedATW040810, revised MAK120307