Avian Ancestors: A Review of the Phylogenetic Relationships of the Theropods Unenlagiidae, Microraptoria, Anchiornis and Scansoriopterygidae

  title={Avian Ancestors: A Review of the Phylogenetic Relationships of the Theropods Unenlagiidae, Microraptoria, Anchiornis and Scansoriopterygidae},
  author={Federico Agnol{\'i}n and Fernando E. Novas},
  journal={Avian Ancestors},
Differential locomotor and predatory strategies of Gondwanan and derived Laurasian dromaeosaurids (Dinosauria, Theropoda, Paraves): Inferences from morphometric and comparative anatomical studies
The distinctive morphological evolutionary pathways of these two dromaeosaurid clades seem to have been influenced by the particular locomotor and predatory specializations that characterized each of these lineages. Expand
Feather Evolution in Pennaraptora
The origin and early evolution of complex feathers and flight abilities in paravian theropods were not linear processes, but more complex than previously thought. Expand
A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight
All parsimonious results support the hypothesis that each early paravian clade was plesiomorphically flightless, raising the possibility that avian flight originated as late as the Late Jurassic or Early Cretaceous. Expand
Assesment and interpretation of negative forelimb allometry in the evolution of non-avian Theropoda
It is proposed that proportionally longer arms of juveniles became adult traits in the small-sized and paedomorphic Aves, which suggests negative allometry of the forelimb in the ontogeny of most non-avian theropods. Expand
Paravian Phylogeny and the Dinosaur-Bird Transition: An Overview
It is concluded that troodontid affinities of anchiornithines, and dromaeosaurids affinITIES of microraptorians and unenlagiids are dismissed in favor of sister group relationships with Avialae, and main phylogenetic hypotheses that compete some topics about the non-avian dinosaur-bird transition are analyzed. Expand
Osteology of the unenlagiid theropod Neuquenraptor argentinus from the Late Cretaceous of Patagonia
Neuquenraptor argentinus was described as the first undoubted deinonychosaurian theropod from Gondwana. The only known specimen is represented by a fragmentary skeleton, including a nearly completeExpand
FANTASY VS REALITY: A Critique of Smith et al.'s Bird Origins
Adherents of the current orthodoxy of a derivation of birds from theropod dinosaurs, criticize the commentary by Feduccia and numerous papers by Lingham-Soliar using numerous mischaracterizations and misstatements of content, and illustrate their own misconceptions of the nature of the debate. Expand
A left frontal from the Upper Cretaceous Kirtland Formation (De-na-zin Member), San Juan Basin, New Mexico, is diagnosed as Saurornitholestes sullivani n. sp., a new species of dromaeosauridExpand
Reinterpretation of the Early Cretaceous maniraptoran (Dinosauria: Theropoda) Zhongornis haoae as a scansoriopterygid-like non-avian, and morphological resemblances between scansoriopterygids and basal oviraptorosaurs
Cladistic analysis confirms a close relationship between Zhongornis and Scansoriopterygidae, which share forelimbs and pedal unguals that are elongate compared to those of oviraptorosaurs, but does not support Oviraptorosaur affinities for this clade. Expand


An Archaeopteryx-like theropod from China and the origin of Avialae
It is demonstrated that many features formerly regarded as being diagnostic of Avialae, including long and robust forelimbs, actually characterize the more inclusive group Paraves (composed of the avialans and the deinonychosaurs), which challenges the centrality of Archaeopteryx in the transition to birds. Expand
Anatomy of Mahakala omnogovae (Theropoda: Dromaeosauridae), Tögrögiin Shiree, Mongolia
Several interesting features of Mahakala omnogovae have implications for deinonychosaurian and avialan character evolution and for understanding patterns of size variation and size change within paravian theropods. Expand
A short-armed dromaeosaurid from the Jehol Group of China with implications for early dromaeosaurid evolution
Recent discoveries of basal dromaeosaurids from the Early Cretaceous Jiufotang and Yixian formations of Liaoning, China, add significant new information about the transition from non-avian dinosaursExpand
Teeth with longitudinal grooves and ridges: absent
  • 2009
A new feathered dinosaur fossil that fills a morphological gap in avian origin
  • 2008
A Basal Dromaeosaurid and Size Evolution Preceding Avian Flight
Change in theropod body size leading to flight's origin was not unidirectional, and the two dinosaurian lineages most closely related to birds, dromaeosaurids and troodontids, underwent four independent events of gigantism, and in some lineages size increased by nearly three orders of magnitude. Expand
The tenth skeletal specimen of Archaeopteryx
The tenth skeletal specimen of the Upper Jurassic Archaeopterygidae is described and demonstrates the presence of a hyperextendible second toe in archaeopteryx, supporting previous assumptions that Archaeoperyx was only facultatively arboreal. Expand
Four-winged dinosaurs from China
New evidence is provided suggesting that basal dromaeosaurid dinosaurs were four-winged animals and probably could glide, representing an intermediate stage towards the active, flapping-flight stage of proavians. Expand
Deinonychosaurian fossils from the Jehol Group of western Liaoning and the coelurosaurian evolution. Dissertation for the doctoral degree
  • Chinese Academy
  • 2002
The theropod ancestry of birds: new evidence from the late cretaceous of madagascar
Rahona has a robust, hyperextendible second digit on the hind foot that terminates in a sicklelike claw, a unique characteristic of the theropod groups Troodontidae and Dromaeosauridae. Expand