Untangling the dinosaur family tree

  title={Untangling the dinosaur family tree},
  author={Max Cardoso Langer and Mart{\'i}n Daniel Ezcurra and Oliver W. M. Rauhut and Michael J. Benton and Fabien Knoll and Blair Wayne McPhee and Fernando E Novas and Diego Pol and Stephen Louis Brusatte},
For over a century, the standard classification scheme has split dinosaurs into two fundamental groups1: ‘lizard-hipped’ saurischians (including meat-eating theropods and long-necked sauropodomorphs) and ‘bird-hipped’ ornithischians (including a variety of herbivorous species)2–4. In a recent paper, Baron et al.5 challenged this paradigm with a new phylogenetic analysis that places theropods and ornithischians together in a group called Ornithoscelida, to the exclusion of sauropodomorphs, and… 
Baron et al. reply
The morphological dataset underpinning the Ornithoscelida hypothesis is evaluated and the results of the new study differ so radically from all previous cladistic analyses, and decades of pre-cladistic research, that they deserve close scrutiny.
A paraphyletic ‘Silesauridae' as an alternative hypothesis for the initial radiation of ornithischian dinosaurs
Ornithischia changes from an obscure to a well-documented clade in the Triassic and is represented by records from Gondwana and Laurasia and was the first group of dinosaurs to adopt an omnivorous/herbivorous diet.
Taxon sample and character coding deeply impact unstable branches in phylogenetic trees of dinosaurs
The analysis nested ornithischians and theropods in a sister-group relationship, instead the traditional saurischian-ornithischia dichotomy, supporting the existence of the clade Ornithoscelida, which demonstrates how a single operational taxonomic unit can produces deep rearrangements on the branches of the phylogenetic tree of dinosaurs.
Increases in sampling support the southern Gondwanan hypothesis for the origin of dinosaurs
Dinosaurs were ubiquitous in terrestrial ecosystems through most of the Mesozoic and are still diversely represented in the modern fauna in the form of birds. Recent efforts to better understand the
The origin of Pterosaurs
  • M. Baron
  • Geography, Environmental Science
  • 2021
The phylogenetic nomenclature of ornithischian dinosaurs
The nomenclature of ornithischian dinosaur clades is revised; 76 preexisting ornithischerian clade names are revisited, their recent and historical use is reviewed, and their phylogenetic definitions are formally established.
Pisanosaurus mertii and the Triassic ornithischian crisis: could phylogeny offer a solution?
  • M. Baron
  • Geography, Environmental Science
  • 2019
Abstract Two recent studies have independently recovered Pisanosaurus mertii – long thought to represent the oldest known member of Ornithischia – within Silesauridae. These finds are expanded upon
A comprehensive anatomical and phylogenetic evaluation of Dilophosaurus wetherilli (Dinosauria, Theropoda) with descriptions of new specimens from the Kayenta Formation of northern Arizona
Many characters of the axial skeleton of Dilophosaurus wetherilli are derived compared to Late Triassic theropods and may be associated with macropredation and an increase in body size in Theropoda across the Triassic-Jurassic boundary.
Ingroup relationships of Lagerpetidae (Avemetatarsalia: Dinosauromorpha): a further phylogenetic investigation on the understanding of dinosaur relatives.
The phylogenetic analyses reveal that Lagerpetidae is one of the poorest known among the Triassic dinosauromorph groups in terms of their anatomy, so that new discoveries of more complete specimens are awaited to establish a more robust phylogeny.
New theropod dinosaur teeth from the Middle Jurassic of the Isle of Skye, Scotland
The Middle Jurassic is a largely mysterious interval in dinosaur evolution, as few fossils of this age are known worldwide. In recent years, the Isle of Skye has yielded a substantial record of


Early dinosaurs: A phylogenetic study
A new cladistic analysis of the early dinosaur radiation was performed to assess the relationships among the three major clades (Ornithischia, Sauropodomorpha and Theropoda) and to define the phylogenetic position of the basal members of the group.
A new hypothesis of dinosaur relationships and early dinosaur evolution
This study has found a sister-group relationship between Ornithischia and Theropoda (united in the new clade Ornithoscelida), with Sauropodomorpha and Herrerasauridae (as the redefined Saurischia) forming its monophyletic outgroup.
A new early dinosaur (Saurischia: Sauropodomorpha) from the Late Triassic of Argentina: a reassessment of dinosaur origin and phylogeny
The new evidence presented here demonstrates that dinosaurs first appeared in the fossil record as a diverse group, although they were a numerically minor component of faunas in which they occur.
Early ornithischian dinosaurs: the Triassic record
Abstract Ornithischian dinosaurs are one of the most taxonomically diverse dinosaur clades during the Mesozoic, yet their origin and early diversification remain virtually unknown. In recent years,
Phylogenetic reassessment of Pisanosaurus mertii Casamiquela, 1967, a basal dinosauriform from the Late Triassic of Argentina
The present analysis indicates that Pisanosaurus should be removed from the base of the Ornithischia and should no longer be considered the oldest representative of this dinosaurian clade.
The origin and early evolution of dinosaurs
The oldest unequivocal records of Dinosauria were unearthed from Late Triassic rocks accumulated over extensional rift basins in southwestern Pangea, and the group achieved a nearly global distribution by the latest Triassic, especially with the radiation of saurischian groups such as “prosauropods” and coelophysoids.
A Late Triassic dinosauriform from south Brazil and the origin of the ornithischian predentary bone
The South American Late Triassic offers the most comprehensive window to the early radiation of dinosaurs, enhanced by the discovery of Sacisaurus agudoensis, a new dinosauriform from the Caturrita Formation of Brazil, which has a pair of elements forming the tip of its lower jaw hypothesized to be equivalent to the ornithischian predentary.
A primitive ornithischian dinosaur from the Late Triassic of South Africa, and the early evolution and diversification of Ornithischia
Although the group played an important role in the evolution of Late Mesozoic terrestrial ecosystems, the early evolutionary history of the ornithischian dinosaurs remains poorly understood. Here, we
  • J. Dzik
  • Environmental Science, Geography
  • 2003
Abstract An accumulation of skeletons of the pre-dinosaur Silesaurus opolensis, gen. et sp. nov. is described from the Keuper (Late Triassic) claystone of Krasiejów in southern Poland. The strata are