Jacques Gauthier is a vertebrate paleontologist and systematist, and one of the founders of the use of cladistics in paleontology. Vertebrate paleontology seeks to discover the behavior, reproduction and appearance of extinct spined animals, through the study of their fossilized remains. ... This cladogram shows the relationship among various insect groups. ...

He received a BS in Zoology at San Diego State University in 1973, a Masters of SCience at the same institute in 1980, and a PhD in Paleontology from the University of California, Berkeley, in 1984. Currently he is Professor of Geology and Geophysics and Curator of Vertebrate Paleontology and Vertebrate Zoology at Yale University. His graduate thesis constituted the first major cladistic analysis of Diapsida, as well as arguing for the monophyly of the dinosaurs. San Diego State University athletics http://www. ... 1973 (MCMLXXIII) was a common year starting on Monday. ... The University of California (UC) is a public university system in the state of California. ... 1984 (MCMLXXXIV) was a leap year starting on Sunday of the Gregorian calendar. ... Yale redirects here. ... Greek clados = branch) or phylogenetic systematics is a branch of biology that determines the evolutionary relationships of living things based on derived similarities. ... Classes Ichthyosauria Sauropterygia Lepidosauria Archosauria Diapsids (two arches) are a group of tetrapod animals that developed two holes (temporal fenestra) in each side their skulls, about 300 million years ago during the late Carboniferous period. ... In phylogenetics, a group is monophyletic (Greek: of one stem) if all organisms in that group are known to have developed from a common ancestral form, and all descendants of that form are included in the group. ... Orders & Suborders Saurischia Sauropodomorpha Theropoda Ornithischia Thyreophora Ornithopoda Marginocephalia Dinosaurs were vertebrate animals that dominated the terrestrial ecosystem for over 160 million years, first appearing approximately 230 million years ago. ...

He followed this with an important paper (1986) on the origin of birds from theropods. This was the first detailed cladistic analysis of the theropod dinosaurs, and initiated a revolution in dinosaur phylogenetics, in which cladistics replaced the Linnaean system in the classification and phylogenetic understanding of the dinosaurs. Gauthier's 1984 and 1986 work still serve as basic references in modern cladistic analysis of the Diapsida and the Dinosauria. Orders Many - see section below. ... Families See text Theropods (beast foot) are a group of bipedal, primarily carnivorous dinosaurs, belonging to the saurischian (lizard-hip) family. ... In biology, phylogenetics (Greek: phylon = tribe, race and genetikos = relative to birth, from genesis = birth) is the study of evolutionary relatedness among various groups of organisms (e. ... Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms (as opposed to folk taxonomy). ...

More recently, Gauthier's has been applying cladistic methodology to the phylogeny of the Amniota, and argues for defining the tetrapods taxonomically as a crown clade only. Together with Kevin de Queiroz he argues for replacing the Linnaean taxonomy with the Phylocode Extant subgroups Synapsida     Mammalia (mammals) Sauropsida    Anapsida        Testudines (turtles)    Diapsida        Lepidosauria           Squamata (lizards and snakes)           Sphenodontida (tuatara)        Archosauria           Crocodilia (crocodiles and alligators)           Aves (birds) The amniotes are a group of vertebrates, comprising the mammals, birds, and various other groups collectively referred to as reptiles. ... Groups See text. ... Look up taxonomy in Wiktionary, the free dictionary. ... A crown group is a living monophyletic group or clade, consisting of the last common ancestor of all living examples, plus all of its descendants. ... Linnaean taxonomy classifies living things into a hierarchy, originally starting with kingdoms. ... Types of Clade (Note: Stem-based is now branch-based, to avoid confusion with the term stem group which means total clade minus crown clade.) The PhyloCode is a developing draft for a formal set of rules governing phylogenetic nomenclature. ...

Partial bibliography

• Gauthier, J., 1984. A cladistic analysis of the higher systematic categories of the Diapsida. [dissertation]. Available from University Microfilms International, Ann Arbor, #85-12825, vii + 564 pp.
• Gauthier, J., 1986. Saurischian monophyly and the origin of birds. In: K. Padian, ed. The Origin of Birds and the Evolution of Flight. Memoirs California Academy of Sciences 8. pp. 1–55
• Gauthier, J., R. Estes and K. de Queiroz, 1988. A phylogenetic analysis of Lepidosauromorpha. In: R. Estes and G. Pregill, eds. The Phylogenetic Relationships of the Lizard Families. Stanford University Press, Palo Alto. pp. 15–98.
• Gauthier, J., A. Kluge and T. Rowe, 1988. Amniote phylogeny and the importance of fossils. Cladistics 4(2):105–209.
• Rowe, T. and J. Gauthier, 1990. Ceratosauria. In: D. Weishample, P. Dodson and H. Osmolska, eds., The Dinosauria. University of California Press, Berkeley. pp. 151–168.
• de Queiroz, K. and J. Gauthier, 1992. Phylogenetic taxonomy. Annual Review of Ecology and Systematics 23:449–480.
• Gauthier, J.A., 1994. The diversification of the amniotes. In: D. Prothero, ed. Major Features of Vertebrate Evolution: Short Courses in Paleontology. Paleontological Society. pp. 129–159
• Donoghue, M.J. and J.A. Gauthier. 2004. Implementing the PhyloCode. Trends in Ecology & Evolution 19(6):281–282.

External links

• Yale Peabody Museum
• EvoWiki