Jacques Armand Gauthier (born June 7, 1948 in

New York City New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...

) is an American

vertebrate paleontologist Vertebrate paleontology is the subfield of paleontology that seeks to discover, through the study of fossilized remains, the behavior, reproduction and appearance of extinct animals with vertebrae or a notochord. It also tries to connect, by u ...

, comparative morphologist, and systematist, and one of the founders of the use of

cladistics Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...

in biology.

Life and career

Gauthier is the son of Edward Paul Gauthier and Patricia Marie Grogan. He received a B.S. degree in Zoology at

San Diego State University San Diego State University (SDSU) is a public research university in San Diego, California. Founded in 1897 as San Diego Normal School, it is the third-oldest university and southernmost in the 23-member California State University (CSU) system ...

in 1973, a Masters of Biological Science at the same institute in 1980, and a PhD in Paleontology from the

University of California The University of California (UC) is a public land-grant research university system in the U.S. state of California. The system is composed of the campuses at Berkeley, Davis, Irvine, Los Angeles, Merced, Riverside, San Diego, San Francisco, ...

, Berkeley, in 1984. Currently he is a Professor of Geology and Geophysics and Ecology and Evolutionary Biology and Curator of Vertebrate Paleontology and Vertebrate Zoology at

Yale University Yale University is a private research university in New Haven, Connecticut. Established in 1701 as the Collegiate School, it is the third-oldest institution of higher education in the United States and among the most prestigious in the wo ...

. His master's thesis, the content of which was published in 1982, is a classic work on the paleontology and phylogeny of the lizard clade

Anguimorpha The Anguimorpha is a suborder of squamates. The group was named by Fürbringer in 1900 to include all autarchoglossans closer to '' Varanus'' and ''Anguis'' than ''Scincus''. These lizards, along with iguanians and snakes, constitute the propos ...

that remains a core reference for morphological research on

Xenosauridae Xenosauridae is a family of anguimorph lizards whose only living representative is the genus ''Xenosaurus'', which is native to Central America. Xenosauridae also includes the extinct genera '' Exostinus'' and '' Restes''. Also known as knob-scal ...

and

Anguidae Anguidae refers to a large and diverse family of lizards native to the Northern Hemisphere. Common characteristics of this group include a reduced supratemporal arch, striations on the medial faces of tooth crowns, osteoderms, and a lateral fold ...

in particular. His PhD thesis constituted the first major

cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...

analysis of

Diapsida Diapsids ("two arches") are a clade of sauropsids, distinguished from more primitive eureptiles by the presence of two holes, known as temporal fenestrae, in each side of their skulls. The group first appeared about three hundred million years ago ...

, as well as arguing for the

monophyly In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic grou ...

of the

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s. He followed this with an important paper on the origin of

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

s from

theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...

s. This was the first detailed cladistic analysis of the theropod dinosaurs, and initiated a revolution in dinosaur

phylogenetics In biology, phylogenetics (; from Greek language, Greek wikt:φυλή, φυλή/wikt:φῦλον, φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary his ...

, in which cladistics replaced the Linnaean system in the

classification Classification is a process related to categorization, the process in which ideas and objects are recognized, differentiated and understood. Classification is the grouping of related facts into classes. It may also refer to: Business, organizat ...

and phylogenetic understanding of the dinosaurs. Gauthier's corpus contributed the foundational phylogenetic studies of Archosauria and

Lepidosauria The Lepidosauria (, from Greek meaning ''scaled lizards'') is a subclass or superorder of reptiles, containing the orders Squamata and Rhynchocephalia. Squamata includes snakes, lizards, and amphisbaenians. Squamata contains over 9,000 species ...

, two major amniote clades; and he was the primary author of the foundational and still widely cited phylogenetic study of

Amniota Amniotes are a clade of tetrapod vertebrates that comprises sauropsids (including all reptiles and birds, and extinct parareptiles and non-avian dinosaurs) and synapsids (including pelycosaurs and therapsids such as mammals). They are dis ...

as a whole. The phylogenetic character sets from his 1984 and 1986 works, the 1988 amniote paper, and the 1988 lepidosaur and

squamate Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest order of reptiles, comprising lizards, snakes, and amphisbaenians (worm lizards), which are collectively known as squamates or scaled reptiles. With over 10,900 species, ...

papers still form the core of essentially all gross-anatomy-based phylogenetic analyses of these groups, and as such are among the most highly cited papers in amniote morphology and paleobiology. The 1988 amniote paper is also frequently cited to demonstrate the importance of taxon sampling in phylogenetic analysis, in particular the importance of sampling rare or fossil taxa that can break 'long branches' along which convergence can occur. Gauthier has argued together with

Kevin de Queiroz Kevin de Queiroz is a vertebrate, evolutionary, and systematic biologist. He has worked in the phylogenetics and evolutionary biology of squamate reptiles, the development of a unified species concept and of a phylogenetic approach to biologica ...

for replacing

Linnaean taxonomy Linnaean taxonomy can mean either of two related concepts: # The particular form of biological classification (taxonomy) set up by Carl Linnaeus, as set forth in his ''Systema Naturae'' (1735) and subsequent works. In the taxonomy of Linnaeus t ...

with the

PhyloCode The ''International Code of Phylogenetic Nomenclature'', known as the ''PhyloCode'' for short, is a formal set of rules governing phylogenetic nomenclature. Its current version is specifically designed to regulate the naming of clades, leaving the ...

.Donoghue, Michael J., and Jacques A. Gauthier. "Implementing The Phylocode." ''Trends In Ecology & Evolution'' 19.6 (2004): 281-282. ''Academic Search Premier.'' Web. 11 Mar. 2013. In addition to his theoretical work on systematics and taxonomy, Gauthier continues to study the anatomy and relationships of diapsids, particularly lepidosaurs. His lizard work currently focuses on

Scincomorpha Scincomorpha is an infraorder and clade of lizards including skinks (Scincidae) and their close relatives. These include the living families Cordylidae (girdled lizards), Gerrhosauridae (plated lizards), and Xantusiidae (night lizards), as well ...

, following on a career-long interest in the unusual clade Xantusiidae. He is a principal investigator on the

National Science Foundation The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National I ...

-funded effort to reconstruct the phylogeny of lizards and snakes (

Squamata Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest order of reptiles, comprising lizards, snakes, and amphisbaenians (worm lizards), which are collectively known as squamates or scaled reptiles. With over 10,900 species, ...

) using gross anatomy and molecular structure, building on his earlier work in collaboration with Richard Estes and Kevin de Queiroz, which established the most widely accepted phylogeny of the group.

Footnotes

References

* (1988): Phylogenetic relationships within Squamata. ''In:'' : ''The Phylogenetic Relationships of the Lizard Families'': 15-98. Stanford University Press, Palo Alto. * (1982): Fossil xenosaurid and anguid lizards from the early Eocene of Wyoming, and a revision of the Anguioidea. ''Contributions to Geology, University of Wyoming'' 21: 7-54. * (1984): ''A cladistic analysis of the higher systematic categories of the Diapsida.'' hD dissertation Available from University Microfilms International, Ann Arbor, #85-12825, vii + 564 pp. * * (1988): A phylogenetic analysis of Lepidosauromorpha. ''In:'' : ''The Phylogenetic Relationships of the Lizard Families'': 15-98. Stanford University Press, Palo Alto. * * (1990): Ceratosauria. ''In:'' : ''The Dinosauria'': 151-168. University of California Press, Berkeley. * (1992): Phylogenetic taxonomy. '' Annu. Rev. Ecol. Syst.'' 23: 449–480. * (1994): The diversification of the amniotes. ''In:'' : ''Major Features of Vertebrate Evolution: Short Courses in Paleontology'': 129-159. Paleontological Society. *

External links

Yale Peabody Museum
{{DEFAULTSORT:Gauthier, Jacques American paleontologists American curators Phylogenetics researchers San Diego State University alumni University of California, Berkeley alumni Yale University faculty Science teachers American science writers Living people 1948 births