''Archosaurus'' (meaning "ruling lizard") is an extinct
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of carnivorous
proterosuchid
Proterosuchidae is an early family of basal archosauriforms whose fossils are known from the Latest Permian and the Early Triassic of Europe, Asia, Africa, Australia and possibly South America. The name comes from Greek πρότερο- ("first") ...
archosauriform
Archosauriformes (Greek for 'ruling lizards', and Latin for 'form') is a clade of diapsid reptiles that developed from archosauromorph ancestors some time in the Latest Permian (roughly 252 million years ago). It was defined by Jacques Gauthier ...
reptile
Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...
. Its fossils are dated to the
latest Permian of
Russia
Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
and
Poland
Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populous ...
, it is one of the earliest known archosauriforms. The type and only species is ''Archosaurus rossicus'', known from several fragmentary specimens which cumulatively represent parts of the skull and cervical vertebrae.
[Paleont. Zh. 1960 (4)] It would have been long when fully grown.
When first described in 1960, ''Archosaurus'' was considered the oldest known
archosaur
Archosauria () is a clade of diapsids, with birds and crocodilians as the only living representatives. Archosaurs are broadly classified as reptiles, in the cladistic sense of the term which includes birds. Extinct archosaurs include non-avian d ...
and a close relative of ''
Proterosuchus
''Proterosuchus'' is an extinct genus of archosauriform reptiles that lived during the Early Triassic. It contains three valid species: the type species ''P. fergusi'' and the referred species ''P. alexanderi'' and ''P. goweri''. All three spec ...
'' from the
Early Triassic
The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which is a un ...
.
[Tatarinov, L. P. (1960). ''Otkrytie pseudozhukhii v verkhnei permi SSSR: Paleontologischeskii Zhurnal'', 1960, n. 4, p. 74-80.] However, Archosauria in modern terms is considered a more restricted group which ''Archosaurus'' lies outside of. The "classic" definition of archosaur utilized prior to the widespread 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 ...
is now roughly equivalent to the clade Archosauriformes.
[Gauthier J. A. (1994): ''The diversification of the amniotes''. In: D. R. Prothero and R. M. Schoch (ed.) Major Features of Vertebrate Evolution: 129-159. Knoxville, Tennessee: The Paleontological Society.] ''Archosaurus'' is still considered the oldest undisputed archosauriform, as well as one of the few valid members of the family
Proterosuchidae
Proterosuchidae is an early family of basal archosauriforms whose fossils are known from the Latest Permian and the Early Triassic of Europe, Asia, Africa, Australia and possibly South America. The name comes from Greek πρότερο- ("first" ...
.
Gallery
File:Archosaurus rossicus.png, PIN 1100/55, the holotype left premaxilla
File:Archosaurus_ross1DB.jpg, Restoration
File:Archosaurus Scale.svg, Size comparison
See also
*''
Proterosuchus
''Proterosuchus'' is an extinct genus of archosauriform reptiles that lived during the Early Triassic. It contains three valid species: the type species ''P. fergusi'' and the referred species ''P. alexanderi'' and ''P. goweri''. All three spec ...
''
References
Fossils of Poland
Permian Russia
Permian reptiles of Europe
Prehistoric archosauriforms
Fossil taxa described in 1960
Prehistoric reptile genera
{{Permian-reptile-stub