''Leshansaurus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

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 ...

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 ...

from the

Late Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the ...

Shaximiao Formation The Shaximiao Formation () is a Middle to Late Jurassic aged geological formation in Sichuan, China, most notable for the wealth of dinosaurs fossils that have been excavated from its strata. The Shaximiao Formation is exposed in and around the ...

of what is now China. It was described in 2009 by a team of Chinese paleontologists. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

is ''Leshansaurus qianweiensis''. Fossils of ''Leshansaurus'' were discovered in strata from the

Shangshaximiao Formation The Shaximiao Formation () is a Middle to Late Jurassic aged geological formation in Sichuan, China, most notable for the wealth of dinosaurs fossils that have been excavated from its strata. The Shaximiao Formation is exposed in and around the ...

, a formation rich in dinosaur fossils. Li ''et al.'' referred this

taxon In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular n ...

Sinraptoridae Metriacanthosauridae is an extinct family of allosauroid theropod dinosaurs that lived from the Middle Jurassic to the Early Cretaceous. When broken down into its Greek roots, it means "moderately-spined lizards". The family is split into two su ...

– a group of

carnosauria Carnosauria is an extinct large group of predatory dinosaurs that lived during the Jurassic and Cretaceous periods. Starting from the 1990s, scientists have discovered some very large carnosaurs in the carcharodontosaurid family, such as '' G ...

n theropods,F. Li; Peng G.; Ye Y.; Jiang S.; and Huang, D. (2009). "A new carnosaur from the Late Jurassic of Qianwei, Sichuan, China". ''Acta Geologica Sinica'' 83(9): 1203–1213
Abstract
but it may belong to

Megalosauridae Megalosauridae is a monophyletic family of carnivorous theropod dinosaurs within the group Megalosauroidea. Appearing in the Middle Jurassic, megalosaurids were among the first major radiation of large theropod dinosaurs. They were a relatively ...

instead.

Discovery and naming

The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

(QW 200701) was found in 2007. It is a fairly complete skeleton consisting of a partial skull and lower jaws, seven cervical vertebrae, twelve dorsal vertebrae, five sacral vertebrae, two caudal vertebrae, and much of the hind limbs and hands. A second specimen (QW 200702), an isolated femur from a juvenile, has been designated as the

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). O ...

. ''Leshansaurus qianweiensis'' was named and described in 2009 by Li Fei,

Peng Guangzhao Peng may refer to: * Peng (surname) (彭), a Chinese name * Peng (state) (大彭), a state during the late Shang dynasty * Peng (mythology) (鵬), a legendary Chinese creature * ''Peng!'', 1992 album by Stereolab * ''PENG!'', a 2005 comic * P.Eng. ...

Ye Yong Ye or YE may refer to: Language * Ye (pronoun), a form of the second-person plural, personal pronoun "you" * The Scots word for "you" * A pseudo-archaic spelling of the English definite article (''the''). See '' Ye olde'', and the "Ye form" sect ...

Jiang Shan Jiang Shan (; born September 1962) is a former Chinese politician who spent most of his career in east China's Anhui province. As of April 2014 he was under investigation by the Communist Party's anti-corruption agency, and he was expelled from ...

, and Huang Daxi. The generic name refers to

Leshan Leshan, formerly known as Jiading or Jiazhou, is a prefecture-level city located at the confluence of the Dadu and Min rivers in Sichuan Province, China. Leshan is located on the southwestern fringe of the Sichuan Basin in southern Sichuan, ab ...

, a nearby city in

Sichuan Sichuan (; zh, c=, labels=no, ; zh, p=Sìchuān; alternatively romanized as Szechuan or Szechwan; formerly also referred to as "West China" or "Western China" by Protestant missions) is a province in Southwest China occupying most of th ...

, China, and the specific epithet refers to Qianwei, the county in which the fossils were found.

Description

''Leshansaurus'' was a medium-sized theropod that would have had a length of six to seven meters, and a hip height of about one and a half meters. ''Leshansaurus'' has an elongated skull that is broader towards the front. The femur has a length of 62 centimeters, and the tibia has a length of 52 centimeters. Its

autapomorphies In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to t ...

(unique characteristics) are the possession of a sharp central ridge on the supraoccipital (the bone above the occipital), elongated frontal bones that are 2.86 times as long as they are wide, slender basipterygoid projections on the basisphenoid, a bone of the lower braincase, an atlas intercentrum that is horseshoe-shaped in cross-section, slender diapophyses, thin spines of the dorsal vertebrae and sacral vertebrae, the possession of a clear keel at the bottom of the sacral vertebrae, and an ilium with on the inner side a distinct ridge along the edge of the hip joint.

Phylogeny

The describers placed ''Leshansaurus'' in the

, but they did not carry out a

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 ch ...

analysis. An analysis by Matthew Carrano in 2012 found it to be a member of the

megalosaurid Megalosauridae is a monophyletic family of carnivorous theropod dinosaurs within the group Megalosauroidea. Appearing in the Middle Jurassic, megalosaurids were among the first major radiation of large theropod dinosaurs. They were a relative ...

Afrovenatorinae, as

sister species In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

of ''

Piveteausaurus ''Piveteausaurus'' (meaning " Jean Piveteau's lizard") is a genus of theropod dinosaur known from a partial skull discovered in the Middle Jurassic Marnes de Dives formation of Calvados, in northern France and lived about 164.7-161.2 million y ...

'', a

known only from a braincase nearly identical to that of ''Leshansaurus''. The phylogenetic position of ''Leshansaurus'' according to Carrano ''et al.'' (2012) is shown by this cladogram:M.T. Carrano, R.B.J. Benson, and S.D. Sampson, 2012, "The phylogeny of Tetanurae (Dinosauria: Theropoda)", ''Journal of Systematic Palaeontology'' 10(2): 211-300

References

{{Taxonbar, from=Q1930219 Megalosaurs Middle Jurassic dinosaurs of Asia Fossil taxa described in 2009 Paleontology in Sichuan