DalinghesaurusLongidigitus-PaleozoologicalMuseumOfChina-May23-08

Shinisauria is a clade or evolutionary grouping of

anguimorph 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 propo ...

lizards that includes the living

Chinese crocodile lizard The Chinese crocodile lizard (''Shinisaurus crocodilurus'') is a semiaquatic anguimorph lizard found only in cool forests in southeast China and northeast Vietnam. The Chinese crocodile lizard spends much of its time in shallow water or in over ...

''Shinisaurus'' and several of its closest extinct relatives. Shinisauria was named in 2008 as a

stem-based taxon Phylogenetic nomenclature is a method of nomenclature for taxa in biology that uses phylogenetic definitions for taxon names as explained below. This contrasts with the traditional approach, in which taxon names are defined by a '' type'', which ...

to include all anguimorphs more closely related to ''Shinisaurus'' than to any other lizard. Several recent

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

analyses of lizard evolutionary relationships place Shinisauria in a basal position within the clade

Platynota Platynota is a polyphyletic group of anguimorph lizards and thus belongs to the order Squamata of the class Reptilia. Since it was named in 1839, it has included several groups, including monitor lizards, snakes, mosasaurs, and helodermatids. ...

, which also includes monitor lizards,

helodermatid ''Heloderma'' is a genus of toxicoferan lizards that contains five species, all of which are venomous. It is the only extant genus of the family Helodermatidae. Description The genus ''Heloderma'' contains the Gila monster (''H. suspectum'') ...

s, and the extinct

mosasaur Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Greek ' meaning 'lizard') comprise a group of extinct, large marine reptiles from the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on ...

s. Shinisaurians were once thought to be closely related to the genus '' Xenosaurus'', but they are now considered distant relatives within Anguimorpha. The fossil record of shinisaurians extends back to the Early Cretaceous with ''

Dalinghosaurus ''Dalinghosaurus'' (often incorrectly spelled "Dalinghesaurus") is an extinct genus of lizards, first described in 1998 by S.A. Ji of the Peking University Department of Geology. The type species is ''Dalinghosaurus longidigitus''.Ji, S.A. (1998 ...

'', which is from the Aptian aged

Yixian Formation The Yixian Formation (; formerly transcribed as Yihsien Formation) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the late Barremian and early Aptian stages of the Early Cretaceous. It is known for its exq ...

of China. Two other extinct shinisaurians are currently known: '' Bahndwivici'' from the

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...

of Wyoming and '' Merkurosaurus'' from the

Late Oligocene The Chattian is, in the geologic timescale, the younger of two ages or upper of two stages of the Oligocene Epoch/ Series. It spans the time between . The Chattian is preceded by the Rupelian and is followed by the Aquitanian (the lowest stage ...

of Germany and the

Early Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to ...

of the Czech Republic. An indeterminate shinisaurian is known from an isolated tail found in the Eocene aged

Messel pit The Messel pit (german: Grube Messel) is a disused quarry near the village of Messel (Landkreis Darmstadt-Dieburg, Hesse) about southeast of Frankfurt am Main, Germany. Bituminous shale was mined there. Because of its abundance of well-preserved ...

in Germany.

References

Anguimorpha Tetrapod unranked clades {{lizard-stub