''Luopingosaurus'' (meaning "Luoping lizard") is an extinct genus of

pachypleurosaurid left, 220px, '' Pachypleurosaurus'' Pachypleurosauria is an extinct clade of primitive sauropterygian reptiles that vaguely resembled aquatic lizards, and were limited to the Triassic period. They were elongate animals, ranging in size from , ...

sauropterygian Sauropterygia (" lizard flippers") is an extinct taxon of diverse, aquatic reptiles that developed from terrestrial ancestors soon after the end-Permian extinction and flourished during the Triassic before all except for the Plesiosauria bec ...

from the

Middle Triassic In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided in chronostratigraphy. The Middle Triassic spans the time between Ma and ...

Guanling Formation The Guanling Formation is a Middle Triassic (Anisian or Pelsonian in the regional chronostratigraphy) geologic formation in southwestern China. Description The formation encompasses two members. The first member is primarily calcareous mudston ...

Yunnan Province Yunnan , () is a landlocked province in the southwest of the People's Republic of China. The province spans approximately and has a population of 48.3 million (as of 2018). The capital of the province is Kunming. The province borders the C ...

, China. The genus contains a single species, ''L. imparilis'', known from a well-preserved, nearly complete skeleton.

Discovery and naming

The ''Luopingosaurus''

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 several ...

specimen,

IVPP The Institute of Vertebrate Paleontology and Paleoanthropology (IVPP; ) of China is a research institution and collections repository for fossils, including many dinosaur and pterosaur specimens (many from the Yixian Formation). As its name suggest ...

V19049, was discovered in sediments of the

, dated to the

Anisian In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic Ep ...

age (Pelsonian substage) of the middle

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

period, in

Luoping County Luoping County () is located in Qujing City, in eastern Yunnan province, China, bordering Guizhou province to the east and the Guangxi Zhuang Autonomous Region to the southeast. The county of Luoping in eastern Yunnan is noted for its springtim ...

, Yunnan Province, China. This specimen consists of a nearly complete,

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Th ...

ly-exposed,

articulated An articulated vehicle is a vehicle which has a permanent or semi-permanent pivot joint in its construction, allowing it to turn more sharply. There are many kinds, from heavy equipment to buses, trams and trains. Steam locomotives were someti ...

individual, lacking only the end of the tail. The preserved portion of the skeleton measures long. In 2023, Xu ''et al''. described ''Luopingosaurus imparilis'', a new genus and species of

, based on these fossil remains. The generic name, "''Luopingosaurus''", combines a reference to the type locality in Luoping County with the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

word "saurus", meaning "lizard". The specific name, "''imparilis''", means "peculiar" and "unusual" in

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

Description

''Luopingosaurus'' is one of the largest pachypleurosauroids, with an estimated total body length of . It also has an unusually long snout compared to other pachypleurosaurids; the only related taxon with a longer snout is ''

Wumengosaurus ''Wumengosaurus'' is an extinct aquatic reptile from the Middle Triassic (late Anisian stage) Guanling Formation of Guizhou, southwestern China. It was originally described as a basal eosauropterygian and usually is recovered as such by phy ...

'', which has occasionally been placed outside of

Pachypleurosauroidea left, 220px, '' Pachypleurosaurus'' Pachypleurosauria is an extinct clade of primitive sauropterygian reptiles that vaguely resembled aquatic lizards, and were limited to the Triassic period. They were elongate animals, ranging in size from , ...

by other authors. The evolution of this feature alongside the shorter-snouted

keichousaurids left, 220px, '' Pachypleurosaurus'' Pachypleurosauria is an extinct clade of primitive sauropterygian reptiles that vaguely resembled aquatic lizards, and were limited to the Triassic period. They were elongate animals, ranging in size from , ...

may have occurred due to differences in foraging and feeding specializations. The elongated snout may have allowed ''Luopingosaurus'' to more effectively catch and hold prey. ''Luopingosaurus'' represents the only known instance of hyperphalangy (an increase in the number of phalanges) in Pachypleurosauroidea, having five phalanges in the third digit as opposed to the

plesiomorphic In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, and ...

condition of four.

Classification

Xu ''et al''. (2023) recovered ''Luopingosaurus'' as a derived pachypleurosaurid member of the Pachypleurosauroidea, as the

sister taxon 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 t ...

to ''

Honghesaurus ''Honghesaurus'' is an extinct genus of pachypleurosaur from the Anisian-age Guanling Formation of China. The type specimen measures about in total body length. Classification The cladogram below follows Xu and colleagues (2022), when they use ...

''. Their results are shown in the

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

below:

References

{{Taxonbar, from=Q116041293 Pachypleurosaurs Triassic sauropterygians Guanling Formation Anisian genera Fossils of China Extinct animals of China Fossil taxa described in 2023 Prehistoric reptile genera