''Guanlingsaurus'' 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 shastasaurid

ichthyosaur Ichthyosaurs (Ancient Greek for "fish lizard" – and ) are large extinct marine reptiles. Ichthyosaurs belong to the order known as Ichthyosauria or Ichthyopterygia ('fish flippers' – a designation introduced by Sir Richard Owen in 1842, altho ...

from the

Late Triassic The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch ...

of China. It grew up to in length and has a wide, triangular skull with a short and toothless snout.

Discovery

It is known from a single species, ''Guanlingsaurus liangae'', that was found in the Carnian-age

Falang Formation Farang ( fa, فرنگ) is a Persian (and Southeast Asian) word that originally referred to the Franks (the major Germanic tribe) and later came to refer to White Europeans in general. The word "Farang" is a cognate and originates from Old F ...

of Guanling County, which is in the province of

Guizhou Guizhou (; formerly Kweichow) is a landlocked province in the southwest region of the People's Republic of China. Its capital and largest city is Guiyang, in the center of the province. Guizhou borders the autonomous region of Guangxi to t ...

. The genus and species were first named in 2000 on the basis of an incomplete adult skeleton. More complete skeletons were described in 2011, and a complete skeleton belonging to a juvenile was described in 2013. In 2011 ''Guanlingsaurus liangae'' was reassigned to the genus '' Shastasaurus'', which includes two species from North America that are known from more complete fossils than ''Guanlingsaurus''. However, the description of the juvenile specimen in 2013 revealed several features that make ''G. liangae'' distinct from ''Shastasaurus'' species, and the name was reinstated.

Description

The largest specimen of ''Guanlingsaurus'', YIGMR SPCV03109, measures long and weighs , while the juvenile specimen YIGMR SPCV03108 measures in length. In the largest specimen, YIGMR SPCV03109, the skull takes up 8.3% of the total body length, whereas it forms 9.3% in the juvenile specimen YIGMR SPCV03108. Both adult and juvenile specimens of ''Guanlingsaurus'' completely lack teeth and do not even possess a dental groove. The very short snout was highly compressed via a unique arrangement of skull bones. All bones of the snout tapered to abrupt points. In 2011, Sander and colleagues interpreted the

nasal bone The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face and by their junction, form the bridge of the upper one third of the nose. Eac ...

s (paired skull roof bones in the middle part of the skull) as extending to the very tip of the snout, a very unusual configuration for a reptile. However, Ji and colleagues did not find this feature.

Classification

Below is a cladogram from Fröbisch ''et al.'' (2013) showing ''Guanlingsaurus liangae'' as a species of ''Shastasaurus'':

References

Late Triassic ichthyosaurs Late Triassic reptiles of Asia Fossils of China Ichthyosauromorph genera {{Ichthyosaur-stub