Asprosaurus
From Wikipedia, the free encyclopedia
| Asprosaurus Temporal range: Campanian | |
|---|---|
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| Line drawing of holotype specimen of A. bibongriensis, associated skull, jaw, axial, and appendicular elements | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Clade: | †Mosasauria |
| Superfamily: | †Mosasauroidea (?) |
| Genus: | †Asprosaurus Park, Evans & Huh, 2015 |
| Species: | †A. bibongriensis |
| Binomial name | |
| †Asprosaurus bibongriensis Park, Evans & Huh, 2015 | |
Asprosaurus (lit. 'white lizard') is an extinct genus of anguimorph lizard from the Late Cretaceous (Campanian) of South Korea. The genus contains a single species, A. bibongriensis, which is the first Mesozoic lizard to have been discovered on the Korean peninsula. Initially classified as a possible monstersaurian, Asprosaurus has been subsequently suggested to be a probable mosasauroid, an extinct group of marine lizards during the Late Cretaceous.
The holotype of Asprosaurus (KDRC-BB4) is an associated specimen consisting of partial cranial and postcranial material. Initially interpreted as a turtle fossil, it was discovered in 2000 from the Seonso Conglomerate, one of the rock units that form the Boseong Bibong-ri Dinosaur Egg Site which also yielded the fossils of an ornithischian dinosaur Koreanosaurus and over 200 dinosaur eggs.[2]
The generic name means "white lizard", named so because the fossil bones of the holotype were light in color, while Mesozoic fossil bones of the Korean peninsula are usually dark. The specific name is in reference to "bibongri", the type locality where the holotype was found. Because Asprosaurus is known only from fragmentary material, its relationships with other lizards are uncertain. However, features of the lower jaw suggest that it is an anguimorph, so the authors tentatively classified it as cf. Monstersauria, a clade which includes the living Gila monster.[2]
In 2016, a potential second specimen (KDRC-BB5) was identified as Asprosaurus sp. This specimen is a partial skull donated in 2008 from an uncertain stratigraphic level within the same locality where the holotype of Asprosaurus was discovered. The specimen exhibits synapomorphies of Varanoidea and Monstersauria, and is the only known lizard skull fossil with preserved teeth in South Korea.[3]
Description
Asprosaurus has an estimated skull length of 18–20 cm (7.1–7.9 in).[2] It is probably larger than Chianghsia,[4] whose skull length is estimated up to 17.5–18 cm (6.9–7.1 in) in total and the snout-vent length around 1–1.25 m (3 ft 3 in – 4 ft 1 in).[5] The jugal of Asprosaurus preserves an angulated orbital margin, but lacks osteoderms and differs in shape from that of the Chinese monstersaurian Zhongyuanxi.[6][7]
