''Hoeckosaurus'' is an extinct

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 nom ...

of lizard from the Oligocene of

Mongolia Mongolia; Mongolian script: , , ; lit. "Mongol Nation" or "State of Mongolia" () is a landlocked country in East Asia, bordered by Russia to the north and China to the south. It covers an area of , with a population of just 3.3 million, ...

. It contains a single species, ''H. mongoliensis''. The genus name commemorates Austrian paleontologist Gudrun Höck, who collected the type material. ''Hoeckosaurus'' was a member of the

Dibamidae Dibamidae or blind skinks is a family of lizards characterized by their elongated cylindrical body and an apparent lack of limbs. Female dibamids are entirely limbless and the males retain small flap-like hind limbs, which they use to grip their ...

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

of primitive legless

squamates Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest order of reptiles, comprising lizards, snakes, and amphisbaenians (worm lizards), which are collectively known as squamates or scaled reptiles. With over 10,900 species, it ...

), and represents the only known fossil record of the Dibamidae, despite the presumed ancient origins of the group. Despite the close resemblance of the fossils to extant dibamids in the genera ''

Dibamus ''Dibamus'' is a genus of legless lizards in the family Dibamidae. Neang T, Holden J, Eastoe T, Seng R, Ith S, Grismer LL (2011). "A new species of ''Dibamus'' (Squamata: Dibamidae) from Phnom Samkos Wildlife Sanctuary, southwestern Cardamo ...

'' and '' Anelytropsis'', some distinguishing features such as an open Meckelian groove suggests that ''Hoeckosaurus'' is basal to both. The remains of ''Hoeckosaurus'' consist of some jawbones, and were collected in 1995-1997 from the Valley of the Lakes in central Mongolia. The sediments they were collected from are thought to be

Early Oligocene The Rupelian is, in the geologic timescale, the older of two ages or the lower of two stages of the Oligocene Epoch/ Series. It spans the time between . It is preceded by the Priabonian Stage (part of the Eocene) and is followed by the Chattian ...

in age. Previous studies postulated the jaws as belonging to an arretosaurid (an extinct family of Asian iguanians) or an

amphisbaenian Amphisbaenia (called amphisbaenians or worm lizards) is a group of usually legless squamates, comprising over 200 extant species. Amphisbaenians are characterized by their long bodies, the reduction or loss of the limbs, and rudimentary eyes. As ...

. However, a 2019 study identified the jaws as most closely resembling those of a dibamid, and assigned them to a new genus, ''Hoeckosaurus''.

References

{{Taxonbar, from1=Q108084490, from2=Q108081901 † Fossils of Mongolia Fossil taxa described in 2019 Prehistoric lizard genera