''Cherminotus'' 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 ...

monitor lizard Monitor lizards are lizards in the genus ''Varanus,'' the only extant genus in the family Varanidae. They are native to Africa, Asia, and Oceania, and one species is also found in the Americas as an invasive species. About 80 species are rec ...

from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

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 ...

. The type and only species, ''Cherminotus longifrons'', was named in 1984.

Description and history

''Cherminotus longifrons'' was first described in 1984 from the

Barun Goyot Formation The Barun Goyot Formation (also known as Baruungoyot Formation or West Goyot Formation) is a geological formation dating to the Late Cretaceous Period. It is located within and is widely represented in the Gobi Desert Basin, in the Ömnögovi Pr ...

. More specimens were later found in the

Djadokhta Formation The Djadochta Formation (sometimes transcribed and also known as Djadokhta, Djadokata, or Dzhadokhtskaya) is a highly fossiliferous geological formation situated in Central Asia, Gobi Desert, dating from the Late Cretaceous period, about 75 mill ...

in localities such as Ukhaa Tolgod. ''Cherminotus'' is small for a monitor lizard and has a longer snout than its closest relative, the living

Earless monitor lizard The earless monitor lizard (''Lanthanotus borneensis'') is a semiaquatic, brown lizard native to the Southeast Asian island of Borneo. It is the only living species in the family Lanthanotidae and it is related to the true monitor lizards. Taxo ...

. ''Cherminotus'' is also very similar in appearance to ''

Aiolosaurus ''Aiolosaurus'' is an extinct genus of monitor lizard from the Late Cretaceous of Mongolia. The type and only species, ''Aiolosaurus oriens'', was named in 2000 from Ukhaa Tolgod, a rich fossil site in the Campanian-age Djadochta Formati ...

'', another monitor from the Cretaceous of Mongolia. Both monitors have a single hole in the

lacrimal bone The lacrimal bone is a small and fragile bone of the facial skeleton; it is roughly the size of the little fingernail. It is situated at the front part of the medial wall of the orbit. It has two surfaces and four borders. Several bony landmarks of ...

called the lacrimal foramen. Other monitors and monitor ancestors have two holes in the lacrimal, making the presence of only one hole in ''Cherminotus'' a case of evolutionary reversal.

References

Late Cretaceous lepidosaurs of Asia Cretaceous lizards Monitor lizards Prehistoric reptile genera Fossil taxa described in 1984 {{paleo-lizard-stub