''Arcanosaurus'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

varanoid Varanoidea is a superfamily of lizards, including the well-known family Varanidae (the monitors and goannas). Also included in the Varanoidea are the Lanthanotidae (earless monitor lizards), and the extinct Palaeovaranidae. Throughout their long ...

lizard from the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

of Spain. It is known from 29 vertebrae that were found

disarticulated In medical terminology, disarticulation is the separation of two bones at their joint, either traumatically by way of injury or by a surgeon during arthroplasty or amputation. See also * Joint dislocation * Acrotomophilia * Apotemnophilia * Amputa ...

but close together in a fossil locality called Viajete in the

province of Burgos The province of Burgos is a Provinces of Spain, province of northern Spain, in the northeastern part of the Autonomous communities of Spain, autonomous community of Castile-Leon, Castile and León. It is bordered by the provinces of Palencia (p ...

. The bones were found within a layer of the

Castrillo de la Reina Formation The Castrillo de la Reina Formation is a geological formation in Spain. It is late Barremian to early Aptian in age. It interpreted as a fluvial deposit. It primarily consists of red clay, with ribbon shaped sandstone channel fills. The rebbachisa ...

, which dates back to the late

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 125.77 Ma (million years ago) and 121.4 ± 1.0 Ma (Historically, this stage was placed at 129.4 million to approximately 125 million years ago) It is a ...

and early

Aptian The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...

stages of the Early Cretaceous. The vertebrae of ''Arcanosaurus'' share several features in common with those of other varanoid lizards, but they lack bony projections called posterior hypapophyses that are found in nearly all other varanoids.

References

Early Cretaceous reptiles of Europe Cretaceous lizards {{paleo-lizard-stub