''Janusaurus'' 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
ophthalmosaurid
Ophthalmosauridae is an extinct family of thunnosaur ichthyosaurs from the Middle Jurassic to the early Late Cretaceous (Bajocian - Cenomanian) worldwide. Almost all ichthyosaurs from the Middle Jurassic onwards belong to the family, until the ex ...
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
Upper Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987.
In European lithostratigraphy, the name ...
Slottsmøya
Member,
Agardhfjellet Formation of Central
Spitsbergen
Spitsbergen (; formerly known as West Spitsbergen; Norwegian: ''Vest Spitsbergen'' or ''Vestspitsbergen'' , also sometimes spelled Spitzbergen) is the largest and the only permanently populated island of the Svalbard archipelago in northern Norw ...
. The
holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...
consists of a partial
skull
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...
and postcrania, and would have belonged to an individual measuring long and weighing .
In 2019, ''Janusaurus'' was synonymized with ''
Arthropterygius'', though maintained as a separate species, by Nikolay Zverkov and Natalya Prilepskaya,
although this synonymy was objected to later that same year by Lene Delsett and colleagues, who maintained that they were sufficiently different to warrant separate genera.
Gallery
Janusaurus lundi.png, Restored skull
A-New-Upper-Jurassic-Ophthalmosaurid-Ichthyosaur-from-the-Slottsmøya-Member-Agardhfjellet-Formation-pone.0103152.s006.ogv, Video presentation
Keilhauia-1.png, Map of fossil locality
See also
*
List of ichthyosaurs
This list of ichthyosaurs is a comprehensive listing of all genera that have ever been included in the order Ichthyosauria or the parent clade Ichthyopterygia, excluding purely vernacular terms. The list includes all commonly accepted genera, but a ...
*
Timeline of ichthyosaur research
This timeline of ichthyosaur research is a chronological listing of events in the history of paleontology focused on the ichthyosauromorphs, a group of secondarily aquatic marine reptiles whose later members superficially resembled dolphins, shar ...
References
Ophthalmosaurinae
Ichthyosaurs of Europe
Late Jurassic ichthyosaurs
Late Jurassic reptiles of Europe
Tithonian life
Fossils of Svalbard
Agardhfjellet Formation
Fossil taxa described in 2014
Ichthyosauromorph genera
{{ichthyosaur-stub