''Tethysaurus'' 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 n ...

of tethysaurine mosasauroid from the Early

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded ...

(Late Cretaceous) period. The only species is ''Tethysaurus nopcsai''.

Discovery

The name means "Tethys' lizard of Nopcsa", a reference to the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

goddess A goddess is a female deity. In many known cultures, goddesses are often linked with literal or metaphorical pregnancy or imagined feminine roles associated with how women and girls are perceived or expected to behave. This includes themes of s ...

of the sea Tethys (also the name of the

Tethys Ocean The Tethys Ocean ( el, Τηθύς ''Tēthús''), also called the Tethys Sea or the Neo-Tethys, was a prehistoric ocean that covered most of the Earth during much of the Mesozoic Era and early Cenozoic Era, located between the ancient continents ...

, an ancient sea between southern Europe and northern Africa) and to the Hungarian paleontologist Baron

Ferenc Nopcsa Ferenc () is a given name of Hungarian origin. It is a cognate of Francis, Francisco, Francesco, François, Frank and Franz. People with the name include: * Ferenc Batthyány, Hungarian magnate and general * Ferenc Berényi, Hungarian artist * ...

, who made pioneering studies on Adriatic aquatic

squamate 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 ...

s. It was found in the Akrabou Formation, near the villages of Tadirhourst and Asfla in the region of

Goulmima Goulmima () is a town in Morocco situated in the province of Errachidia, in the region of Drâa-Tafilalet. An agricultural oasis, it is fed by the Wadi Gheris from the central High Atlas mountains. Like other settlements in Tafilalet, it was buil ...

Errachidia Province Errachidia ( Berber language: Imetɣaren) is a province located in eastern central Morocco in the region of Dra-Tafilalt. Errachidia is bordered by Algeria to the southeast and by the Moroccan provinces of Figig to the northeast, Midelt to the n ...

, in

Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria ...

, with three referred specimens that included a nearly complete articulated skull, mandible,

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characterist ...

e and portions of the

appendicular skeleton The appendicular skeleton is the portion of the skeleton of vertebrates consisting of the bones that support the appendages. There are 126 bones. The appendicular skeleton includes the skeletal elements within the limbs, as well as supporting shou ...

. The diagnosis after Bardet ''et al''. is "(...) prefrontal strongly vaulted in anterior view; parietal exhibits a triangular table ending posteriorly in two pointed pegs overlying the supraoccipital; jugal with a large and wide ascending ramus; medullar floor of the basioccipital pierced by three foramina; splenial with a large notched dorsomedial process; surangular exposed medially ventral to the coronoid; dental formula: 19-20 maxillary, 15-19 pterygoid and at least 19 dentary teeth; large paracotylar and parazygosphenal

foramina In anatomy and osteology, a foramen (;Entry "foramen"
in

on vertebrae."

Description

An average-sized mosasaur measuring long and weighing , ''Tethysaurus'' displays a number of

basal Basal or basilar is a term meaning ''base'', ''bottom'', or ''minimum''. Science * Basal (anatomy), an anatomical term of location for features associated with the base of an organism or structure * Basal (medicine), a minimal level that is nec ...

and

derived Derive may refer to: * Derive (computer algebra system), a commercial system made by Texas Instruments * ''Dérive'' (magazine), an Austrian science magazine on urbanism *Dérive, a psychogeographical concept See also * *Derivation (disambiguatio ...

features that led to an initial classification as an intermediate stage between primitive aigialosaurids of the Cenomanian and derived mosasaurids from the Turonian to the

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interv ...

. More recent analysis put ''Tethysaurus'' in a clade along '' Russellosaurus'' and '' Yaguarasaurus'' called the parafamily Russellosaurina, as a basal Turonian clade of Mosasauridae.

Phylogeny

Tethysaurus sclerotic eye ring prepared by Fossil Shack

Cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

based in the analysis by Makádi ''et al.'' in 2012:

References

External links

Oceans of Kansas

Paleobiology Database: Tethysaurus
Russellosaurins Mosasaurs of Africa Fossil taxa described in 2003 {{paleo-lizard-stub