Judeasaurus
Encyclopedia
Judeasaurus is an extinct genus
of small, aquatic
varanoid
lizard
related to the mosasaur
oids. The only known specimen is from the Late Cretaceous
of the Middle East
, though its exact provenance is uncertain.
and a number of cervical vertebrae
exposed in ventral view on a small slab of pink-grey limestone. The skull includes a fragmentary right maxilla
(with teeth), the co-ossified frontals
and parietal
s, right jugal
, postorbitofrontals, surpatemporals, squamosal
s, quadrates, the right dentary and fragmentary postdentary bones; the occipital
region of the skull is hidden beneath a calcareous
deposit. Some elements, such as the jugals, are preserved only as impressions. The skull is small, measuring only 60–70 millimeters in length.
and only known specimen (HUJI P4000, Hebrew University of Jerusalem
), though it was likely recovered from the Judea Group, either from the upper Laminated Limestone Member of the Kefar Sha'ul Formation (Upper Cenomanian
) or the lower member of the Bina Formation (Lower Turonian
), based on an examination of the lithology
of the limestone
matrix and planktonic fossil
foraminifera
preserved in the same slab.
of the species name honours Eitan Tchernov for his contributions to the paleontology
of Israel
.
Haber and Polcyn (2005, p. 249) diagnose Judeasaurus tchernovi as a varnoid lizard:
Haber and Polcyn (2005, 251-254) compare Judeasaurus with other marine varanoids (Adriosaurus and Pontosaurus), basal
mosasauroids (including Tethysaurus
, Haasiasaurus
, and Halisaurus
) and with members of the paraphyletic Aigialosaur
idae, and determined that Judeasaurus "represents a new taxon within Varanoidea, related to mosasauroids based on its fused frontals and circular quadrate." An affiliation with another group of Late Cretaceous marine varanoids, the Dolichosauridae, is proprosed but this relationship remains unresolved due to the poorly understood nature of dolichosaurs.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of small, aquatic
Aquatic animal
An aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, or directly through its skin. Natural environments and the animals that...
varanoid
Varanoidea
Varanoidea is a superfamily of lizards, including the well-known family Varanidae . Also included in the Varanoidea are such extinct marine and semi-aquatic forms as mosasaurs and dolichosaurs, the venomous helodermatids , the Lanthanotidae , and the extinct Necrosauridae.Throughout their long...
lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
related to the mosasaur
Mosasaur
Mosasaurs are large extinct marine lizards. The first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764...
oids. The only known specimen is from the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
of the Middle East
Middle East
The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...
, though its exact provenance is uncertain.
Description
The specimen consists of an incomplete but partly articulated skullSkull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
and a number of cervical vertebrae
Cervical vertebrae
In vertebrates, cervical vertebrae are those vertebrae immediately inferior to the skull.Thoracic vertebrae in all mammalian species are defined as those vertebrae that also carry a pair of ribs, and lie caudal to the cervical vertebrae. Further caudally follow the lumbar vertebrae, which also...
exposed in ventral view on a small slab of pink-grey limestone. The skull includes a fragmentary right maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
(with teeth), the co-ossified frontals
Frontal bone
The frontal bone is a bone in the human skull that resembles a cockleshell in form, and consists of two portions:* a vertical portion, the squama frontalis, corresponding with the region of the forehead....
and parietal
Parietal bone
The parietal bones are bones in the human skull which, when joined together, form the sides and roof of the cranium. Each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is named from the Latin pariet-, wall....
s, right jugal
Jugal
The jugal is a skull bone found in most reptiles, amphibians, and birds. In mammals, the jugal is often called the malar or Zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species....
, postorbitofrontals, surpatemporals, squamosal
Squamosal
The squamosal is a bone of the head of higher vertebrates. It is the principal component of the cheek region in the skull, lying below the temporal series and otic notch and bounded anteriorly by postorbital. Posteriorly, the squamosal articulates with the posterior elements of the palatal complex,...
s, quadrates, the right dentary and fragmentary postdentary bones; the occipital
Occipital
The word occipital, in zoology, pertains to the occiput .Occipital is a descriptor for several areas of animal & human anatomy.*External occipital protuberance* Internal occipital crest* Greater occipital nerve...
region of the skull is hidden beneath a calcareous
Calcareous
Calcareous is an adjective meaning mostly or partly composed of calcium carbonate, in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.-In zoology:...
deposit. Some elements, such as the jugals, are preserved only as impressions. The skull is small, measuring only 60–70 millimeters in length.
History
There is some doubt surrounding the provenance of the holotypeHolotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
and only known specimen (HUJI P4000, Hebrew University of Jerusalem
Hebrew University of Jerusalem
The Hebrew University of Jerusalem ; ; abbreviated HUJI) is Israel's second-oldest university, after the Technion – Israel Institute of Technology. The Hebrew University has three campuses in Jerusalem and one in Rehovot. The world's largest Jewish studies library is located on its Edmond J...
), though it was likely recovered from the Judea Group, either from the upper Laminated Limestone Member of the Kefar Sha'ul Formation (Upper Cenomanian
Cenomanian
The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding...
) or the lower member of the Bina Formation (Lower Turonian
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 93.5 ± 0.8 Ma and 89.3 ± 1 Ma...
), based on an examination of the lithology
Lithology
The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples or with low magnification microscopy, such as colour, texture, grain size, or composition. It may be either a detailed description of these characteristics or be a summary of...
of the limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
matrix and planktonic fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
foraminifera
Foraminifera
The Foraminifera , or forams for short, are a large group of amoeboid protists which are among the commonest plankton species. They have reticulating pseudopods, fine strands of cytoplasm that branch and merge to form a dynamic net...
preserved in the same slab.
Taxonomy and naming
The genus is named for the Judean Hills where the holotype of Judeasaurus tchernovi was discovered ("Judea lizard"), and the etymologyEtymology
Etymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...
of the species name honours Eitan Tchernov for his contributions to the paleontology
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
of Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
.
Haber and Polcyn (2005, p. 249) diagnose Judeasaurus tchernovi as a varnoid lizard:
Haber and Polcyn (2005, 251-254) compare Judeasaurus with other marine varanoids (Adriosaurus and Pontosaurus), basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
mosasauroids (including Tethysaurus
Tethysaurus
Tethysaurus was a genus of mosasaur from the Early Turonian period. The only species is Tethysaurus nopscai. The name means "Tethys' lizard of Nopsca", a reference to the Greek goddess of the sea Tethys and to the Hungarian paleontologist Baron Ferenc Nopsca, who made...
, Haasiasaurus
Haasiasaurus
Haasiasaurus is an extinct genus of mosasaur, originally named "Haasia" by M. J. Polcyn et al., in honour of the palaeontologist Georg Haas...
, and Halisaurus
Halisaurus
Halisaurus is an extinct genus of marine lizard belonging to the mosasaur family. With a length of 3–4 m , it was small compared to most other mosasaurs. It was named by Othniel Charles Marsh in 1869, but renamed Baptosaurus by Marsh in 1870, who thought the name was already in use by a fish...
) and with members of the paraphyletic Aigialosaur
Aigialosaur
Aigialosauridae is family of Late Cretaceous semi-aquatic varanoid lizards, regarded by some paleontologists to form distinct monophyletic group and by others as an adaptive grade within the basal mosasauroids....
idae, and determined that Judeasaurus "represents a new taxon within Varanoidea, related to mosasauroids based on its fused frontals and circular quadrate." An affiliation with another group of Late Cretaceous marine varanoids, the Dolichosauridae, is proprosed but this relationship remains unresolved due to the poorly understood nature of dolichosaurs.