''Xenodens'' (from Greek and

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

for "strange tooth") 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 marine lizard belonging to the

mosasaur Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Greek ' meaning 'lizard') comprise a group of extinct, large marine reptiles from the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on th ...

family. It currently contains a single species, ''X. calminechari'' (From

Arabic Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...

کالمنشار, meaning "like a saw"), which is known from Late

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 interval from ...

phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phospho ...

deposits in the Ouled Abdoun Basin,

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 to ...

. Its closest known relative is believed to be the durophagous ''

Carinodens ''Carinodens'' is an extinct genus of Cretaceous marine lizard belonging to the mosasaur family. "''Carinodens''" means "keel teeth" and was named in 1969 as a replacement name for ''Compressidens'', "compressed teeth", which was already in use ...

''. Estimated to have measured around in length, both the genus and

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

are named for the mosasaur's short and flattened blade-like teeth that collectively form a set of saw-like jaws. This is a feature that has never been seen in any other

tetrapod Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct theraps ...

but converge with the jaws of modern

dogfish sharks Squalidae, more commonly known as dogfish, dog sharks, or spiny dogfish, are one of several families of sharks categorized under Squaliformes, making it the second largest order of sharks, numbering 119 species across 7 families. Having earned t ...

and

piranha A piranha or piraña (, , or ; or , ) is one of a number of freshwater fish in the family Serrasalmidae, or the subfamily Serrasalminae within the tetra family, Characidae in order Characiformes. These fish inhabit South American rivers, ...

s. Based on the feeding behavior of these animals, paleontologists believe that ''Xenodens'' used its highly specialized dentition for a broad diet on

cephalopod A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

, and scavenged marine reptiles.

External links

This ancient sea reptile had a slicing bite like no other
''Xenodens calminechari'', with life-restoration. ''

Science News ''Science News (SN)'' is an American bi-weekly magazine devoted to articles about new scientific and technical developments, typically gleaned from recent scientific and technical journals. History ''Science News'' has been published since 1 ...

'', February 2, 2021
Xenodens, a weird shark-toothed mosasaur from Morocco- Nick Longrich

Dinosaur-era sea lizard had teeth like a shark

References

{{Mosasauridae Mosasaurines Mosasaurs of Africa Fossil taxa described in 2021