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 for a gadilidan scaphopod mollusk.[1]
Carinodens is widely considered a sister taxon to Globidens classified within the tribe Globidensini. Like its close relative, Carinodens also possesses distinctive round, blunt teeth for crushing primitive clams and oysters. Most of the cranial elements known from the genus have been recovered from deposits in the Netherlands and Belgium, with the only known postcranial material being known from deposits of latest Maastrichtian age in Jordan.[2][3] Other materials have been discovered in Brazil, Morocco, Russia, Ukraine and Denmark.[3][4]
Carinodens measured about 2–2.6 metres (6.6–8.5 ft) in length and is one of the smallest known mosasaurs.[4][3][5] It was closely related to Globidens, though is scantly known in comparison. The holotype specimen consists of an incomplete right dentary and most subsequently referred fossils are isolated teeth. The holotype dentary only preserves the posteriormost teeth, meaning that until recently when more comprehensive material was recovered, most of the dentition of the genus (its most distinctive feature) was unknown.[6]
Carinodens can easily be distinguished from the closely related Globidens by the compressed nature of its teeth and its relatively delicate dentary.[7]
Russell (1967) offered a brief diagnosis (due to the fragmentary nature of the fossils) of the genus, then known as Compressidens: "Small projection of dentary anterior to first dentary tooth. Median dentary teeth bilaterally compressed, bicarinate, subrectangular in lateral view and with pointed apices. Anterior teeth circular in cross-section with strongly recurved pointed apices".[7]
By mosasaur standards, the teeth of Carinodens are unusually heterodont, both in morphology and size. The alveoli show a marked size decrease between teeth #8 and #7, and the teeth themselves change dramatically in both size and morphology between #8 and #7. This is similar to the maxillary teeth of Globidens dakotensis (between positions #5 and #6, though this is less pronounced than in Carinodens) and in Globidens alabamaensis.[6]