Globidens ("Globe teeth") is an extinct genus of mosasaurid oceanic lizard classified as part of the Globidensini tribe in the Mosasaurinae subfamily.
Globidens alabamaensis was the first species of Globidens described, in a publication by Charles W. Gilmore (1912). It is used as the type specimen for Globidens.
Globidens belongs to the family Mosasauridae, which consists of several genera of predatory marine lizards of various sizes that were prevalent during the Late Cretaceous. Specimens of Globidens have been discovered in Angola, Brazil, Morocco, Syria and the United States.[1] Among mosasaurs, Globidens is probably most well known for the highly rounded, globe-like teeth that give it its name.
Globidens was a relatively medium-sized mosasaur, measuring about 5–6 metres (16–20 ft) long.[2] It was similar in appearance to other mosasaurs, with its streamlined body, flippers, a laterally flattened tail, and powerful jaws. The teeth of Globidens differed from those of other mosasaurs in being rounded or “globular”, giving rise to its generic name. Most mosasaurs had sharp teeth evolved to grab soft, slippery prey like fish, squid, plesiosaurs, and other mosasaurs. In some later mosasaur species, their teeth were modified to rend flesh as well. While many other mosasaurs were capable of crushing the shells of ammonites or turtles, none were as specialized for dealing with armored prey as Globidens. Globidens had semispherical teeth with rounded points suited for crushing tough, armored prey, including turtles, ammonites, nautili, and bivalves. Like its larger relative, Mosasaurus, Globidens had a robustly built skull with tightly-articulating jaws and a strong bite that played a large role in the animal’s ability to penetrate the armor of its shelled prey.
Gilmore's initial assessment of Globidens, based on an incomplete specimen of G. alabamaensis, made note of characteristics observable in parts of the skull, the teeth, and one of the cervical vertebrae. He made note of a long snout with a large maxilla, a large, sturdy frontal bone, and the characteristic globular teeth with finely wrinkled enamel. Gilmore concluded that the skull characters were similar to Platecarpus or, more closely, to Brachysaurus (which is currently Prognathodon).
Studies since Gilmore's assessment establish more specific and more complete lists of diagnostic features. Gilmore correctly inferred that Globidens had a stout, powerfully built skull. In addition, a few of its notable skull characteristics include a small parietal foramen located entirely within the parietal, tuberosities present on the jugal, a longitudinal crest present on the dorsal surface of the frontal, and a premaxilla with a rostrum anterior to the premaxillary teeth.[3] The rounded teeth with finely wrinkled enamel seen in Globidens are characteristic of Globidensini. However, the degree of rounding on individual teeth may be indicative of genus or even species. Marginal teeth in Globidens become most subspherical toward the center of the jaws. Additionally, Globidens had thirteen maxillary teeth and either lacked or showed only rudimentary pterygoid teeth on the roof of its mouth.[3]