Allotheria

(paleontology) A subclass of Mammalia that appeared in the Upper Jurassic and became extinct in the Cenozoic.

One of the four subclasses of Mammalia, containing a single order, the Multituberculata. The Allotheria first appeared in the Late Jurassic and survived well into the Cenozoic, a period of at least 100,000,000 years. Fossils are known from North America, Europe, and Asia.

The diagnostic features of the subclass are in the dentition. There is a pair of enlarged incisors above and below; reduced lateral incisors may persist in the upper jaw. Canines are absent, leaving a diastema between incisors and cheek teeth. Premolars are variable and often reduced. The lower molars have five or more cusps in two parallel longitudinal rows, and the upper molars have two or three parallel rows of cusps; hence the molars are multituberculate. See also Dentition; Mammalia; Multituberculata.