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Karenites
''Karenites'' is an extinct genus of therocephalian therapsid from the Late Permian of Russia. The only species is ''Karenites ornamentatus'', named in 1995. Several fossil specimens are known from the town of Kotelnich in Kirov Oblast.
==Description==
''Karenites'' is known from a partial holotype skeleton, two partial skulls, and isolated jaw bones. Although incomplete, the skulls preserve small and delicate structures like nasal turbinates on the inside of the skull and the stapes bone of the ear. The skull of ''Karenites'' is about long, with the snout much longer than the temporal region of the skull behind the eye sockets. Viewed from above, the skull is triangular. The snout is broad, and the skull widens toward the occiput or posterior margin. Two large holes behind the eye socket called temporal fenestrae occupy most of the posterior skull. Between these fenestra is a narrow sagittal crest. In front of this crest, the skull roof bones are weakly pitted with small bumps and ridges for blood vessels. Some specimens include parts of the sclerotic ring, a ring of bone embedded in the eye.〔
On each side of the upper jaw are five incisors, two or three precanines, one canine, and eleven or twelve postcanines. The incisors and precanines are long, thin, and slightly curved, separated from each other by a small gap. The canine is much longer, projecting slightly forward from the tooth socket and curving backward along its length. The postcanine teeth are shorter and broader than the incisors and precanines. Toward the back of the skull the tips of the teeth flatten. The lower jaw is thin and curves upward to the arch of the cheek, except for a large coronoid process that extends to the articular-quadrate jaw joint at the back of the skull. The lower jaw has three small incisors angled slightly forward, a large canine tooth projecting upward, and thirteen small, blunt postcanine teeth. The farthest postcanine teeth have small secondary cusps behind their tips. These multicusped teeth may have been adaptations for crushing food, although they are not as well developed as the teeth of other therocephalians like ''Ericiolacerta''.〔
In 1999, thoracic plates were reported to be present in the holotype of ''Karenites''. Thoracic plates are plates of bone on the underside of the rib cage that are typically found in reptiles, and unusual for mammal relatives like therocephalians. This bone was later reinterpreted as an interclavicle, part of the pectoral girdle common to all early therapsids.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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