Domningia, Thewissen & Bajpai, 2009

Thewissen, J. G. M. & Bajpai, Sunil, 2009, A new Miocene sirenian from Kutch, India, Acta Palaeontologica Polonica 54 (1), pp. 7-13 : 7-8

Genus Domningia nov.

Type species: Domningia sodhae sp. nov.

Etymology: Named for Dr. Daryl Domning, who has contributed greatly to the understanding of sirenian evolution.

Included species.— Type species only.

Diagnosis.—Dugongine with upper incisors which are greatly flattened medio−laterally, and multi−rooted upper premolars, unlike most dugongines. Domningia differs from Corystosiren and Rytiodus in having incisors that are more or less flat (not oval) on cross−section and in having a long nasal process of the premaxilla. In Domningia , the exoccipitals meet in the median plane dorsal to the foramen magnum, unlike Dioplotherium and Bharatisiren .

Stratigraphic and geographic range.—Aquitanian (lower Miocene) of Kutch, India.

Discussion.—Dugongines were defined by Domning (1994) on the basis of three unique characters. The most important ones of these that can be discerned in Domningia concerns the shape of the postorbital process (character 43 of Domning 1994). The non−circular cross−section of the upper incisor further identifies the new genus as closely related to a cluster of genera similar to Rytiodus , previously referred to as the subfamily rytiodontines (this grouping is denied official status by Domning, 1994, but the name is still sometimes used informally). Genera with greatly medio−laterally compressed incisors include Corystosiren , Rytiodus , and Dioplotherium . Domningia differs from Corystosiren and Rytiodus in having more−or−less flat (not oval) upper incisors (character 141 of Doming 1994) and in having a long nasal process of the premaxilla (character 7). In both these features Domningia is more plesiomorphic than Rytiodus and Corystosiren , resembling the more basal Dioplotherium . Domningia differs from Dioplotherium in having the exoccipitals meet in the median plane dorsal to the foramen magnum (character 66 of Domning 1994).

Bharatisiren is a dugongine ( Bajpai and Domning 1997; Bajpai et al. 2006) similar in many respects to Domningia . Both have multi−rooted premolars, for instance, a feature also found in Dioplotherium manigaulti . It is possible that these are deciduous premolars, as is the case in many post− Eocene sirenians. Both Bharatisiren and Domningia have a long nasal process of the premaxilla. We conclude that Domningia is a basal dugongine and part of a group of clades mainly charactized by their flattened upper incisors.