Relationships of the Hooded and Elephant seals (genera Cystophora and Mirounga )

The characters linking Mirounga and Cystophora in the subfamily Cystophorinae are the reduction of the incisors to 3 / 1 , the nasal sac of the male, and also the general similarity in shape of the postcanine teeth. Because of the unreliability of dental characters, and the possibility of convergence producing the nasal sac, the entire skeleton and some soft parts of the body have been considered. This examination has produced 17 good characters in which Cystophora agrees with other northern phocids, and Mirounga with other southern phocids. Other characters confirming this division, but not considered trenchant enough for inclusion in the table, have also been found. It is suggested that the subfamily name Cystophorinae be abandoned. The family Phocidae is therefore divisible into two subfamilies; Cystophora being included in the Phocinae, and Mirounga in the Monachinae. Certain characters suggest that Erignathus and Monachus may be the forms linking the typically northern and the typically southern phocids.