On the vertex of the dorsal skull the premaxillary bone extends forward of the nasal and frontal bones. Separates from Berardius and Ziphius.

No sulcus exists in middle if the combined antero-dorsal surface of the nasals. Separates from Mesoplodon and Hyperoodon.

The area of the synvertex of the skull occupied by the nasal bones far exceeds that occupied by the frontals. Separates from Indopacetus.

There are between 17 to 27 pairs of rooted teeth in both the mandible and maxilla. Separates from Berardius, Hyperoodon, Indopacetus, and Mesoplodon.