Ziphius, Cuvier, 1823

Bianucci, Giovanni, Lambert, Olivier & Post, Klaas, 2007, A high diversity in fossil beaked whales (Mammalia, Odontoceti, Ziphiidae) recovered by trawling from the sea floor off South Africa, Geodiversitas 29 (4), pp. 561-618 : 576-577

Ziphius sp.

REFERRED SPECIMEN. — SAM PQ 2826, a fragment of cranium including most of the vertex, the right and part of the left premaxillary sac fossae.

LOCALITY. — Trawled at 35°11’S, 23°26’E, south coast of South Africa, Indian Ocean, depth of 1000 m.

DESCRIPTION AND DISCUSSION

( FIG. 12 ; TABLE 3)

The anterior surface of the ascending process of the premaxilla is distinctly concave up to its dorsal portion, overhanging the premaxillary sac fossa. The highly asymmetric premaxillary crests (the right crest two times wider than the left) are anterolaterally directed. The nasals are greatly elongated anteriorly, being almost twice longer than wide. Their median suture is anteriorly shifted to the left.

SAM PQ 2826 only differs from the Recent Ziphius cavirostris in: its larger size (see comparison of measurements with the largest skull of Z. cavirostris from the SAM collection, Table 3), the longer contact between nasal and premaxillary crest (a condition intermediary between Z. cavirostris and the Pliocene Tusciziphius crispus ), and the relatively smaller nasals.

Considering the strong similarities with Z. cavirostris at the level of the vertex, this specimen should be referred to the same genus. Because of its clearly larger size it may represent a new species of Ziphius , but in view of its fragmentary preservation diagnosis at specific level is not currently possible.

Figures

FIG. 12. — Skull fragment of Ziphius sp. (SAM PQ 2826): A, dorsal view; B, corresponding line drawing; C, lateral view; D, anterior view; E, corresponding line drawing. Scale bars: A, B, 5 cm; C-E, 10 cm.