a–d, Schematic drawings of skull and mandible. Skull in dorsal (a) and ventral (b) view, mandible in dorsal view (c), skull and mandible in right lateral view (d). e–g, Right lower teeth in labial view. h, i, Teeth of modern sperm whale Physeter (h) and killer whale Orcinus (i) for comparison. An, antorbital notch; As, alisphenoid; Ex, exoccipital; Fg, frontal groove; Fr, frontal; Iof, infraorbital foramen; La, lacrimal; Mc, mandibular condyle; Mf, mandibular foramen; Mg, mesorostral groove; Msb, margin supracranial basin; Mt, mesethmoid; Mx, maxilla; Or, orbit; Paf, palatine foramen; Pmf, premaxillary foramen; Pmx, premaxilla; Pty, posterior process tympanic; Rn, right bony naris; Sb, supracranial basin; Sq, squamosal; Tf, temporal fossa; Vo, vomer; Wf, wear facet; Zp, zygomatic process squamosal.