|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Mammalia - Artiodactyla - Protocetidae
If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
|G. Bianucci and P. D. Gingerich 2011||Aegyptocetus tarfa differs from all protocetids except possibly Babiacetus indicus in having a cranium with a downwardly deflected frontal shield and rostrum of the skull (clinorhynchy; see below). Aegyptocetus differs in having a dentary with the mandibular condyle positioned well below the level of the lower cheek teeth, an ascending ramus deflected dorsally and medially to wrap around the braincase, and lower molars with the principle cusps angled backward (features related to cranial clinorhynchy). The protocetid Babiacetus has a cranium with a downwardly deflected frontal and rostrum, suggesting clinorhynchy like that documented here for Aegyptocetus, but deformation during burial means that clinorhynchy in Babiacetus cannot be quantified reliably. Aegyptocetus resembles Babiacetus in having a fused mandibular symphysis, but differs in having transversely broader upper posterior premolars (P3–4) and molars (M1–3). Upper premolars lack the well-developed posterobasal cusp present on P3 and the large metacone present on P4 in Babiacetus. There is no distinct protocone cusp on upper posterior premolars or molars of either Aegyptocetus or Babiacetus, but Aegyptocetus retains a prominent protocone lobe on the crowns of P3–M3, supported by a separate root. This lobe is medial, or slightly posterior of medial, relative to the paracone on P3–M3 of Aegyptocetus, whereas it is medial, or slightly posterior of medial relative to the posterior edge of the crown in Babiacetus. Cheek tooth occlusion in Aegyptocetus is more complex, like that of primitive protocetids, whereas cheek tooth occlusion in Babiacetus is simpler, more sectorial, and more derived.|