Saghacetus is an extinct genus of basilosaurid early whale, fossils of which have been found in the Upper Eocene (middle Priabonian, 37.2 to 33.9 million years ago) Qasr el Sagha Formation, Egypt (29°42′N 30°48′E / 29.7°N 30.8°E / 29.7; 30.8, paleocoordinates 25°00′N 26°42′E / 25.0°N 26.7°E / 25.0; 26.7).

[2][3] In 1879, German botanist Georg August Schweinfurth spent many years exploring Africa and eventually discovered the first archaeocete whale in Egypt.

German palaeontologist Wilhelm Barnim Dames described the material,[4] including a well-preserved dentary which is the type specimen of Zeuglodon osiris.

This species is distinguished from other members of the subfamily Dorudontinae by its smaller size and the slightly elongated proximal lumbar and caudal vertebrae.

[7] Saghacetus was a small whale, reaching 4 m (13 ft) in length and 350–379 kg (772–836 lb) in body mass.