The newly discovered whale belongs to the Protocetidae, a group of extinct whales that falls in the middle of their transition from land to sea, the Egyptian-led team of researchers said in a statement.

Its fossil was unearthed from middle Eocene rocks in the Fayum Depression in Egypt's Western Desert — an area once covered by sea that has provided a rich seam of discoveries showing the evolution of whales — before being studied at Mansoura University Vertebrate Palaeontology Centre (MUVP).

The new whale, named Phiomicetus anubis, had an estimated body length of about 3 metres and a body mass of about 600kg, and was likely a top predator, the researchers said.

Its partial skeleton revealed it as the most primitive protocetid whale known from Africa.

The whale's genus name honours the Fayum Depression, and its species name refers to Anubis, the ancient Egyptian canine-headed god associated with mummification and the afterlife.

Despite recent fossil discoveries, the big picture of early whale evolution in Africa has largely remained a mystery, the researchers said.

Work in the region had the potential to reveal new details about the evolutionary transition of whales from being amphibious to fully aquatic.

With rocks covering about 12 million years, discoveries in the Fayum Depression "range from semi-aquatic crocodile-like whales to giant fully aquatic whales", said Mohamed Sameh of the Egyptian Environmental Affairs Agency, a co-author.

The new whale has raised questions about ancient ecosystems and pointed research towards questions such as the origin and coexistence of ancient whales in Egypt, said Hesham Sellam, founder of the MUVP and another co-author.

Key points:

• The fossil was unearthed from middle Eocene rocks in the Fayum Depression in Egypt's Western Desert
• The new whale was about 3m long and weighed about about 600kg
• It has been named Phiomicetus anubis, after the Egyptian god of death