Egyptian scientists have identified the fossil of a four-legged prehistoric whale, unearthed over a decade ago in the country's Western Desert.
The creature, an ancestor of the modern-day whale, is believed to have lived 43 million years ago.
It isn't the first fossil of a walking whale to be discovered, but it is believed to be one of the oldest from the Fayum depression area.
Living both on land and sea, it had a semi-aquatic lifestyle.
According to the team's leading palaeontologist, it had features of an accomplished hunter.
"This is the first time in the history of Egyptian vertebrate palaeontology to have an Egyptian team leading a documentation of a new genus and species of four-legged whale that lived here in Egypt 43 million years ago," says Hesham Sallam, Professor of palaeontology at Mansoura University and American University in Cairo.
The fossil was first found by a team of Egyptian environmentalists in 2008 in an area that was covered by seas in prehistoric times, but researchers only published their findings that it is a confirmed new species last month.
Sallam's team did not start examining the fossil until 2017 because he was keen on first finding a talented Egyptian palaeontologist to lead the investigation.
The fossil sheds light on the evolution of whales from herbivore land mammals into carnivorous species that today lives exclusively in water.
"We named it 'Phiomicetus anubis' (discovered whale) and 'Phioum' in honour of Fayum depression. 'Cetus' means in Latin 'whale' and 'Anubis' is the god of death in Pharaoh time. So, it's a very important discovery because it documented one of the missing link or transitional form in the history of (the) whale from living totally on land as a terrestrial animal to a fully aquatic whale that is living today," says Sallam.
The transition took place over roughly 10 million years, according to an article published in the journal Proceedings of the Royal Society B.
Egypt's Western Desert region is already known for the so-called Whale Valley, or Wadi Al-Hitan, a tourist attraction and the country's only natural World Heritage site that contains fossil remains of another type of prehistoric whales
The newly-discovered creature belongs to the family of Protecetids, extinct semi-aquatic whales that lived 59 to 34 million years ago, Sallam says.
It would have walked on land but also hunted in the water.
"Its length was approximately three meters and it weighed approximately 600 kilograms. Therefore, it is one of the largest and most ferocious predators in the region where it lived 43 million years ago," says Abdalla Gohar, a researcher at Mansoura University Palaeontology Centre.
The oldest fossil whales are about 50 million years old and are believed to have originated in modern-day Pakistan and India.
However, scientists have not been able to reach a conclusive answer as to when whales moved out of their point of origin to all the world's oceans.
The new find could possibly serve as a link between Indo-Pakistan and North American regions.
"(The) 'Phiomicetus anubis' whale is an important whale because it is amphibious with four limbs, and its importance came from being located in half of the evolutionary chain of whales," says Gohar.
The new species stands out for its elongated skull and snout which suggests it was an efficient carnivore capable of grasping and chewing its prey.
It is also believed to have had sharp hearing and smelling senses.
The discovery followed a four-year collaboration between Egyptian palaeontologists and U.S-based scientists.
Sallam's team has previously made headlines worldwide with their 2018 discovery of Mansourasaurus, a new species of long-necked herbivorous dinosaurs that lived in the Nile Delta province of Mansoura.