New species of extinct whale discovered in the Egyptian desert

2023-08-10 17:15:01

Recreation of the extinct basilosaurid whale Tutcetus rayanensis swimming in the Tethys Ocean of present-day Egypt, 41 million years ago. – HESHAM SALLAM – MANSOURA UNIVERSITY VERTEBRATE PAL

MADRID, 10 Ago. (EUROPA PRESS) –

A new species of extinct whale, ‘Tutcetus rayanensis’which inhabited the ancient sea that covered present-day Egypt some 41 million years ago, has been discovered by an international team.

Described in the magazine ‘Communications Biology’, this new whale is the smallest basilosaurid known to date and one of the oldest records of that family in Africa. Despite its diminutive size, Tutcetus has provided unprecedented data on the life history, phylogeny, and paleobiogeography of the earliest whales.

The Basilosauridae, a group of extinct fully aquatic whales, represent a crucial stage in the evolution of whales, in their transition from land to sea. They developed fish-like features, such as a streamlined body, a strong tail, fins, and a caudal fin, and had the last hind limbs visible enough to be recognized as “legs”, that they were not used for walking, but possibly for mating.

The newly discovered ‘Tutcetus rayanensis’ was found in mid-Eocene rocks and unambiguously helps to clarify the picture of early whale evolution in Africa. The name of the new whale is inspired by both Egyptian history and the place where the specimen was found.

The genus name, Tutcetus, combines “Tut” –in reference to the famous Egyptian pharaoh Tutankhamun– and “cetus”, Greek for whale, to highlight the small size of the specimen and its subadult status. The name also commemorates the discovery of the king’s tomb a century ago and coincides with the imminent opening of the Grand Egyptian Museum in Giza. The species name, rayanensis, refers to the protected area of ​​Wadi El-Rayan, in Fayoum, where the holotype was found.

Hesham Sallam, Professor of Vertebrate Paleontology at the American University in Cairo, founder of the Center for Vertebrate Paleontology at Mansoura University and director of the project, notes that “the evolution of whales from terrestrial animals to beautiful marine creatures embodies the wonderful adventurous journey of life”.

“Tutcetus is an extraordinary discovery that documents one of the early phases of the transition to a fully aquatic lifestyle that took place on that voyage”Add.

The holotype specimen consists of the skull, jaws, hyoid bone, and atlas vertebra of a small subadult basilosaurid whale that is embedded in a heavily compacted limestone block. With an estimated length of 2.5 meters and a body mass of approximately 187 kilograms, Tutcetus is the smallest basilosaurid known to date.

Lead author Mohammed Antar, from Mansoura University’s Center for Vertebrate Paleontology, and the National Focal Point for Natural Heritage explains that “Tutcetus significantly expands the size range of basilosaurid whales. and reveals considerable disparity among whales during the middle Eocene.”

“Investigation of the oldest layers of the Fayum strata may reveal the existence of an older set of early whale fossils, which could influence our current understanding of the appearance and dispersal of whales.”

Sanaa El-Sayed, a doctoral student at the University of Michigan (United States) and a member of the Sallam Laboratory, and a co-author of the study, points out that “the relatively small size of Tutcetus (188 kg) is a primitive retention or it could be related to the global warming event known as the “Late Lutecian Thermal Maximum (LLTM)”.

“This revolutionary discovery sheds light on the early evolution of whales and their transition to aquatic life.”

Thanks to detailed analysis of Tutcetus teeth and bones using computed tomography, the team has been able to reconstruct the pattern of growth and development of this species, providing an unprecedented understanding of the life history of the first whales.

The rapid dental development and small size of Tutcetus suggest a precocial lifestyle with a fast pace of life for early whales. In addition, the discovery of Tutcetus contributes to the understanding of the early success of basilosaurs in the aquatic environment, their ability to outcompete amphibian mother whales, and their ability to opportunistically adapt to new niches after their relationship with amphibians breaks. .

Abdullah Gohar, a PhD student at Mansoura University, a member of the Sallam lab and co-author of the study, notes that “modern whales migrate to warmer, shallower waters to breed and breed, reflecting conditions found in Egypt 41 million years ago.”

“This supports the idea that what is now known as the Fayum was a crucial breeding ground for ancient whales, possibly attracting them from various locations and, in turn, attracting larger predatory whales such as Basilosaurus.” .

The team’s findings have important paleobiogeographic implications, as they show that basilosaurs likely achieved rapid expansion throughout the southern hemisphere, reaching high latitudes in the middle of the Eocene.

Erik Seiffert, Professor and Professor of Integrative Anatomical Sciences at the University of Southern California and a co-author of the study, said: “The Eocene fossil beds of the western desert of Egypt have long been the most important in the world for understanding the early evolution of cetaceans and their transition to a fully aquatic existence”. Seiffert added: “The discovery of Tutcetus demonstrates that this region still has much to tell us about the fascinating history of whale evolution.”