It’s been a record-smashing month for ancient whales. Last week, scientists unveiled fossils of what could have been the heftiest animal to ever live, a prehistoric whale that clocked in at 400,000 pounds. And now, paleontologists have announced a groundbreaking find on the other end of the spectrum: a tiny, extinct whale that weighed only 410 pounds. The little creature grew just about eight feet long—or the size of a modern-day bottlenose dolphin.
“These findings together exemplify the remarkable diversity that characterized the Eocene marine ecosystems,” study author and paleontologist Hesham Sallam, a paleontologist at Mansoura University and the American University in Cairo, tells Gizmodo’s Isaac Schultz.
How did we end up with THE LARGEST known Basilosaurid (Perucetus) and THE SMALLEST known Basilosaurid (Tutcetus) at exactly the end and start of one week???— Riamus (@Riamus01) August 10, 2023
Man it's been the week of the king whales lately. pic.twitter.com/OslNnptwMR
The miniature species is the smallest known whale from an extinct family called basilosaurids, according to the new research, published Thursday in the journal Communications Biology. Long ago, whale ancestors walked on four legs along beaches—and the basilosaurids are the earliest known group to have left the land for good, swimming into the sea to become the first family of fully aquatic whales.
Now, some 41 million years later, Egyptian researchers found the limestone-encased partial skeleton of one of these diminutive mammals. The team uncovered the fossil 25 miles from the Wadi Al-Hitan World Heritage Site in Egypt, an area rich with whale specimens.
The discovery “helps clarify parts of the evolutionary tree and pushes back some of the changes we thought were happening,” paleobiologist Nicholas Pyenson, a fossil curator at the Smithsonian’s National Museum of Natural History who wasn’t involved with the research, tells CNN’s Jenna Schnuer.
The team christened the new species Tutcetus rayanensis—Tutcetus pays homage to the Egyptian pharaoh Tutankhamun, whereas rayanensis references the Wadi El-Rayan locale where scientists dug up the fossil.
The fossil itself is an incomplete skull with jaws, teeth and the topmost spinal vertebra. Notably, the teeth have smooth enamel, which suggests T. rayanensis survived on squishy foods such as octopus and squid, Jennifer Nalewicki writes for Live Science. Based on the fusion patterns of the skull bones and developmental stages of the teeth, the researchers posit that the whale was a sexually mature adolescent when it died.
Overall, the species probably “lived fast and died fast” compared to its relatives, Abdullah Gohar, a study author and paleontologist at Mansoura University in Egypt, tells Live Science. The mini-whale’s rapid life cycle is reminiscent of the short life of King Tut, its namesake. The famous pharaoh died when he was 18 years old.
T. rayanensis’ short lifespan and diminutive constitution could have been adaptations to a warming climate. The specimen’s age roughly coincides with a period of global warming called the Late Lutetian Thermal Maximum, which occurred some 42 million years ago. During that time, basilosaurids the world over probably came in petite sizes compared to their descendants that enjoyed cooler conditions, write the authors in the study.
A paper in @CommsBio describes the fossilised remains of a new species of basilosaurid—an extinct family of fully aquatic whales. The whale is thought to be the smallest known basilosaurid and has been named Tutcetus rayanensis. https://t.co/qDXX0J6TjT pic.twitter.com/ecalg0x4e9— Nature Portfolio (@NaturePortfolio) August 10, 2023
Beyond revealing another record-breaking find, the new study is also a victory for Egyptian and African paleontology, CNN reports. After all, it was Egyptian scientists who led the international team that discovered and examined the specimen—and named it after an Egyptian icon.
“I think the most important thing [is] really how special it is that we have Egyptian-led science coming out of Egypt on Egyptian fossils,” Miami University paleobiologist Carlos Mauricio Peredo, who wasn’t involved in the study, tells CNN. “That has historically not been the case.”