Simply days after the world was launched to the heaviest identified historic whale, a a lot tinier member of the identical household has been discovered on the opposite facet of the planet.

The newly found species is one of many earliest — and smallest — basilosaurids, a household of historic aquatic creatures associated to trendy whales, researchers report August 10 in Communications Biology. It measured simply 2.5 meters lengthy, the group estimates, and weighed a mere 188 kilograms, about as a lot as a blue whale’s coronary heart.

“It’s positively a really small animal,” says Mark Uhen, a paleontologist at George Mason College in Fairfax, Va., who was not concerned within the research.

Researchers discovered the 41-million-year-old fossilized cranium, jaw and tooth of Tutcetus rayanensis in Wadi El-Rayan, a nature reserve in Egypt. Named partially after the Egyptian pharaoh Tutankhamun, the species shares King Tut’s regal roots: The title “basilosaurid” is derived from the Latin basilosaurus, or “king lizard” (the primary basilosaurid specimen was mistakenly categorised as a reptile).

Like Tutankhamun, the T. rayanensis specimen perished on the cusp of maturity. It nonetheless had a few its child tooth, together with grownup molars that grew in comparatively early in its life. That sample of tooth development means that the species “lived quick and died quick,” or no less than sooner than different basilosaurids, says research coauthor Abdullah Gohar, a paleontologist at Mansoura College in Egypt.

One other group of researchers just lately introduced the invention of the basilosaurid Perucetus colossus, probably the heaviest animal ever identified to exist, in Peru (SN: 8/2/23). Simply one in all its vertebrae weighed over half as a lot as its teeny cousin’s total physique.

T. rayanensis might have lived across the identical time as the large P. colossus, which rivaled trendy blue whales in physique mass, Gohar says. However their vastly completely different physique sorts point out that they in all probability occupied completely different ecological niches, Uhen says.

Gohar says he hopes to check older fossils to higher perceive the total story of whale evolution. The realm the place the researchers discovered T. rayanensis comprises 15 million years of mammalian evolutionary historical past, together with that of different early whales.

“We’ve been working that space for a very long time,” Uhen says. “It’s good to know that there are nonetheless issues on the market to find.”