February 20, 2024

Discovered ‘killer dolphin’ 25 million years ago in study | Sciences

By observing the collection of fossils at the University of Otago’s Geology Museum in New Zealand, a team of researchers has been able to describe a new species of predator, the ancestor of modern dolphins. nominate them Nihohae MatakoeiIt would have lived about 25 million years ago, and one of its main features was its long and sharp teeth, which protruded from its nostrils.

Scientists, led by Professor Amber Coast, have studied a well-preserved complete specimen of the animal’s skull, which was originally discovered on a cliff on New Zealand’s South Island in 1998. The findings are described in a publication in the journal Proceedings of the Royal Society b.

The skull is about 60 cm long, and features teeth in two different shapes. In the part of the jaw closest to the face they are regular and vertical; Near the muzzle, it is long and flat, ranging in size from 8 to 11 cm.

Close examinations showed very little wear on the front teeth, indicating that the species did not scavenge sand for food. Likewise, the flat teeth, because they did not fit together, reveal that the mouth was not the best means of catching fish.

Illustration of a Nihohae matakoi chasing a squid in the ocean during the Oligocene (34 to 23 million years ago) – Photo: Reproduction/Daniel Verhelst via Live Science

The findings raised more questions for the researchers about how these animals were fed. It was then that the team began to consider that these ancient “dolphins” could have the same behavior as modern sawfish.

“Sawfish are rays with a snout that looks like long, flat saws. To eat, they pounce among the prey, hitting them with their teeth in a back-and-forth motion. This injures and stuns the victim, which is easier to swallow, ”explains Kost, in an interview with Al-Gate. Science lives.

This potential similarity in hunting technique is supported by analysis of the cervical vertebrae n. mataqui. Unlike modern dolphins, whose neck bones are fused, their ancestors had a skeletal organization that favored a greater range of motion, which aided them in attacks.

Based on their findings, the team believes that these animals did not eat fish with hard bones or scales, preferring a diet of squid and octopus, which have softer bodies. It is also possible that, in addition to feeding, the teeth had some sexual or social functions, although this is difficult to prove.

The use of these prominent teeth should be investigated further in future research. There are still questions to be answered in order to understand why these tools continued to appear in other groups of animals, but changed in the evolution of dolphins.