What is a new kind of mammal 'crazy beast' that lived 70 million years ago like the dinosaur?

In 1999, a research paper was announced that the fossil discovered in the formation of

Madagascar island in almost perfect condition belongs to a new genus and new species of mammal that inhabited the Gondwana continent existing in the southern hemisphere of the ancient earth. . A research team led by Denver's Museum of Natural Sciences, David Klaus, named the mammal ' Adalatherium hui, ' which means 'crazy beast.'

Skeleton of a Cretaceous mammal from Madagascar reflects long-term insularity | Nature

Fossil of 'crazy beast' skeleton uncovered-Scimex

Strange 'Crazy Beast' Skeleton May Be Oldest Mammal Unearthed in Southern Hemisphere

The fossils of Adalatherium hui were excavated in 1999 from a stratum from about 721.1 million to 66 million years ago called ' Maastrichtian ' in the late Cretaceous , and it is said that they lived in the Gondwana continent. It is considered to be a mammal belonging to the subterranean order. It is the oldest fossil mammal species excavated in the Southern Hemisphere.

Fossils of mammals belonging to the subgenus Gondwanaterium have been excavated, but only fossils of jaws, teeth, and skulls have been found in pieces, and the suborders of Gondwana theterium are anatomical and paleontological. Little was known about what kind of creature was scientifically and phylogenetically. The fossils discovered this time were of an immature individual, but they kept almost the whole body, and small bones and cartilage tissues were also preserved.

The fossil from which the following image was excavated. The head, front legs, hind legs, spine, ribs and almost all of the bones of the whole body are arranged.

One of the authors of the paper, Associate Professor Alistair Evans, who studies phylogenetic chemistry at Monash University, said that the results of the study on fossils excavated in 1999 were finally reported in 2020. It took me about 20 years to study and show what kind of mammal it was and how it lived. '

According to Associate Professor Evans, a huge amount of work was required to restore fossils. It seems that it took work to combine more than 100 pieces to repair one tooth of Adalatherium hui. You can see the CG model of the teeth of Adalatherium hui in the following movie released by Associate Professor Evans.

Fragmented Adalatherium tooth being reconstructed-YouTube

The image of Adalatherium hui based on fossils of the whole body is shown below. Adalatherium hui has short legs and tail and a sturdy skeleton, but is believed to have been unable to swim. The estimated weight is 3.1 kg, and it seems to be about the size of a cat, but it is said to be the largest size among mammals that inhabited the Gondwana continent. The scientific name Adalatherium hui seems to be given from the Madagascar word meaning 'madness' and the Greek word meaning 'beast'.

Adalatherium hui is said to be a closely related species of the “Toka Teeth ” that has inhabited a lot in the Jurassic to Cretaceous, but was extinct about 35 million years ago, but the research team says that the fossil of Adalatherium hui is Madagascar island. It is said that it has a great meaning to be discovered in.

Madagascar Island, located in southeastern Africa, was separated from Gondwana continent and became an island 90 million years ago due to the effects of continental migration . Therefore, it is considered that Madagascar Island has developed its own unique ecosystem that is different from the continent.

by Hannes Grobe / AWI

For example, the primitive intramembranous bone in the skull of Adalatherium hui is a bone lost in the process of evolution about 100 million years ago and is not found in many existing mammals. The skull also has more openings than known mammals, which may have been pathways for nerves and blood vessels to increase sensitivity of the nose and mustache, the team said.

The research team commented, `` In Madagascar, in addition to limited resources, competition between species was reduced compared to the Gondwana continent, there were fewer predators and parasites, so it is thought that a unique evolutionary system was established. '' I will.

Little is known about how the Adalatherium hui evolved and became extinct, but there are many unknowns about the ecosystem of the Gondwana continent, so almost complete Adalatherium hui fossils are a great discovery. I will. 'The Adalatherium hui is an important piece of a big puzzle in the early stages of mammalian evolution in the Southern Hemisphere, but few other pieces are yet in place,' said Evans.

in Science,   Creature, Posted by log1i_yk