A strange “cunning beast” that lived among dinosaurs magic scientists

Adalatherium fossils

Adalatherium fossils. Reputation: Simone Hoffmann and Kathrine Pan

The strange features of this mum have led scientists to believe how it could have evolved; “He stoops and even breaks a lot of rules.”

Adalatherium is an important piece in a very large puzzle of mammalian early evolution in the southern hemisphere, one in which most of the other pieces are still missing.

New research published today in the Journal of Vertebrate Paleontology describes a 66 million year old strange mammal that takes new insights into the evolutionary history of mammals from southern Gondwana – now known as Africa, South America, Australia, Antarctica, sub-region of India, and Arabian peninsula.

Named Adalatherium, which, translated from the Malagasy and Greek languages ​​means “cunning animal,” is defined based on an almost complete, preserved skeleton, the most complete for any mammal yet found in the southern hemisphere before the dinosaurs became extinct.

The research, conducted over 20 years, shows that Adalatherium it was a “giant” compared to the shrew-sized mammals or mice that lived during the period Cretaceous time.

Picture of Adalatherium

A life-like reconstruction of Adalatherium hui from the Cretaceous Late of Madagascar. Credit: © Denver Museum of Nature & Science / Andrey Atuchin

Its “weird” features include more vertebra trunk than most other mammals, muscle end organs placed in a more sprawling position (similar to modern crocodiles) along with braided front legs that have been carved under the body (as seen in most mammals today), rabbit-like front teeth and back teeth completely unlike any other known mammalian tooth, alive or extinct, and a strange gap in the bones at the tip of the nose.

A team of 14 international researchers led by Dr. David Krause (Denver Museum of Nature & Science) and Dr. Simone Hoffmann (New York Institute of Technology) published the description and extensive study of mammalian opossum size this who lived among dinosaurs and mostly crocodiles near the end of the Cretaceous period (145¬-66 million years ago) on Madagascar.

The 234-page monograph treatment, consisting of seven separate chapters, is part of the prestigious Vertebrate Paleontology Society (SVP) Memorial Series, a special annual publication that provides in-depth treatment of the most important vertebra fossils. The first news of the discovery was made in the journal Nature earlier this year.

Adalatherium, from Madagascar, belongs to a group of extinct mammals called gondwanatherians, first discovered in the 1980s and, until recently, represented by only a few isolated teeth and jaw fragments. But even these remnants already showed that gondwanatherians were quite different from other contemporary mammals. There were so many mysteries surrounding gondwanatherians that it was not clear how they would weave into the mammal family tree.

Now the research team is unveiling the first skeleton for this mysterious group that once roamed much of South America, Africa, Madagascar, the Indian subcontinent, and even Antarctica.

Excellent skeletal integrity and preservation of the Adalatherium opening new windows into the appearance of gondwanatherians and how they lived, but the weird features are still with the anxious team.

“Getting to know what we know about the skeletal anatomy of all living and extinct mammals makes it hard to imagine that a mammal is similar. Adalatherium could come forward; it bends and even breaks a lot of rules, ”Krause explains.

Although reconstruction is like life Adalatherium Much like a run-to-mill badger, its “normality” is only deep in skin. Beneath the surface, its skeleton is scarce of rural land.

As Hoffmann said, “Adalatherium simply. It was challenging to find out how he moved, for example, because his front end tells us a completely different story than the back end. ”

Although the muscular hind legs and large claws on the hind legs may indicate that Adalatherium he was a powerful digger (like badgers), his front legs were less brauny and they are more like the feet of live mammals that can run fast.

The members of Adalatherium also shows that the postal situation was different between those of living mammals and old relatives. Her forelimbs were slit under the body (as seen in most mammals today) but the hind arms were more sprawling (as in jars and berries).

These are not the weird stops.

Teeth are the Adalatherium, reconstructed using high-resolution microcomputer tomography and extensive digital modeling, as a hallmark of botany but are otherwise beyond bizarre.

Not only did he Adalatherium growing front teeth resemble rabbit or rodent, but the posterior teeth are completely unlike any other known, living or extinct mammal teeth. If only these teeth had been found, the mystery of what this beast had discovered would probably not have been solved! Added to the apparent turbulence is a hole in the top of the nose where it is not directly parallel.

About the size of an opossum in Virginia, the 3.1 kg Adalatherium very big for his day. Although not particularly large by modern standards, it was a giant compared to the mouse and mouse-sized mammals that inhabited the Cretaceous.

The geological history of Gondwana gives an idea of ​​why Adalatherium so weird.

Adalatherium it was found in rocks with a date near the end of the Cretaceous, about 66 million years ago. By this time Madagascar had already been an island separated from Africa for over 150 million years and from the Indian subcontinent for over 20 million years. “Islands are a weird thing,” says Krause, “so there was plenty of time Adalatherium to develop its own unique features on its own. “

Adalatherium is an important piece in a very large puzzle on the early evolution of mammals in the southern hemisphere, one in which most of the other pieces are still missing, ”said Hoffmann.

More than anything, find out Adalatherium showing more to be learned from a new discovery of early mammals in Madagascar and other parts of the southern hemisphere.

Information: “Introduction to Adalatherium hui (Gondwanatheria, Mammalia) from Cretaceous Late of Madagascar ”with David W. Krause, Joseph R. Groenke, Simone Hoffmann, Raymond R. Rogers and Lydia J. Rahantarisoa, 18 December 2020, Journal of Vertebrate Paleontology.
DOI: 10.1080 / 02724634.2020.1805455