- Adalatherium is an important part of a very large puzzle on the early evolution of mammals in the southern hemisphere, one in which most of the other parts 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 deep 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 he was a “giant” compared to the shrew-size mammals or mice that lived in Cretaceous times.
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 brawny explosive front legs trapped under the body (as seen in most mammals today), rabbit-like front teeth and back teeth completely unlike any other known mammalian teeth , alive or extinct, and a strange gap in the bones at the top of the nose.
The description and extensive study of the mammal was published by 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). the size of this opossum that lived among dinosaurs and giant 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 remains 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 fit 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.
“Knowing what we know about the skeletal anatomy of all living and extinct mammals, it’s hard to imagine that a mammal is like Adalatherium could come forward; he bends and even breaks a lot of rules, “Krause explains.
Although reconstruction is like life Adalatherium remarkably similar to a run-to-mill badger, its “regularity” is only deep skin. Beneath the surface, its skeleton is scarce of rural land.
As Hoffmann puts it, “Adalatherium simply. Trying to figure out how he moved, for example, was challenging 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 animal had discovered would probably not have been solved! Added to the seeming disturbance is a hole in the top of the nose where it is not directly parallel to it.
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 for them Adalatherium to develop its own unique features on its own. “
“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, “says 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.
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The Vertebrate Society’s Memoir Paleontology series represents one of the few print publishing platforms for monographic manipulation such as those completed for Adalatherium with Krause and Hoffmann. Of particular note is this work using a comprehensive approach to digital modeling (μCT), with the data accessible to researchers through Morphosource; Phylogenetic information used in the complete study is available through Morphobank. Funding to support site and laboratory research was provided by the National Science Foundation and the National Geographic Society.
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