In the United States, paleontologists have found the skull of an ancient Cretaceous mammal. The find suggests that the Pangea supercontinent split millions of years later than it was believed - otherwise these animals would not have been able to penetrate the territory of America.
In 2006, a group of paleontologists from the University of Southern California in the United States, in eastern Utah, studied the fossilized remains of a dinosaur and came across a small skull of an unknown animal. Now, having studied it, scientists have established: this is the skull of an ancient herbivorous mammal of the Haramiid order, the age of the find was 130 million years. The new species was named Cifelliodon wahkarmoosuch, after the famous American paleontologist Richard Sifelli. The word wahkarmoosuch from the language of the Utah Indians is translated as "yellow cat".
Earlier, the remains of the Haramiids were found in Europe, Asia, Greenland and belonged to the Triassic period - it preceded the Jurassic, when the supercontinent Pangea was believed to split in two.
However, the new find belongs to the Cretaceous period, which followed the Jurassic - and, therefore, by the time the yellow cats migrated from Asia to Europe, and then to North America and the southern continents, Pangea was still intact.
Probably, its split occurred about 15 million years later than previously thought. The researchers spoke about the discovery in an article in the journal Nature.
The first remains of the haramids - teeth and jaws - were found in the 1990s in Eurasia and belonged to the Jurassic and Triassic periods. In 2014-2015, animal skeletons were found in China, which sparked a debate about where the haramiids should be on the evolutionary tree.
If we consider them mammals, then mammals appeared about 220 million years ago. If not, other finds point to the appearance of mammals about 185 million years ago. At the moment, it was decided not to exclude haramids from mammals.
“Based on the unexpected discovery of this virtually complete fossilized skull, we now recognize the existence of a new, widespread group of early mammals,” notes Adam Hattenlocker, lead author of the study.
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Scientists were struck by the safety of the skull.
“Basically, the remains of the ancient relatives of mammals are represented by teeth. The find is unique in that it is one of the virtually intact Lower Cretaceous mammalian skulls in North America and the only mammalian remains of this period in Utah,”Hattenlocker said.
Adam Huttenlocker / University of Southern California.
The authors of the work studied the skull using computed tomography. According to their calculations, the body weight of the animal was only about 1.1 kg, but among other mammals of those years, the animal was a giant.
“It looked like a giant compared to the Mesozoic proto-mammals,” says paleontologist and study co-author James Kirkland, who first stumbled upon the skull. "He was like Godzilla among them."
The animal had large olfactory bulbs and small eyes, indicating a strong sense of smell and poor vision. Most likely, the animal was nocturnal and found food primarily by smell. The shape of his only surviving tooth turned out to be similar to the shape of the teeth of herbivorous fruit-eating bats - probably, the diet of the "yellow cat" was similar.
Researchers are highlighting the importance of this single tooth.
“This tooth now allows the haramids to expand their habitat to the whole continent - North America. And they lived there much later than previously thought,”notes paleontologist David Krause.
“The skull of a sifelliodon is an extremely rare find on the territory of the Western Inland Sea (an ancient sea that existed from the middle to the end of the Cretaceous period in the territory of modern Canada and the United States. -“Gazeta. Ru”), where the remains of mammals and their reptile-like ancestors are mainly represented by individual teeth and jaws,”emphasizes Kirkland.
In addition, the find changes the understanding of mammalian evolution, scientists say.
“For a long time, we thought that early Cretaceous mammals were anatomically similar and not ecologically diverse,” Hattenlocker explains. - The discovery of our team, and other researchers, shows that even before the appearance of modern mammals, their ancient relatives occupied special niches - among them were insectivores, herbivores, carnivores, and aquatic animals. They occupied the same niches as modern mammals."
The researchers note that the skull of the "yellow cat" is not the only find that indicates a later division of Pangea. This is also indicated by a number of fossils found in Africa and Europe. So the question of establishing the exact time period when Pangea split is still open.
Alla Salkova