The title reports the recent discovery and describes it as a strange mixture of reptiles and mammals. However, although it may be interesting to imagine a wild animal in front of a lizard and behind a mouse, it is not very scientific. [Really? 8 exotic hybrid animals]
This small animal was only 3 inches (7.6 cm) tall and weighed about 2.5 pounds (1. 1 kg). It belongs to a group called Harami Yidan people, which appeared in the late Triassic (from 25 1 100 million years ago to199 million years ago), mainly because scientists debated whether Harami Yidan people were early mammals or sister groups closely related to mammals, but they lacked some characteristics of paleontologists to judge who was a mammal and who was not.
In a new study, this little skull is described as-it represents a new genus and species of Harami Yidan, called Cifelliodon wahkarmosuch. Researchers have determined that the Harami Yidan people are relatives of mammals, although they are not real mammals. Scientists report that although the Yidan people in Harami look like mammals, they retain more "non-mammal" structures from their distant ancestors than the first real mammals. 25 magical ancient beasts
Harami Yidan and mammals can be traced back to a group called synapsids. Elsa Panciroli, a paleontologist who was not involved in the new study, told Life Science in an email.
In other words, mammals have no "reptile ancestors". On the contrary, Panciroli explained that the ancestors of mammals and reptiles all branched from a common ancestor hundreds of millions of years ago.
In the past, scientists might say that early synapses and reptiles had more common features than mammals. Pan Kiloli, a doctoral student studying the origin of mammals at the University of Edinburgh and the National Museum of Scotland, said, "But we really need to see it as about which group is more like their common ancestor. One feature found in reptiles and preserved in some modern mammals is oviposition, which is found in platypus and spiny anteater. Oviposition can be traced back to the ancestors of reptiles and mammals very far away. On the other hand, mammals with placenta are thought to have originated from an animal similar to a shrew that lived 654.38+600 million years ago.
It is a transitional skull, and the newly described Sivoridon must be similar to mammals. It has a hairy body and a long tail. Its teeth can cut and crush plants. The small eye socket means that its eyes are small and its eyesight is poor. However, according to research, its olfactory bulb is unusually large, which shows that it is very dependent on the sense of smell. The researchers wrote:
High-resolution X-ray scanning also shows the shape of the internal skull, which is "the transition between early dry mammals and crested mammals". This means that the Xifei ivory elephant and other Harami Yidan people have some characteristics similar to mammals, but not as many as the groups that define mammals today.
The special situation of Xifei ivory elephant skull, especially its three-dimensional shape, provides clues to Harami Yidan Group, which was only speculation before. When the only fossil is scarce or crushed, lead author Adam Hartenlock, assistant professor of clinical integration, told USC News.
"The three-dimensional preservation of Cifelliodon highlights the primitive brain, taste and diet structure of this special group, and strengthens their position near the basis of mammalian genealogy," Huttenlocker said.
This discovery was published in the online edition of Nature on May 23rd.
Editor's Note: This article was updated on June 8th, adding some information to clarify the ancestral relationship between mammals and reptiles.
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