165-million-year-old fossil from China reveals mammal ancestor that swam and swallowed like mammals

An X-ray photograph of the Megacauda fossil Scientists have examined a 165-million-year-old fossil found in China and identified a mammal predecessor that had a broad tail for swimming and throat bones similar to those found in modern mammals. The discovery suggests that some early relatives of mammals had already developed ways of chewing and swallowing food millions of years before modern mammals evolved.The newly identified species, named Megacauda sungei, lived during the Jurassic period. Researchers from the University of Chicago studied its well-preserved fossil and found that the animal had strong hind limbs, a flattened tail and specialised throat structures. Their findings were published in the journal Natureon on Wednesday.The animal belonged to an extinct group called docodonts, which were close relatives of mammals during the Mesozoic Era. It measured around 40 to 50 centimetres in length and weighed between one and two kilograms. Its physical features suggest that it spent time both on land and in water, much like modern semi-aquatic mammals.What makes the discovery important is the combination of its swimming adaptations and feeding structures. The fossil contains del...