Scientists in Australia They have identified the oldest fossil fingerprints of an animal similar to a reptiledated about 350 million years ago.
The discovery suggests that after the first animals emerged from the ocean about 400 million years ago, they evolved the ability to live exclusively on land much faster than was thought.
“We thought that the transition from fin to limb took much longer.”said the paleontologist at the State University of CaliforniaStuart Sonsido, who did not participate in the new research.
Previously, the oldest reptile traces, found in CanadaThey dated 318 million years ago.
Australia’s old footprints were found in a recovered sandstone slab near Melbourne and show feet similar to those of a reptile with long fingers and curved claws.
Scientists estimate that the animal was about 80 centimeters long and may resemble a modern monitor lizard. The findings were published on Wednesday in Nature.
The curved claws are a crucial identification track, said the study co -author and paleontologist Per Ahlberg of the University of Uppsala in Sweden.
“It is an animal that walks”said.
Only animals that evolved to live only on land developed claws. The first vertebrates, fish and amphibians, never developed hard nails and continued depending on the aquatic environments to put eggs and reproduce.
But the branch of the evolutionary tree that led to modern reptiles, birds and mammals, known as amniotas, developed feet with nails or claws suitable for walking on the mainland.
“This is the earliest evidence we have seen from an animal with claws”he said mired.
At the time the old reptile lived, the region was warm and humid and vast forests began to cover the planet. Australia was part of the Gondwana supercontinent.
The fossil footprints record a series of events in a single day, said Ahlberg. A reptile ran on the ground before a slight rain fell. Some rain drops partially obscured their footprints. Then, two more reptiles ran in the opposite direction before the ground harden and covered with sediments.
The fossil “footprints” are beautiful because they tell you how something lived, not only how it was, ”said co -author John Long, paleontologist at the University of Flinders in Australia.