However, all of these creatures were terrestrial lubbers that you might expect to find in a tree trunk or branch. Now, scientists have found the oldest aquatic animal preserved in amber, and it is the most complete crab fossil ever discovered.
“The specimen is spectacular, it’s unique. It’s absolutely complete and it doesn’t lack a hair in the body, which is remarkable,” said Javier Luque, a postdoctoral researcher in the Department of Organizational and Evolutionary Biology at Harvard University. a press release. He was the lead author of the study published Thursday in the journal Science Advances.
Chinese, American and Canadian scientists working on the amber specimen, native to northern Myanmar, named the small crab Cretapsara athanata. The name refers to the Cretaceous, the period of the time of the dinosaurs during which this crab lived, and Apsara, a spirit of clouds and waters from South and Southeast Asian mythology. The name of the species is based on “athanatos”, which means immortal in Greek, referring to its realistic conservation in amber.
In appearance, the creature from 100 million years ago superficially resembles the crabs that now scatter along the shores. Computed tomography scans revealed delicate parts of the body such as antennae, gills and hairs up to the mouth parts. The creature was only 5 millimeters tall long and probably a crab baby.
While the oldest crab fossils date back to the Jurassic period more than 200 million years ago, non-marine crab fossils are scarce and largely incomplete.
The researchers said Cretapsara shows that crabs made the leap from the sea to land and fresh water during the age of the dinosaurs, not during the age of mammals, as previously thought, pushing the evolution of crabs. not sailors much further back in time.
“In the fossil record, non-marine crabs evolved 50 million years ago, but this animal is twice that age,” Luque said.
Dinosaur-era amber fossils are only found in deposits in the state of Kachin in northern Myanmar, and in recent years ethical concerns have emerged about the region’s amber origin.
The authors of this study said that the Longyin Amber Museum acquired the amber specimen from a vendor in the city of Tengchong, near the border with Myanmar, in southern China, in August 2015.
They hoped that “researching specimens collected before the conflict and recognizing the situation in Kachin state will serve to raise awareness of the current conflict in Myanmar and the human cost behind it.”