A very ancient crab has been found preserved in amber dating back about 100 million years and has been described as being a “spectacular” find. There have been several previous discoveries of living creatures found in amber but they were all from land. This newly discovered crab specimen is actually the oldest ever discovery of an aquatic creature found trapped in amber. Furthermore, it is the most complete fossil of a crab that’s ever been found.
This new species of crab, which has been named Cretapsara athanata, was initially found in Kachin State in the northern part of Myanmar. The Longyin Amber Museum became in possession of the amber specimen in 2015 when they got it from a vendor in Tengchong, China, close to the Myanmar border. It has recently been analyzed by scientists from China, Canada, and the United States.
The crab was exceptionally tiny (probably a baby), measuring just 5 millimeters in length. Computerized tomography scans showed it in greater detail, such as its antennae as well as its gills and fine hairs on its mouth.
Javier Luque, who is a postdoctoral researcher in the Department of Organismic and Evolutionary Biology at Harvard University, described the incredible condition that the crab was in, “The specimen is spectacular, it is one of a kind. It's absolutely complete and is not missing a single hair on the body, which is remarkable.”
As for how a crab ended up trapped in amber, the experts believe that it probably lived in fresh water or brackish water that is found on the ground in forests. It was more than likely not a marine crab but not completely land-based. It may have possibly been migrating onto land after it was born in the water and that’s how it might have ended up in the amber. Fossils from crabs dating back to more than 200 million years ago have previously been found; however, remains of non-marine crabs are very rare and mostly incomplete when they are discovered.
Additionally, the discovery proves that crabs transitioned from the sea to land and fresh water while the dinosaurs were still living – a transformation previously thought to have occurred during the mammal era. “In the fossil record, non-marine crabs evolved 50 million years ago, but this animal is twice that age,” Luque noted.
A picture of the crab inside of the amber can be seen here.
The study was published in the journal Science Advances where it can be read in full.