This little crustacean trapped in amber tells a different story about the evolution of the crab | Smart News
A team of scientists have discovered the oldest aquatic animal preserved in amber. The little crab enclosed in the resin of trees is over 100 million years old and dates back to the Cretaceous era, according to the study published this week in Scientists progress. The find, the most complete fossilized crab ever seen, is helping researchers replenish themselves when crustaceans began to migrate out of the sea.
Scientists can reconstruct what life looked like millions of years ago from preserved specimens like amber fossils and bones. Insects, plants, feathers, and microorganisms are the most likely specimens to be found trapped in amber. However, finding an aquatic creature fossilized in resin is extremely rare. “Finding a crab in amber is like finding a needle in a haystack,” Florida International University biologist Heather Bracken-Grissom, not involved in the study, told Riley Black. National Geographic.
The animal is so well preserved that its compound eyes, claws, articulated legs and gills are visible in detail, reports National Geographic. Using micro-scanners, the international team visualized the crab’s body in 3D and even imaged its mouthparts lined with fine hairs. It is not known if the five-millimeter-long crab is an adult, juvenile or baby, reports by Gizmodo George Dvorski.
The crab also has well-developed gills, suggesting it was an aquatic to semi-aquatic animal, according to one declaration.
Based on the crab’s anatomy, the research team determined that the tiny crustacean was a new species and dubbed it, Cretapsara athanata. The scientific name refers to the era of dinosaurs in which the crab lived and Apsara, a spirit belonging to South and Southeast Asian mythology, reports Katie Hunt for CNN. The new species belongs to a group of still living crustaceans called Eubrachyura. C. athanata is part of a new branch in the crab family tree, by declaration.
The absence of sand in the fossil and the way the sap flowed over the crab suggests that the animal lived far from the beach and in fresh or brackish water, National Geographic reports. It is also possible that the crab migrated as the red crabs on Christmas Island do to release their offspring into the ocean and then return to land, CNN reports.
The evolutionary movement of the crab out of the ocean water was a huge side step. This meant that the animal had to adapt to living in brackish or fresh water by changing the way it regulated water, breathed and kept it from drying out, said Javier Luque, a paleontologist at the University of Yale and first author of the study. National Geographic.
Evidence shows that crabs have mastered habitat on land and in brackish and fresh waters at least twelve times since the dinosaur era. Because of this, their gills have evolved to have lung-like tissue that allows them to breathe in and out of water. C. athanata had no lung tissue and instead had well-developed gills, which suggests he did not live entirely on earth, a statement said.
“Now we were dealing with an animal that is probably not marine, but also not entirely terrestrial,” Luque said in a statement. “In the fossil record, non-marine crabs evolved 50 million years ago, but this animal is twice that age.”
Researchers say new fossil evidence brings this division between marine and non-marine crabs from the Age of Mammals, also known as the Cenozoic, back to the Age of Dinosaurs, CNN reports. Crabs began to bypass the land when dinosaurs roamed the Earth and not after the dinosaurs became extinct.
Amber was found in Myanmar, where most of the world’s amber fossils are sourced, and currently resides in the Longyin Amber Museum in China. In recent years, ethical concerns regarding the collection, study and purchase of highly prized amber in conflict zones as well as the repatriation of fossils to preserve the country’s natural history have been raised, National Geographic reports. In their article, the authors write: “Researching specimens collected before the conflict and acknowledging the situation in Kachin State will serve to raise awareness of the current conflict in Myanmar and the human cost that ensues,” according to CNN .