A paleontologist called Javier Luque has announced a discovery that changes the crab family significantly. The discovery might force scientists to rethink the definition of a crab according to the team. The group of researchers, led by Luque, have announced the discovery of hundreds of “exceptionally well-preserved” specimens from rock formations in Columbia and the US.
The specimens date back to the mid-Cretaceous period 90 to 95 million years ago. The massive group of fossils includes hundreds of tiny comma shrimp fossils, several carideans, and a new branch of evolution for crabs. The new crab specimen was dubbed Callichimaera perplexa and is the earliest example of a swimming arthropod.
The name of the creature translates to “perplexing beautiful chimera.” It’s about the size of a quarter and has large compound eyes with no sockets, bent claws, leg-like mouth parts, and exposed tail, and a long body. The team says that these features are typical of crab larvae from the open sea.
That suggests that some of the crabs may have retained larval traits into adulthood, amplified them, and developed a new body architecture. This evolutionary process is caleld “heterochrony.” Luque says that the new crab species is so strange that it could be considered the platypus of the crab world.
Discoveries of this type rarely happen in tropical regions according to Luque. He says that the typically dense ground cover hides rock formations and makes accessing fossils difficult.