Javier Luque's soul mate is not just any other crab. His legs are not slim and long as the chamois of most crabs, but rather huge, beating paddles. His tank, the hard upper shell of his body, is not round, but oblong, more like a lobster. His eyes are not the typical pinpricks of crustaceans, but soft and glassy spheres are so huge that they would look like the size of a football for an average person. But Luque – who is worth mentioning – a human and not a crustacean – loves this crab. "This animal came without asking like a happy stroke into my life," says Luque. "I know we were meant for each other."
Luque, who works as a postdoctoral palaeontologist at the University of Alberta's Faculty of Biological Sciences and Yale University, named the newly described and very confusing Crab Callichimaera perplexa (19459003), or "confusing beautiful chimera", in homage to his peculiar hodgepodge of traits, according to a study published on April 24, 2019 in Science Advances . The name refers to the chimera of Greek mythology: a creature with a lion's head, a goat's body and a serpent's tail. This strange crab is as frightening as its namesake, but on a smaller scale.
The chimeric fossil arrived in Luques' life in 2005 when he studied geology. In search of fossils in Pesca, a city in the Colombian Andes, Luque and a friend had caught their breath after a long day in the field when they went home. As any budding geologist does, Luque pounded a nearby rock that split and revealed a layer crammed with hundreds of crustaceans. As Luque looked more closely, he recognized many fossils of coma shrimp and ammonite and, as he initially thought, a strange kind of spider with eight flappy legs and huge, bulky eyes. But as he got closer, he saw that the creature had pliers.
Luque called several fossil crustacean experts to find out if anyone could detect his bizarre discovery. To his surprise, everyone else was equally surprised by the perfectly preserved specimen. "If you can amaze the world's most experienced fossil crustacean experts, imagine how stunned I was!" Says Luque. The creature pierced him so deeply that Luque switched the gears of dinosaurs to prehistoric crustaceans. Officially a crab – though technically a mystery – Callichimaera represents a novel branch in the ancestral tree of the modern crab, although its body parts have an uncanny resemblance to animals of other groups. For this reason Luque calls it "the duckbill of the crab world".
One of the most bizarre features of the quarter-sized crab is its mysteriously huge eyes, which are likely to pivot freely and are too large to be picked up by an eye socket. Luque thinks she is very cute. "We believe the chimera has evolved similar to an axolotl, where it kept its baby features," says Luque. "That's why it looks like a pocket Pokémon." He says these eyes indicate that Callichimaera was a predator, as scavengers have little vision of good eyesight. "If you had such big eyes, you would actively use them," he says. The crab could have eaten on prawns, which Luque calls "the shrimp world noodles".
While most long-legged crabs crawled on the seabed, swamped Callichimaera . His elongated body was much more hydrodynamic than a normal crab, and his oarlike legs made him paddle through the water. "Most crabs in the world are crawling animals," says Luque. "But this one was a dreamer! It dared to swim like a bird in the water column. Not many crabs do that.
In addition to its evolutionary absurdity Callichimaera has an even greater significance as a fossil discovery in the tropics. It is understandable that few explorers go to the tropics to find fossils, as the region has dense vegetation layers and harsh weather that can make a fast work of a fossil. Because of this lack of focus, the researchers know, says Luque, little about the prehistoric animals of these regions. "We're starting to scratch the tip of an iceberg," he says, adding that tropical research institutions often lack the budget and resources available to North American, Asian and Australian institutions.
At the moment, Luque will continue working to investigate his stupid soul mate. He hopes to see how the creature swam, what it ate, and above all how it saw the world. When Luque is in bed at night, he often can not sleep because of the huge, shaky and unhappy eyes of the crab. "What did you use those eyes for?", Luque almost gets into the phone. "I have to know it."