A new species of spider has fascinated specialists. And is not for less. It is a hundred million years old, and has reached us almost intact thanks to the resin that trapped it in a death trap that turned to amber over time. Some of its characteristics bring it closer to modern spiders: silk- producing organs on its back, eight legs, pedipalps, fangs … But others move it away, especially its long tail or flagellum, which gives it a nightmare appearance similar to that of the uropygians, an order of scorpion-like arachnids that inhabit tropical and subtropical regions.
The strange creature lived a hundred million years ago, in the middle of the Cretaceous, and comes from northern Burma. Their finding has been published in the journal Nature Ecology & Evolution by an international team of scientists led by Paul Selden, from the Institute of Paleontology belonging to the Department of Geology at the University of Kansas.
A link in the evolutionary chain
Its striking appearance and peculiar features make its discoverers think that it is an intermediate step in the evolution of arachnids, a transition between the tailed species that lived throughout the Devonian and Permian (between 400 and 250 million years ago years) and those that gave rise to the current spiders.
The four specimens preserved in amber that have been discovered have been named Chimerarachne yingi in reference to the chimera, a monster from classical mythology that had the head of a lion, the belly of a goat and the tail of a dragon. It is a way of highlighting the character of mixture between the old and the new of these animals. But they would not have scared us very much, perhaps we would not have seen them: their body was only 5.5 millimeters long: 2.5 in body, and 3 in tail, an appendix that according to its discoverers would have had sensory antenna functions to explore. the environment.
Mixed anatomy
Scientists make guesses about the life of these tiny arachnids. To begin with, how did they end up imprisoned in amber? Paul Selden believes it is because they lived on or near tree trunks. “Amber is fossilized resin, so if a spider gets trapped in it it is because it lives under the bark or in the moss that grows at the foot of the trees.”
Chimerarachne yingi possessed organs intended for the production of silk, but it is not known whether it built cobwebs. According to Selden, “maybe he used it to wrap the eggs he laid, build burrows, make hammocks or leave clues to find his way around. These spiders arose before their descendants began to weave webs to trap insects. The spiders began to set these aerial traps when flying insects emerged, not before, it was an adaptation to hunt. I suppose this species was carnivorous and fed on insects, but I don’t know for sure ”.
The University of Kansas researcher thinks that, given the remoteness of the Chimerarachne yingi habitat, there could be descendants of it in the Burmese region where it lived.
“We know a lot about what modern Burma was like in the Cretaceous. It was covered by a tropical rain forest in which numerous species of arachnids similar to the current ones thrived. In that region there are still many little explored areas, and we are talking about a very small animal “.
Perhaps there is a little spider with a tail waiting for us at the foot of any Burmese tree.
Photo (University of Kansas): One of the Chimerarachne yingi specimens.
