The new specimen of spiders is a missing link between the ancient Uraraneida order, which resemble spiders but have tails and no silk-making spinnerets.
“It is a key fossil for understanding spider origins”, according to paleontologist Bo Wang of the Chinese Academy of Sciences.
Four new specimens of this mysterious species – which has been dubbed Chimerarachne Yingi – have been found so far. Thanks to Mother Nature’s great freeze-frame device known as amber, scientists have just discovered a remarkable new species of arachnid from 100 million years ago. But it’s not entirely certain that C. yingi is a Uraraneid, judging from the silk-producing organs which were more similar to those of modern spiders.
Being minuscule, given that each fossil was about 7-8 mm long, including the 5 millimeters of the tail, the animal was called Chimerarachne yingi, a reference to Himera, the hybrid monster of Greek mythology, because it is a curious mixture of old and modern characteristics.
Atypical, though, are the spiders’ long, slim tails, which measure about 3mm long and feature short hairs. The scientists got excited after getting hold of the first evidence of ancient tailed spiders. Dr Paul Selden of the University of Kansas said, “We haven’t found them, but some of these forests aren’t that well-studied, and it’s only a tiny creature”.
The tail’s function is unclear, but the researchers suspect it may have worked like a kind of antenna that the arachnid used to sense environmental cues. But at some stage modern spiders ditched the tail. Although their conclusions varied in terms of dating the ancient arachnids, they agreed that Silk-spinning spiders with and without tails co-existed for millennia.
For starters, in addition to fairly standard spider traits such as fangs and multi-segmented spinnerets that produce silk, there’s that tail. If they live in burrows and leave, they leave a trail so they can find their way back. And discovering new fossils could settle the debate. That makes them surprisingly young, Professor Selden said. This means that early arachnids had a mix of all these traits, which were selectively lost in their descendants, giving rise to the array of arachnids seen today.
Spiders went up into the air when the insects went up into the air. “Taken together, Chimerarachne has a unique body plan among the arachnids and raises important questions about what an early spider looked like, and how the spinnerets and pedipalp organ may have evolved”. “You’ve effectively got the typically South-East Asian tropical rainforest, but with these sort of living fossils in with them”.
The four fossils came from the amber mines of northern Myanmar – a treasure trove of fossils like a dinosaur tail trapped in amber, and ancient ticks that feasted on dino blood. He thought the presence of spinnerets pulled it to the side of spiders.
“Spinnerets are spiders so all of a sudden we’ve truly got the missing link”, he said. But experts disagree about how these fossils relate to modern-day spiders, because there’s something odd about their crumpled corpses: all four of them have tails.