These ancient spiders had what? Kansas researcher says new species is key to evolution

When University of Kansas researcher Paul Selden first examined an unknown species of arachnid found in 100-million-year-old Burmese amber from Myanmar, the specimens had some familiar characteristics.

They look similar to modern-day spiders, and have fangs, four walking legs and silk-producing spinnerets.

But the creature, which likely walked the Earth more than 100 million years ago, also had a tail.

“Any sort of flagelliform appendage tends to be like an antenna,” Selden said in a KU News Service report. “It’s for sensing the environment. Animals that have a long whippy tail tend to have it for sensory purposes.”

Selden, the director for the Paleontological Institute at the University of Kansas, and other researchers from across the world published a study of the new species in Nature Ecology & Evolution this month.

According to their publication, the origins of spiders have been difficult for scientists to nail down. But one of the reasons researchers are so excited about the new discovery is that it appears to be a missing evolutionary link.

Selden and his colleagues have already studied an arachnid with a similar tail, thought to have existed more than 290 million years ago. But those animals didn’t have spinnerets.

Modern-day spiders don’t have tails, but do have silk-producing spinnerets.

With its tail and its spinnerets, researchers now believe the recently-discovered specimens — four 2.5 millimeter long animals with a 3-millimeter-long tail were found — represent an animal order that falls between. Scientists have called this new animal Chimerarachne, after the mythological Greek creature, Chimera.

“The ones we recognized previously were different in that they had a tail but don’t have the spinnerets,” Selden said. “That’s why the new one is really interesting, apart from the fact that it’s much younger — it seems to be an intermediate form. In our analysis, it comes out sort of in between the older one that hadn’t developed the spinneret and modern spider that has lost the tail.”

Selden told KU that it’s likely the species lived in the bark or moss of the trees found in Myanmar’s backcountry.

He said he hadn’t ruled out that descendants of the animal may still exist in remote locations that have yet to be discovered by researchers.

This story was originally published February 5, 2018 at 2:40 PM with the headline "These ancient spiders had what? Kansas researcher says new species is key to evolution."