Ancient Arachnid Fossil Was Spider-like But Lacked Spinnerets

Posted on March 31, 2016

Idmonarachne brasieri

Scientists have discovered the fossil of an ancient spider-like creature. The 305-million-year-old fossil shows an arachnid that possessed spider-like fangs and limbs but lacked spinnerets.

The new species was named Idmonarachne brasieri. It was named after Professor Martin Brasier, University of Oxford. The fossil was found in Montceau-les-Mines, France. It was preserved in 3D and scanned. There is little knowledge of spider predecessors and the new fossil could provide insights into character acquisition early in their evolution.

Lead author Russell Garwood from The University of Manchester says in a statement, "Our new fossil occupies a key position in the evolution of spiders. It isn't a true spider, but has given us new information regarding the order in which the bits of the anatomy we associate with spiders appeared as the group evolved."

The researchers believe that arachnids like Idmonarachne brasieri could produce silk but they could not spin it using the specialized appendages spiders have - the spinnerets. National Geographic reports that the ancient arachnid "acts as a bridge between early spider-like creatures brewing up blobs of silk and the skilled weavers that we see today."

BBC News reports that the earliest known spider comes from the exact same fossil deposit. Garwood tells BBC News, "The earliest known spider is actually from the same fossil deposit - and it definitely has spinnerets. So what we're actually looking at is an extinct lineage that split off the spider line some time before 305 million years ago, and those two have evolved in parallel."

A research paper on the findings was published here in the journal, Proceedings of the Royal Society B.

Image: Proceedings of the Royal Society B