Quirks & Quarks

A 305-million-year-old proto-spider fills fossil gap

High-tech imaging of an ancient fossil reveals an evolutionary cousin to true spiders

Primitive arachnid was nearly-but-not-quite a spider

3-D reconstruction of the proto-spider fossil (Garwood et al.)
A fossil arachnid found in eastern France has been determined to be an almost-spider, filling in an important gap in the evolutionary history of spiders. Canadian scientist Dr. Robert Atwood, from the Diamond Light Source Synchrotron in Didcot, England, used high-powered X-rays to create 3-D images of the rock-encased arachnid fossil. 

The images revealed that the animal's mouth parts, legs and body shape are similar to those of a true spider. There were important differences, however, in how the animal produced and used silk.

This arachnid may have used its silk to line a nest or protect eggs, but it did not have the spinnerets that would have allowed it to produce a web. It co-existed with real spiders for some time, but ultimately succumbed to extinction.

Related Links

- Paper in Proceedings of The Royal Society B
- University of Manchester release
- Diamond Light Source release
- BBC News story
- Livescience story