Itsy bitsy spiders discovered in 100million-year-old amber

DEEP in a tropical rain forest, during a time when dinosaurs walked the Earth, four itsy bitsy spiders crawled down a tree, got stuck in some sticky resin and never climbed up again.

Some 100 million years later, blocks of amber containing their fossilised forms wound up on the desks of two scientists in China. Both researchers looked at the perfectly preserved animals and came to the same conclusion: This was an entirely new kind of animal.

They introduced their discovery, dubbed Chimerarachne yingi, in a pair of papers published Monday in the journal Nature Ecology and Evolution. With its curious mix of ancient and modern traits - a long, skinny tail inherited from a distant arachnid ancestor, but a silk-producing organ like those found in spiders today - the tiny chimerarachne, or “chimera spider,” is not a member of the immediate family. But it is one of modern spiders’ closest cousins, and it presents some intriguing hints at how they evolved.

The C. yingi fossils were uncovered by amber miners in northern Burma, sold to dealers, then purchased by researchers at the Chinese Academy of Sciences. By coincidence, two sets of the fossils became available around the same time, and Bo Wang and Diying Huang - colleagues in the academy’s paleobiology lab - began to analyse them almost simultaneously. Neither was aware of what the other was up to until they submitted their studies for publication. Happily, their results were close enough that the journal opted to publish both papers.

Both describe creatures so small they could fit on the tip of a fine-point pen. — Washington