Scientists find very old spider with tail

PARIS: Two teams of scientists on Monday unveiled a “missinglink” species of spider with a scorpion-like tail found perfectly preserved in amber in the forests of Myanmar, after at least 100 million years.

In studies published side-byside in Nature Ecology and Evolution, one team argued that male sex organs and silk thread-producing teats linked the creature to living spiders.

The other team pointed to the long tail and a segmented body to argue that Chimerarachne yingi belonged instead to a far more ancient and extinct lineage at least 380 million years old.

Either way, the researchers agree that C. yingi fills a yawning gap in the evolutionary saga of the nearly 50,000 species of spiders that spin webs and trap prey around the world today.

“It’s a missing link between the ancient Uraraneida order, which resemble spiders, but have tails and no silk-making spinnerets, and modern spiders, which lack tails,” said Bo Wang, a palaeobiologist at the Chinese Academy of Sciences in Nanjing and lead author of the study.

With a body length of about 6mm — half taken up by the tail – C. yingi is, truly, an itsy-bitsy spider.

The filaments made by four nipples extruding from the back end of its abdomen were probably not there to spin webs.

“Spinnerets are used to produce silk for a whole host of reasons: to wrap eggs, to make burrows, to make sleeping hammocks, or just to leave behind trails,” said Paul Selden, Wang’s co-author.

C. yingi also boasts pincer-like appendages, called pedipalps, used to transfer sperm to the female during mating, a signature trait of all living spiders.

Its whip-like tail or flagellum, also known as a telson, likely “served a sensory purpose”, said Wang.