An extraordinary new species of arachnid, resembling a spider with a tail, has been discovered in amber from Myanmar (formerly Burma), of mid-Cretaceous age, around 100 million years ago. The arthropod has been named Chimerarachne (Chimerarachne yingi) after Chimera, a monster from Greek mythology who was made of the parts of more than one creature.
“There’s been a lot of amber being produced from northern Myanmar and its interest stepped up about ten years ago when it was discovered this amber was mid-Cretaceous; therefore, all the insects found in it were much older than first thought,” says palaeontologist and arachnologist Paul Selden of the University of Kansas.
“It’s been coming into China where dealers have been selling to research institutions. These specimens became available last year to Nanjing Institute of Geology and Paleontology.”
It resembles a spider in having fangs, male pedipalps, four walking legs and silk-producing spinnerets at its rear. But the twist lies in its back end which extends to a long flagellum. Of all known species of spider that live today, none have been found with a tail, although some relatives of spiders, the vinegaroons, do have an anal flagellum. Four new specimens of C. yingi have been found, and all are tiny, about 2.5 millimeters body length, excluding the nearly 3-millimeter-long tail.
It was added that the spider’s remote habitat means it is possible that tailed descendants may still be alive in Myanmar’s back country to this day.
Professor Selden adds: “It makes us wonder if these may still be alive today. We haven’t found them, but some of these forests aren’t that well-studied, and it’s only a tiny creature.”
Their findings and observations are published in an article for Nature: Ecology And Evolution, “Cretaceous arachnid Chimerarachne yingi gen. et sp. nov. illuminates spider origins”.
In studies published side-by-side in Nature Ecology and Evolution, one team argued that male sex organs and silk thread-producing teats link the creature to living spiders.
The other team pointed to the long tail and a segmented body to argue that Chimerarachne yingi belongs instead to a far more ancient and extinct lineage at least 380 million years old.