Researchers announced on Monday the discovery of a odd 100 million-year-old spider fossils.
But the spider - encased in fossilised tree sap known as amber - also had a long tail.
Researchers have uncovered a new species of arachnid that lived during the mid-Cretaceous age, around 100 million years ago.
This spider confirms a prediction made a few years ago by the researchers when they described a similar tailed arachnid, which resembled a spider but lacked spinnerets.
The researchers can not confirm what the unique tail would have been used for, but they speculate it may have helped them navigate their surroundings.
The recent discovery of four of these creatures in northern Myanmar, trapped in amber for 100 million years, has blown the door wide open for researchers to establish a link between ancient and modern day arachnids, the BBC News reported. Comparison with fossils subsequently unearthed showed that this newly classified branch of arachnids differed from spiders - the Araneae - in several structural ways, notably in the positioning of silk-producing spigots, and a tail-like appendage, known as a telson, at the end of the abdomen.
Amber preserved in exquisite detail these 100-million-year-old close relatives to spiders.
Spiders as a group date back to more than 300 million years ago.
Researchers of the latest study found out that the modern spiders might have a connection with the prehistoric arachnids.
Scientists say the spiders were a missing link between the even more ancient uraraneids and primitive living spiders. In addition to its tail, "the new animal resembles a spider in having fangs, male pedipalps, four walking legs and silk-producing spinnerets at its rear".
Around 15 years ago they discovered that Burmese amber was older, which resulted in a huge amount of new material becoming available for study.
From what they can see, it looks like a spider with a tail from another creature attached to it.
"The ones we recognized previously were different in that they had a tail but don't have the spinnerets", said Selden.
Spiders have also used their silk to make trails to guide them back to their homes and lines for diverging or trapping prey, among other purposes.
The specimens are all tiny - about 2.5 millimeters in body length - excluding the almost 3 millimeter-long tail.
"However, like all spiders it would have been a carnivore and would have eaten insect eggs, I imagine".
With its tail and its spinnerets, researchers now believe the recently-discovered specimens - four 2.5 millimeter long animals with a 3-millimeter-long tail were found - represent an animal order that falls between. "These are gorgeous creatures and would probably never harm a human, like 99.99% of the spiders", he said. He mentioned that it could be possible that these tiny spiders still exist in Myanmar today - or at least their descendants.
While the tailed spider was capable of producing silk due to its spinnerets, Selden said it was unlikely to have constructed webs to trap bugs like many modern spiders.
Selden told KU that it's likely the species lived in the bark or moss of the trees found in Mynamar's backcountry.