An ancient worm that lived 535 million years ago had thorn-like spines on its body, a mouth encircled by teeth, and an armoured body, but it only measured about 0.07 inches (2 millimetres) in length, according to a new research.
The worm called Eokinorhynchis rarus was found Nanjiang County, located in China’s Jiangsu province where there can now be seen steep mountains that formed about 200 million years ago.
However, during the Cambrian period (about 543 million to 490 million years ago), the area was covered by a shallow and rich in phosphate ocean that was home to the marine worm Eokinorhynchis rarus. Researchers say that the phosphate in the ocean helped fossilise the worms millions of years ago.
Shuhai Xiao, author of the study and a professor of geobiology at Virginia Polytechnic Institute and State University in Blacksburg, Virginia, commonly referred to as Virginia Tech, said that he and fellow researchers excavated approximately half a ton (500 kilograms) of rocks from the site in Nanjiang County.
The researchers took the rocks back to the lab and dissolved them using acetic acid, which had no effect of the fossils that resided inside the rocks. Once the rocks were dissolved, the Eokinorhynchis rarus fossils were brought to light.
After analysing the worms, the researchers found that they had twenty armoured body segments enclosed by spiky plates, and five larger pairs of spines could be found on the Eokinorhynchis rarus’ trunk.
The ancient worm Eokinorhynchis rarus is similar to a group of marine invertebrates called kinorhyncha – small (1 mm or less) armour-plated marine invertebrates that can be found in mud or sand; they are also known by the name of mud dragons. Both the Eokinorhynchis rarus and the mud dragon have spines, but the spines of Eokinorhynchis rarus are much larger, according to the researchers. The two creatures also have segmented bodies.
Because of all the similarities, scientists believe that Eokinorhynchis rarus may the ancestor of the kinorhyncha, or mud dragons. Although they have been around for half a billion years, the history of the mud dragon is poorly documented, which is why the new discovery is very important, Xu said.
The researchers published their findings November 26 in the journal Scientific Reports.
Image Source: nature