Researchers at the University of Texas at Austin say they have identified the world’s oldest bug. The specimen is the ancestor of a thousand footworm found on the Scottish island of Kerrera, dating back 425 million years. The team says the discovery means the insects went through a rapid evolutionary phase.
“Worm” is a fairly casual term, but in this case, the team says, it refers to any insect, cobweb, or any other reptile. This is a fairly broad concept, but what is even more impressive is that this fossil is the oldest. The specimen is an extinct thousand-footed animal named Kampecaris obanensis. Although the fossil itself was discovered as early as 1899, the date has now been accurately determined.
To do this, the team conducted a radiometric measurement of zircon in the sediment. Zirconise is a very small mineral particle, very strong, so they can withstand a variety of geological events, and these geological events can allow them to withstand the test of time, making them the perfect time capsule.
Using this process, the team dated the zircon from three fossil sites in the UK, all of which had some of the earliest specimens of thousand-footed animals. As mentioned earlier, Kampecaris is found to be the oldest, 425 million years old. The fossils from the second site, Ludlow, are 420 million years old, and the rest of the fossils from Cowie are 414 million years old.
The team says the findings raise interesting questions about the evolution of insects. Other fossil evidence suggests that insects were widespread 407 million years ago, and that 385 million years ago, giant insects and related biomes flourished in forests. This suggests that insects have undergone quite rapid evolution in about 40 million years. This seems to be a rapid evolution, from these mountain valleys, down to the lowlands, and then to global evolution.
Interestingly, the team also believes that the fossils described here are the oldest worm fossils ever found, and that the older worm fossils have not been found in the older sediments, which hold other delicate fossils.
That is, this assumption conflicts with another method called molecular clock dating. This technique estimates the occurrence time of the type of substance based on traceability of DNA variability. According to molecular clock, the age of the thousand-footworm should be about 500 million years, 75 million years older than these fossils. Of course, the researchers did not claim that their claim symline was irrefutable. Instead, they say they’re just making assumptions that can be tested in future work.