In Scotland, found the fossil of the oldest millipedes in the world – it is 425 million years old. According to scientists from the University of Texas at Austin, this is the oldest arthropod found on Earth. Research results are published in the journal Historical Biology.
The centipede fossil, which is 425 million years old, has been found on the Scottish island of Kerrera. The find provides new data on the origin and development of insects and plants. Now it became clear that they evolved much faster than some scientists thought. The transition from local communities to complex forest ecosystems took place in just 40 million years.
“It’s a big leap from these tiny“ guys ”to very complex forest communities, and it didn’t take that long,” says Michael Brookfield, a fellow at Jackson’s School of Geophysical Research at Austin University. “It seems that the rapid course of evolution first started from the mountain valleys, then descended to the lowlands, after which it already spread throughout the world”.
True, the centipede age from Scotland turned out to be 75 million years less than the age that scientists assigned to it using the molecular clock dating method.
Molecular clocks are a method of dating phylogenetic events (discrepancies between species or other taxa), based on the hypothesis that evolutionarily significant changes in monomers in biomolecules occur at an almost constant rate. Typically, nucleotide sequences of DNA and amino acid sequences of proteins are used for such calculations. The speed of mutations can be uneven and varies for different species, because of which the method gives only approximate results.
Also in Scotland, a fossil of an ancient stem plant was discovered, whose age was also 425 million years (it is also 75 million years younger than the estimated age by the molecular clock method).
It is possible that there are older fossils of both beetles and plants. But, according to Brookfield, the fact that they were not found may indicate that the ancient millipedes and fossils of plants found in Scotland are the oldest specimens.
If this is the case, it also means that both insects and plants developed much faster than the molecular clock based timeline shows. Abundant insect deposits are only 20 million years younger than fossils. And 40 million years later, the first evidence appeared of thriving forest communities filled with spiders, insects, and tall trees.
To date, the samples, the technique of extracting zircons from ash mountain sediment was used.