Millipede breaks leg record – researchers discover the world’s first millipede with more than a thousand legs –

Legged crawler: In Australia, researchers have discovered a millipede with 1,306 legs for the first time – an animal record. Because the longest known Myriapod species had a maximum of 750 legs. The way of life of the new species “Eumillipes persephone” is also unusual, because the animal, which is just under a millimeter thin, lives up to 60 meters underground. It was only after drilling that it came to light, as the scientists report.

Millipedes are among the oldest land animals on our planet. More than 400 million years ago, their ancestors settled on the earth’s land and lived on carrion, organic material and smaller prey. Today the myriapods have spread over almost the entire world and developed various survival strategies. Some curl up into solid balls to ward off enemies, others produce highly toxic alkaloids and other juices, which in turn are used by other animals for self-medication or defense.

Electron micrograph of the head and mouthparts of Eumillipes persephone. © Marek et al./ Scientific Reports

1,306 legs – the first real Millipede

But all millipedes seemed to have one thing in common: Contrary to what their name suggests, these arthropods usually only have a few dozen to a few hundred legs. “A Myriapod with more than 750 legs has never been described,” explain Paul Marek of the Virginia Institute of Technology and his colleagues. This previous record holder is the rare species Ilacme plenipes, native to California, with 105 to 171 double segments.

But now Marek and his team have discovered the first millipede that lives up to its name: The species baptized Eumillipes persephone is the first Myriapod to have more than a thousand legs. The extremely thin animal is around 95 millimeters long and has a total of 1,306 legs on its 330 double segments, as the researchers found. This millipede also belongs to the subgroup of bipedes, which has more than one pair of legs per segment.

60 meters deep underground

The new millipede was found in an unusual location: the research team discovered it in a 60-meter-deep borehole in Western Australia that an oil company had left behind after an exploratory drilling. “A total of eight specimens of this new species were recovered in three such boreholes from depths of 15 to 60 meters,” report Marek and his team. The huge Myriapod is therefore at home deep underground.

Other features of the small millipede also match this underground way of life: it no longer has eyes, but instead particularly long antennae. In addition, its body is pale, compressed on the sides and the tiny legs are relatively short, even for a bilipod, as the researchers explain. They suspect that this species has adapted to locomotion and life in the narrow rock pores of the deep underground.

Eumillipes has many legs, but these are very short, as this electron microscope image shows. © Marek et al./ Scientific Reports

Adaptations to life in the rock

The many legs and telescopically interlocking body segments also help the millipede to move forward. “The increase in the number of legs probably helps to give the animal more thrust when crawling through small cracks and openings,” say Marek and his colleagues. As they observed, Eumillipes first scanned the area with its enlarged antennae in order to find a suitable crack. Then the animal squeezes through with the help of its legs and flexible segments.

These adaptations to life underground also feature several other millipedes, including former leg record holder Ilacme plenipes. However, because these species are only very distantly related and occur thousands of kilometers apart, the scientists see this as evidence of convergent evolution: Within the Myriapods, such adaptations have arisen several times independently of one another.

Driven underground by the climate

It is likely that the ancestors of Eumillipes once lived above ground, like most millipedes. But then a gradual change in the climate could have driven them underground. “The climatic conditions on the surface fluctuated considerably over the course of millions of years, but remained relatively stable underground,” said Marek and his colleagues. The cracks and pores in the rock could therefore have become a refuge for the ancestors of the Myriapod.

Today it is sometimes more than 46 degrees hot on the surface of the Western Australian site during the day and it hardly rains. In the underground, however, it remains cool and moist all year round. What the millipede eats there is still unknown. Its beak-like mouth in combination with the subterranean way of life suggests that eumillipes feed mainly on fungal tissue, as the scientists explain. (Scientific Reports, 2021; doi: 10.1038 / s41598-021-02447-0)

Quelle: Nature Scientific Reports

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