What do the Tour de France and fossils have in common? | Susannah Lydon

Sport and palaeontology rarely overlap, but a new study shows ancient arthropods may have used the same slipstreaming techniques as elite cyclists

Trilobites are common fossils. Resembling nothing so much as a glorified woodlouse, these animals teemed in our oceans for millions of years. The first fossils are around 520 million years old, while the final demise of one last group of survivors took place 250 million years ago, in the Earth's biggest known mass extinction event. In size, they varied from tiny planktonic forms a millimetre long to the mighty Isotelus rex, more than 70 cm long. Some swam and ate plankton, others were scavengers or predators which roamed the sea-floor.

There are thousands of species of this group of extinct arthropods (invertebrates with an exoskeleton and jointed limbs), but they all conform to a strict body plan. From front to back, they have a head (cephalon), a body (thorax) made up of segments, and a tail (pygidium). The three longitudinal lobes along their body, one down the middle and one on each side, are what give them their name. When exceptionally-preserved specimens are found, the details of their limbs, underneath their body, are revealed: they have a pair of antennae, followed by many two-branched limbs down the rest of their body. If your love of palaeontology stems, in part, from the alien aesthetic qualities of life from the deep past, then trilobites have all the wonderfully Giger-esque features you could hope for. In fact, one of the xenomorphs in Prometheus is known as the Trilobite, despite ending up looking much more like a cephalopod.