A sandstone boulder in the north of England contains a section of the giant millipede Arthropleura.
Neil Davies is a person.
The length of a small car from before the time of the dinosaurs was dated by scientists. The animal is thought to have broken the record for the largest arthropod, a group of arthropods that include insects, lobsters and spiders.
The Journal of the Geological Society describes the fossil, which is about three feet long, in England. It is thought to be three times as long as the one found, with a section weighing 50 kilograms and measuring nearly 9 feet in length.
Neil Davies, an Earth scientist at the University of Cambridge, told NPR that he and a group of students almost stumbled upon a fossil.
The group went on a "social trip" to the area. Davies says he knew the area well from previous holiday visits.
He says that they saw a boulder that had fallen from the cliff and then saw a big crack.
Davies said that he and his colleagues were unsure of what they had found, but were convinced of it when they returned the next morning.
This type of animal lived during the Carboniferous Period, when England was much closer to the equator.
There are a number of preserved trackways that are believed to be from the creature, but only two other relatively intact fossils have ever been found. The one Davies and his colleagues found was larger than the others.
Davies says that the bodies of giant millipedes tend to come apart after they die. He thinks that what they found is a shell that was thrown away after the animal's death.
He says that people have found fragments of skeletons, individual legs or individual bits of skeleton, but not something like this.
He says that the area where the fossil was found is mostly sandstone, which is not great for preserving fossils.
An artist's rendering.
Neil Davies and Sarah Collins are related.
It is surprising that this has been preserved. It suggests that there may be more similar things in places where people have not looked for fossils before.
The sea scorpion was thought to be the largest arthropod, but the fossil appears to have knocked it out of the top spot. Most of the sea scorpions lived in shallow water than in the open sea.
Davies' find is a new and rare example of an extinct giant millipede, and it might help shed light on why these creatures were so big. The late Carboniferous and Permian periods have been thought to have high levels of atmospheric oxygen. Some of the trackways and fossils that Davies and his colleagues found were found before that peak.
He says that the oxygen doesn't peak until after the things go extinct. They don't match up.
He says that the verdant landscape at the time might have given Arthropleura the chance to get bigger.
Davies says that they might be interacting with a predator. It doesn't seem to be oxygen, and it seems to be something more environmental.