The first ancestor of scorpions and spiders was found in Africa

A study of fossils from an African archaeological site has revealed the ancestors of spiders, scorpions and horseshoe crabs, solving a decades-long paleontological mystery that essentially represents the past existence of all zoology. This work was a joint effort between the University of Lausanne, Switzerland, and the French National Center for Scientific Research (CNRS).

Horseshoe crabs, scorpions and spiders all belong to the lineage of arthropods that appeared on our planet about 540 million years ago. They are all part of a subgroup famous for creatures with pincers used to bite, grab prey, or inject venom – the chelicerae, which gives them the name Chelicerata. His ancestors were unknown until then.

The missing link of chelicerates

The mystery of the ancestors of chelicerates has occupied the minds of paleontologists for a long time, as no ancient arthropods were similar enough to modern representatives to indicate lineage. The period between 505 and 430 million years ago, in particular, was absent in fossils, complicating the issue.

Enter Lorenzo Lustri, a doctoral student at the University of Lausanne, who has been studying 478 million-year-old fossils from the Vasoata shale in Morocco. Remains were found in the area in the early 2000s, but some have not yet been described. Lustre was describing one of them, which dates back to the Cambrian period, and was surprised to notice its characteristics.

Its length ranges between 5 and 10 millimeters, and this species has acquired the scientific name Profuse endocrinitisand was described based on 100 specimens studied using X-ray scanners, allowing the creation of full 3D anatomical models.

Although the similarity is enough to prove lineage, deeper studies will be needed to establish a more solid link and understand the evolution of claws at the beginning of time.

source: Nature Communications