Palaeophonus

Palaeophonus (meaning "ancient killer") is the oldest known genus of scorpions.
Fossil records.
This genus is known in the fossil record from the Silurian to the Carboniferous (age range: 428.2 to 314.6 million years ago). Fossils have been found in Europe, the United States, and Canada.
Description.
"Palaeophonus" was virtually identical to modern scorpions. It grew to a lengths of . These animals did not have eyes and therefore they were blind.
Until a few decades ago, "Palaeophonus", similarly to many other scorpions of the Silurian, was thought to be one of the earliest animals to have conquered the land. In fact, a closer examination of the fossils has determined that these animals possess well-developed gills, very similar to those of contemporary eurypterids (sea scorpions).
Species.
Species within this genus include: