It existed in the Silurian period and was one of the first arthropods to climb onto land about 437 million years ago (MYA). During the Silurian period competition for food was intense, this is the time when the oldest scorpions developed means to take advantage of the land. They learned to breathe with a primitive respiratory system, which are the same ones possessed by scorpions today.
Adapting from breathing in the water to and on land is similar to the modern horseshoe crab of today in the Quaternary period, in the Holocene era. Which is right where we are in the geologic time table right now. These old scorpions developed a respiratory structure that will allow them to move onto land, for a brief period.
The name given to it is "Parioscorpio venator", the genus is progenitor scorpion, and species nomenclature is a hunter. Officially named in the journal Scientific Reports as its official designation by the scientists who found it. "Parioscorpio venator" is the most archaic relation to arachnids or spiders, and flourish before their extinction. This was noted by Loren Babcock, author of the study, also a professor of earth sciences based at The Ohio State University.
Its discovery is made important by the transition of an aquatic arthropod, from living in the ancient Silurian sea and taking short jaunts by breathing on land. Before this feat, there was great competition in seeking prey that got easier by going onto dry land. Another significance is a model of how creatures shift from ocean to air-breathing, especially those vertebrate animals (backbone, spine) to follow. Without this step in scorpion evolution, it might have been different.
These fossils were first found in 1985, in Wisconsin and remained in obscurity for thirty years in the University of Wisconsin. By chance, Andrew Wendruff stumbled on the fossils and discovered it was one an old species of scorpion that was dated to 435 million years ago (MYA). One of the first animals to conquer dry land and become a terrestrial one, but it started with "Parioscorpio venator".
Several facts were established from the research done to study it.
A. Dating revealed that "Parioscorpio Venator" at the University of Wisconsin is older by 1 million and 3 million years. Far older than the other fossil in Scotland.
B. The exact era of these animals is the early Silurian and until the third period during the Paleozoic era. The estimated age of the fossils is 436.5 and 437.5 million years ago (MYA), as seen in the fossil record.
C. Ash beds are more accurate, or maybe microfossils used for more accurate dating. Carbon dating is not as accurate, which is the common misconception.D. Fossils of the ancient scorpion had the imprint of a primitive respiratory system, for air or land breathing. Another is the circulatory system which gave more clues to how it evolved.
D. It was small at 2.5 centimeters long which are as big as modern scorpions. It has the same insides as modern scorpions that are unchanged after millions of years.
F. Did these scorpions lived in water and left to hunt for prey, or resided on land to return to the sea periodically? So, far no definite answer yet from paleontologists is final.
Read: Fossil is the oldest-known scorpion