Ancient Spiders had Two Sets of Eyes
A new fossil study has found that ancient spiders were blessed with two sets of eyes. Researchers reached at the conclusion after studying a 305-million-year-old fossil of a harvestman.
They used the X-ray imaging techniques to find features of the unusually well-preserved fossil. The researchers from University of Manchester worked with colleagues at the American Museum of Natural History to conduct the study.
Harvestman had eight legs but they cannot be called spiders as they more closely associated with another arachnid, the scorpion, said Dr. Russell Garwood, a palaeontologist in the University of Manchester's School of Earth, Atmospheric and Environmental Sciences.
"Arachnids can have both median and lateral eyes, but modern harvestmen only possess a single set of median eyes and no lateral ones. These findings represent a significant leap in our understanding of the evolution of this group", added Dr. Garwood.
The fossil of the spider was uncovered in eastern France. The spider had both median eyes and lateral eyes on the side of the body.
Researchers do not have enough fossil evidence of terrestrial arthropods like harvestmen because their exoskeletons do not preserve well, said Prashant Sharma, a postdoctoral researcher in the Museum's Division of Invertebrate Zoology and one of the lead authors on the new study. Lack of fossil record is the biggest obstacle in the way of answering some fundamental questions in the evolutionary history of these organisms.
However, the last study has helped the researchers at the University of Manchester and American Museum of Natural History to gain significant insight into the evolutionary story of this diverse and highly successful group of arthropods. Experts say spiders exist on every continent except Antarctica. The findings of the study can be seen as a giant leap in the understanding of the evolution of arachnids group.