Horseshoe Crab (IMAGE) University of Wisconsin-Madison Caption University of Wisconsin-Madison postdoctoral researcher Jesús Ballesteros holds a small horseshoe crab. A study he led with Integrative Biology Professor Prashant Sharma used robust genetic analysis to demonstrate that horseshoe crabs are arachnids like spiders, scorpions and ticks. Credit Courtesy of Jesús Ballesteros Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.