Oldest crustacean [Form]
Last updated: October 13, 2017 at 0:21 am
The horseshoe crab (Limulus polyphemus) has existed in its current form for the past 135 million years. Approximately 500,000 horseshoe crabs are harvested annually for their copper-rich blue blood, which uses hemocyanin instead of hemoglobin to carry oxygen. Amebocytes found in the blood is used to make Limulus amebocyte lysate, which is used to detect bacterial endotoxins in medical applications. Most horseshoe crabs survive the harvesting and subsequent release back into the sea. The ancestors of the horseshoe crab can be traced back to around 445 million years ago, or 200 million years before dinosaurs first appeared. They are thus considered living fossils.
Lenka Hurton (2003). Reducing post-bleeding mortality of horseshoe crabs (Limulus polyphemus) used in the biomedical industry (M.Sc. thesis). Virginia Polytechnic Institute and State University.
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Jeffrey Gallant is the Editor-in-Chief and Records Keeper of the Diving Almanac. He is also a contributing editor of DIVER Magazine, and the scientific director of the Greenland Shark and Elasmobranch Education and Research Group (GEERG). Jeffrey started diving in 1982.