Trilobite Fossils Reveal Extra Legs in Upstate New York

• A study by the American Museum of Natural History and Nanjing University in China reveals an additional set of legs underneath a trilobite species’ head.
• Trilobites, extinct arthropods, have multiple segments, with the head region consisting of fused segments.
• The study reveals a mismatch between the count of segments in the trilobite head and the count of preserved antennae and legs.
• The study examined newly recovered Triarthrus eatoni fossils from upstate New York, which showed an additional, previously undescribed leg underneath the head.
• Comparing the trilobite head with another species, the exceptionally preserved Olenoides serratus, the researchers propose a model for appendage attachment to the head.