Overview
- The peer-reviewed Nature paper, published Wednesday, names Megachelicerax cousteaui and confirms preserved pincer-like mouthparts called chelicerae.
- The 8-centimeter animal shows a head shield and nine body segments with six pairs of head limbs for feeding and sensing plus plate-like structures that resemble book gills.
- The fossil comes from Utah’s Middle Cambrian Wheeler Formation and was collected in 1981 by Lloyd Gunther before curation at the University of Kansas museum.
- The discovery moves the chelicerate fossil record back about 20 million years and indicates key traits formed before head limbs changed into spider-like legs.
- Analyses place the species as an early branch linking Cambrian forms to later horseshoe crab-like lineages, highlighting how museum collections can reshape the timeline of a group that now includes more than 120,000 species.