Elrathia

thumb|right|250px|Elrathia kingii growth series with holaspids ranging from 16.2 mm to 39.8 mm in length

Elrathia is a genus of trilobite belonging to Ptychoparioidea known from the mid-Cambrian of Laurentia (North America). E. kingii is one of the most common trilobite fossils in the USA locally found in extremely high concentrations within the Wheeler Formation in the U.S. state of Utah. E. kingii has been considered the most recognizable trilobite. Commercial quarries extract E. kingii in prolific numbers, with just one commercial collector estimating 1.5 million specimens extracted in a 20-year career. 1950 specimens of Elrathia are known from the Greater Phyllopod bed, where they comprise 3.7% of the community.