Elrathia fossil map
Where fossils of Elrathia have been found, shown on the Earth as it looked about 500 million years ago and on today’s map.
Dots are fossil collections recorded in the Paleobiology Database. The “then” view moves today’s fossil sites back to their positions 500 million years ago (the time slice nearest the median age of the fossils) using the Merdith et al. (2021) plate model; positions are approximate. Open on the timeline map →
| Group | Trilobites & sea scorpions |
|---|---|
| Lived | 509.7–486.85 million years ago (Stage 4 to Stage 10) |
| Periods | Cambrian |
| Family | Alokistocaridae |
| Named by | Walcott 1924 |
| Fossil records | 72 occurrences at 38 locations (PBDB) |
| Found in | United States, Canada, Greenland, Russian Federation, India, UK |
| Rock formations | Conasauga, Shallow Bay, Holm Dal, Wheeler, Burgess Shale, Upper Wheeler Shale |
About Elrathia
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.
"...trilobite occupied the exaerobic zone, at the boundary of anoxic and dysoxic bottom waters. E. kingii consistently occur in settings below the oxygen levels required by other contemporaneous epifaunal and infaunal benthic biota and may have derived energy from a food web that existed independently of phototrophic primary productivity. Although other fossil organisms are known to have preferred such environments, E. kingii is the earliest-known inhabitant of them, extending the documented range of the exaerobic ecological strategy into the Cambrian Period."
Text in “About” is quoted from the Wikipedia article Elrathia (revision 1322213313), licensed under CC BY-SA 4.0; introduction excerpted verbatim, formatting removed. Ages, family, authority and fossil records: Paleobiology Database, accessed 22 October 2026. Ages are those of the rock layers the fossils were found in.
