Trilobites Button for link to Chinese version of this page

The Trilobites. The trilobites thrived in our planet’s seas for many million years. They first show up in the fossil record about 540 million years ago, right in the earliest era of the Cambrian when the Cambrian explosion of life diversity began. They very slowly and gradually died out from 300-240 million years ago, and disappear from the fossil record after the terrible die-off at the Permian-Triassic boundary (245-251 million years ago). They were arthropods, but whether they were more closely related to crustaceans, cheliceramorpha (horseshoe crabs and sea scorpions and arachnids), or pycnogonida (sea spiders) isn't entirely understood.

Dalmanites limulurus
Middle Silurian (420 MYA) from Rochester, New York
A "classic" trilobite, with its tail-spine and prominent eyes
making it look like a horese-shoe crab.
(caption at Wyoming Dinosaur Center)

Possibly a species of Chotecops
Early Devonian (400 MYA) from Germany
Chotecops is genus of trilobite with many species. It lived
at the height of trilobite diversity.
(caption at Wyoming Dinosaur Center)

Elrathia kingii
Cambrian (530-510 MYA)
From Millard County, Utah.
One of the most common trilobites in the world, Elrathia
is an index fossil used to correlate rocks worldwide.
(caption at Wyoming Dinosaur Center)

Links about the Trilobites:
  1. The Trilobites website has great pages about trilobite life (Sam M. Gon III).
  2. An Australian Museum Online site about the trilobites.
  3. The Fossil Museum has interesting pages about trilobites.
  4. The Peronopsis interstricta (or some other Agnostida?) trilobite fossils shown on this page were found near Delta, Utah close to the private U-Dig fossil quarry, a commercial outfit that gives people a chance to find trilobite fossils.
  5. Many trilobite fans have created websites full of photographs of trilobite fossils. This is one of the better ones, by Mark Bourrie.
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This work by Eric & Chun-Chih Hadley-Ives is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License .