Trilobite Diversity
Abrupt appearance of trilobite orders in the fossil record
Introduction
Many groups of organisms appear abruptly in the fossil record, often with a high diversity of families. The different groups are not linked by transitional forms, but are separated by morphological gaps.
Nearly all phyla of marine animals known today are first recorded in Cambrian sediments, along with several extinct types. Trilobites are the most ubiquitous and varied organisms of this "Cambrian Explosion." Each continent has a diverse group of trilobites in Cambrian and Ordovician sediments, with no evidence of evolutionary ancestry.
Trilobites Around the Globe
Below, you will find a diverse selection of trilobites from GRI's fossil collection. Browse by scrolling the list of fossils on the left, or by location using the map on the right. Some entries have a "See in 3D" link, where you can inspect the fossil from every angle.
Note: The location of pins is approximate.
Ptychopariida, Elrathia kingii
Ptychopariida, Elrathia kingii. Click to expand.
Wheeler Shale, House Range, Millard County, Utah; Middle Cambrian GRI #656
Asaphida, Norinia
Asaphida, Norinia. Click to expand.
Yinchufu Series, Yongshun, Hunan Province, China; Lower Ordovician GRI #667
Corynexochida, Paraszechuanella
Corynexochida, Paraszechuanella. Click to expand.
Yinchufu Series, Yongshun, Hunan Province, China; Lower Ordovician GRI #668
Ptychopariida, Yunnanocephalus yunnanensis
Ptychopariida, Yunnanocephalus yunnanensis. Click to expand.
Chengjiang County, Yunnan Province, China; Lower Cambrian GRI #671
Redlichiida, Eoredlichia intermedia
Redlichiida, Eoredlichia intermedia. Click to expand.
Chengjiang County, Yunnan Province, China; Cambrian GRI #672
Olenida, Parabolina
Olenida, Parabolina. Click to expand.
Eastern Cordillera Fm, near Salta, NW Argentina; Lower Ordovician GRI #673
Trinucleida, cf Lonchodomas
Trinucleida, cf Lonchodomas. Click to expand.
Northwestern Argentina; Lower Ordovician GRI #674
Ptychopariida, Estaingia (Hsuaspis)
Ptychopariida, Estaingia (Hsuaspis). Click to expand.
Emu Bay Shale, Kangaroo Island, Australia; Lower Cambrian GRI #677
Redlichiida, Emuella
Redlichiida, Emuella. Click to expand.
White Point Conglomerate, Upper Section, West side of Cape D'Estaing, Kangarroo Island, South Australia; Lower Cambrian GRI #678
Phacopida, Foulonia sp.
Phacopida, Foulonia sp.. Click to expand.
Morocco; Ordovician GRI #684
Harpetida, cf Harpides
Harpetida, cf Harpides. Click to expand.
Fezouata Formation, Zagora Region, Morocco; Lower Ordovician GRI #681
Corynexochida, Eastonillaenus goonumblaensis
Corynexochida, Eastonillaenus goonumblaensis. Click to expand.
Gunningbland Fm, Gunningbland Tip,j Gunningbland, NSW, Australia; Upper Ordovician GRI #676
Lichiida, cf Parvilichas
Lichiida, cf Parvilichas. Click to expand.
Fezouatta Fm, Zagora Region, Morocco; Lower Ordovician GRI #682
Odontopleurida, Selenopeltis sp.
Odontopleurida, Selenopeltis sp.. Click to expand.
Fezouatta Fm, Zagora Region, Morocco; Lower Ordovician GRI #683
Phacopida, Pliomera fischeri
Phacopida, Pliomera fischeri. Click to expand.
Russia; Middle Ordovician GRI #661
Agnostida, Megagnostus glandiformis
Agnostida, Megagnostus glandiformis. Click to expand.
Upper Fauna, Christmas Hills, Smithton, Tasmania, Australia; Lower Middle Cambrian GRI #675
Ptychopariida, Hamatolenus vincenti
Ptychopariida, Hamatolenus vincenti. Click to expand.
Jbel Wawrmast Fm, Tinjdad, Morocco; Middle Cambrian GRI #685
Ptychopariida, Elrathia kingii
Ptychopariida, Elrathia kingii. Click to expand.
Wheeler Shale, House Range, Millard County, Utah; Middle Cambrian
Ptychopariida, Asaphiscus wheeleri
Ptychopariida, Asaphiscus wheeleri. Click to expand.
Wheeler Shale, Utah; Middle Cambrian GRI #837
Asaphida, Glyphaspis capella
Asaphida, Glyphaspis capella. Click to expand.
Wolsey Shale, Gallatin Coounty, Montana; Middle Cambrian
Redlichiida, Nevadia
Redlichiida, Nevadia. Click to expand.
Pioche Shale, E-SE Nevada; Lower Cambrian
Agnostida, Ptychagnostus atavus
Agnostida, Ptychagnostus atavus. Click to expand.
Wheeler Shale, House Range, Millard County, Utah; Middle Cambrian
Redlichiida, Paradoxides gracilis
Redlichiida, Paradoxides gracilis. Click to expand.
Jince Formation, Bohemia, Western Czech Republic; Middle Cambrian.
Proetida, Paraproetus girvanensis
Proetida, Paraproetus girvanensis. Click to expand.
Drummock Group, Threave Glen, Aryshire, Scotland; Upper Ordovician
Ptychopariida, Ellipsocephalus hoffi
Ptychopariida, Ellipsocephalus hoffi. Click to expand.
Jince Fm, Bohemia, western Czech Republic; Middle Cambrian
Corynexochida, Illaenus excellens
Corynexochida, Illaenus excellens. Click to expand.
Vilpovitsy Quarry, St Petersburg region, Russia; Middle Ordovician
Corynexochida, Bathyuriscus haydeni
Corynexochida, Bathyuriscus haydeni. Click to expand.
Marjum Fm, House Range, Millard County, Utah; Middle Cambrian
Asaphida, Parkesolithus gradyi
Asaphida, Parkesolithus gradyi. Click to expand.
Gunningbland Shale, Gunningbland, NSW, Australia; Upper Ordovician
Asaphida, Ampyx
Asaphida, Ampyx. Click to expand.
Zagora Region, Morocco; Lower Ordovician
Redlichiida, Daguinaspis ambrogii
Redlichiida, Daguinaspis ambrogii. Click to expand.
Issendalen Stage, Daguinaspis Zone, Anti-Atlas Mts, Tazemourt, Taroudant Province, western Morocco; Lower Cambrian
Ptychopariida, Elrathia kingii
Wheeler Shale, House Range, Millard County, Utah; Middle Cambrian GRI #656
Asaphida, Norinia
Yinchufu Series, Yongshun, Hunan Province, China; Lower Ordovician GRI #667
Corynexochida, Paraszechuanella
Yinchufu Series, Yongshun, Hunan Province, China; Lower Ordovician GRI #668
Ptychopariida, Yunnanocephalus yunnanensis
Chengjiang County, Yunnan Province, China; Lower Cambrian GRI #671
Redlichiida, Eoredlichia intermedia
Chengjiang County, Yunnan Province, China; Cambrian GRI #672
Olenida, Parabolina
Eastern Cordillera Fm, near Salta, NW Argentina; Lower Ordovician GRI #673
Ptychopariida, Estaingia (Hsuaspis)
Emu Bay Shale, Kangaroo Island, Australia; Lower Cambrian GRI #677
Redlichiida, Emuella
White Point Conglomerate, Upper Section, West side of Cape D'Estaing, Kangarroo Island, South Australia; Lower Cambrian GRI #678
Harpetida, cf Harpides
Fezouata Formation, Zagora Region, Morocco; Lower Ordovician GRI #681
Corynexochida, Eastonillaenus goonumblaensis
Gunningbland Fm, Gunningbland Tip,j Gunningbland, NSW, Australia; Upper Ordovician GRI #676
Odontopleurida, Selenopeltis sp.
Fezouatta Fm, Zagora Region, Morocco; Lower Ordovician GRI #683
Agnostida, Megagnostus glandiformis
Upper Fauna, Christmas Hills, Smithton, Tasmania, Australia; Lower Middle Cambrian GRI #675
Ptychopariida, Hamatolenus vincenti
Jbel Wawrmast Fm, Tinjdad, Morocco; Middle Cambrian GRI #685
Ptychopariida, Elrathia kingii
Wheeler Shale, House Range, Millard County, Utah; Middle Cambrian
Asaphida, Glyphaspis capella
Wolsey Shale, Gallatin Coounty, Montana; Middle Cambrian
Redlichiida, Nevadia
Pioche Shale, E-SE Nevada; Lower Cambrian
Agnostida, Ptychagnostus atavus
Wheeler Shale, House Range, Millard County, Utah; Middle Cambrian
Redlichiida, Paradoxides gracilis
Jince Formation, Bohemia, Western Czech Republic; Middle Cambrian.
Proetida, Paraproetus girvanensis
Drummock Group, Threave Glen, Aryshire, Scotland; Upper Ordovician
Ptychopariida, Ellipsocephalus hoffi
Jince Fm, Bohemia, western Czech Republic; Middle Cambrian
Corynexochida, Illaenus excellens
Vilpovitsy Quarry, St Petersburg region, Russia; Middle Ordovician
Corynexochida, Bathyuriscus haydeni
Marjum Fm, House Range, Millard County, Utah; Middle Cambrian
Asaphida, Parkesolithus gradyi
Gunningbland Shale, Gunningbland, NSW, Australia; Upper Ordovician
Asaphida, Ampyx
Zagora Region, Morocco; Lower Ordovician
Redlichiida, Daguinaspis ambrogii
Issendalen Stage, Daguinaspis Zone, Anti-Atlas Mts, Tazemourt, Taroudant Province, western Morocco; Lower Cambrian
Geologic Column
Trilobites have been classified in twelve orders. Eleven of these appear in Cambrian rocks. Trilobite diversity appears abruptly, not as evolutionary theory predicts. In evolution, one would expect to find a record of gradual, incremental changes in transitional forms between separate groups. However, as evidenced by the Cambrian Explosion of trilobites, the larger differences exist from the beginning of the fossil record.
The Geologic Column
Learn More
The significance and complexity of trilobites:
The GRI documentary: Evidences II: The Tale of a Trilobite
Dr. James Gibson's commentary on a recent significant study of trilobites
