Asaphus raniceps

Trilobites Order Asaphida Suborder Asaphina, Superfamily Asaphoidea, Family Asaphidae
Geologic Age: Lower Ordovician
Trilobite is 75 mm long
Kunda Level deposits of the Wolchow River region near Saint Petersburg, Russia
Remark: The area where Russian trilobites lived in the Ordovician experienced dramatic changes in salinity and turbidity, exerting significant selective pressure. Their fossil record is one of rapid adaptation, especially allowing them to see both predator and prey more easily. Asaphus raniceps was a stem trilobite taxon that ultimately led to Asapahus ornatus, the last survivor of the genus. Note the significant effacement of the entire exoskeleton.

Also see: Russian Trilobites Evolution in Russian Ordovician Asaphids








Asaphus raniceps Asaphida Trilobite

Asaphus raniceps Russian Asaphid Trilobite

The Cephalon is effaced and smooth:

Asaphus Trilobite Evolution

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