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 |
