Asaphus punctatus High-Eyestalked Russian Trilobite

Asaphus punctatus

Trilobites Order Asaphida, Family Asaphidae

Geological Time: Middle Ordovician, Asery Horizon

Size: (25.4 mm = 1 inch): 88 mm long by 50 mm wide on a 170 by 115 mm matrix

Fossil Site: Wolchow River Region, St Petersburg, Russia

Asaphus punctatusDescription: A well-inflated example of a high-eyestalked member of the Asaphidae, this is Asaphus punctatus. The region in which these trilobites lived was subject to dramatic changes in salinity and turbidity, and the trilobites were able to make rapid (geologically speaking) evolutionary adjustments. These adjustments were thought to be able to allow them to see both predator and prey more easily. Coming from an inland sea during the lower to middle Ordovician, the Russian trilobites from near Saint Petersburg, Russia participated in the Great Ordovician Radiation, which saw marine animal diversity increase three-fold more than the Cambrian Explosion. The Russian asaphid trilobites are a particularly interesting example of descent with modification.

Also see: Russian trilobites

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