& cystoid
Geological Time: Middle Ordovician
Size: 48 mm
Fossil Site: Russian trilobites Asery level, St. Petersburg region, Wolchow river, Russia
Asaphus kotlukovi represents an evolutionary branch beginning and ending in the Middle Ordovician. It begins a morphological sequence of increasing eye-stalk size, and was progenitor of Asaphus punctatus, and later Asaphus intermedius that had increasingly higher eye stalks.
Also see: Russian Trilobites Gallery Russian Asaphidae Evolution Sequence
Click trilobite pictures to enlarge