eurypyx Agnostid Trilobites Death Assemblage
Order Agnostida, Family Diplagnostidae
Time: Middle Cambrian
Size: 2 -
Site: House Range, Wheeler Shale, Millard County, Utah
Agnostida comprises trilobites that appeared in the Lower Cambrian,
became widespread and then declined to become rare in the Ordovician
prior to their complete extinction by the end of the Ordovician.
They are so unusual that some experts have suggested that one of
the two suborders, Agnostina, should not even be included in Class
Trilobita. Most are blind, and have a pygidium equal in size to
the cephalon (ispopygous), making it hard to tell which end was
which! This is one of the more rare spiny types.
members of the Agnostida are mostly thought to have been planktonic
fossil pictures to enlarge