Fossil Of The Week Archives

Neospirifer

AGE: Pennsylvanian through Permian.
Neospirifer belongs to the Phylum Brachiopoda and is found widespread in North America. It is about 1 3/8 inches long and 2 1/8 inches wide. It's hinge width is equal or nearly equal to the maximum shell width. It has two valves both of which are convex. Inside the hinge small ridgelike teeth are present. Neospirifer and about eighteen other members of the family Spiriferidae became extinct at the end of the Permian Period which has caused great speculation as to the cause of their extinction. Some say that as much as 80% of all species became extinct at that time.

PENTREMITES

AGE: Missippian through Permian.
Pentremites belongs to the Phylum Echinodermata and Class Blastoidea. The blastoids were diverse and abundant in the Middle and late paleozoic. They were small, stemmed echinoderms. Pentremites, an invertabrate, was about 1 1/4" high and 1" wide. Pentremites while alive was held upright by it's stem, and used it's fragile arms for feeding. Pentremites is found widespread in North America and is common in the Upper Mississipian of the midwest.

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