Description
Mississippian Pentremites Blastoid, reative to the Crinoid
Fossils from here are preserved in great detail. Because of the wide variety and number of these animals it is assumed they lived in dense communities,
Pentremites godoni Blastoid are animals related to modern day living starfish, sand dollars and sea urchins. But they also have modern relatives called crinoids.
Blastoids like their cousins cystoids are now exticnt because they could not adapt to changes in the environment. The Blastoids had many varied species but they shared body styles. The Mississippian Pentremites Blastoid consisted of a stem so it could anchor to the sea floor with a “holdfast” a theca. And it had arms to filter food from the water.
This Blastoid has exceptional detail. They had a structure called a holdfast because they needed a hard surface to attach to. It has been prepared using air abrasive tools.
During the Mississippian Period much of Illinois and Indiana were a warm and shallow tropical sea. Because of it’s location near the equator it was prone to violent storms. These storms were the reason we have such beautifully preserved fossils. Storms would was soft mud and sand into the shallow sea covering the animals so that they may be preserved. They are found in a soft and very brittle gray shale several feet below the surface topsoil.
Very nice LARGE Blastoid from Sulphur, Indiana.
The Mississippian Pentremites godoni Blastoid is an extinct echinoderm, related to modern day starfish. They were most common in the Mississippian Period. They are actually an animal attached to the bottom of the ocean by a stalk and holdfast. The had radiating arms which captured the food and brought it to the mouth. They were filter feeders and were quite common..
Specimen is just under 1 inch long and very inflated and robust. It comes in this handsome 4 1/2 inch by 5 1/2 inch leatherette glass topped collectors box.
