5.4" Plate of Green Brachiopod (Orthotetes?) Fossils - Illinois

This is a unique fossil brachiopod cluster that was collected from the Burlington Limestone of Plainville, Illinois. The fossils are believed to be brachiopods of the genus Orthotetes sp., however this classification is purely by the resemblance of this fossil to other Orthotetes brachiopod fossils and is not a conclusive genus identification.

It comes with an acrylic display stand.

Brachiopods are members of the phylum Brachiopoda. They are clam-like with wide shells composed of two halves called valves. They are filter feeders that live fixed to rocks or on the seafloor. Brachiopods first appeared in the early Cambrian as simple forms with non-articulating shells. Their diversity peaked during the Devonian, and there are currently 12,000 described fossil species of Brachiopoda from 5,000 genera. Most species of brachiopod died out during the Permian-Triassic Extinction but about 450 species still live today. They live in cold marine environments like polar seas or continental shelves and slopes. The largest fossil Brachiopod found is 7.9 inches (200 mm), but most are 2-4 inches (3-8 cm). Living Brachiopods also fall into this range.

Brachiopods are more closely related to Bryozoans than Mollusks. The easiest differences to identify are in the shells of clams, part of the mollusk family, and Brachiopods. Mollusk shells are divided into left and right while brachiopod shells are divided top (dorsal) and bottom (ventral). Mollusk shells are usually equal on the right and left. In brachiopods, the bottom shell is larger than the top. The other big difference is in how they feed: both are filter feeders, but mollusks extend their filter into the water and pull food into their shells. Brachiopods have internal feeding structures: water is drawn into the shell where the food is filtered out before expelling it out.
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DETAILS
SPECIES
Orthotetes sp.?
LOCATION
Plainville, Illinois
FORMATION
Burlington Limestone
SIZE
1.85" Largest brachiopod on 5.4 x 4.1" rock
CATEGORY
ITEM
#136517
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