''Hercosestria'' is an extinct genus of

brachiopod Brachiopods (), phylum (biology), phylum Brachiopoda, are a phylum of animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear e ...

s from the Lower and Middle

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...

. They were important

reef A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic (non-living) processes such as deposition (geol ...

-forming organisms because of their conical shapes, attaching spines, and gregarious habits. It is related to ''Richthofenia''. Species of the genus have been found in Texas (''H. cribrosa'' and ''H. laevis'') and Guatemala (''H. notialis'').

References

File:HercosestriaSmallCluster040111.jpg, ''Hercosestria cribrosa'' Cooper & Grant 1969 ( Roadian,

Guadalupian The Guadalupian is the second and middle Series (stratigraphy), series/Epoch (geology), epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico an ...

, Middle

); Glass Mountains,

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

. File:HercosestriaPair040111.jpg, ''Hercosestria cribrosa'' Cooper & Grant 1969 (Roadian, Guadalupian, Middle Permian); Glass Mountains, Texas. Permian brachiopods Permian animals of North America Prehistoric brachiopod genera Productida {{brachiopod-stub