''Hercosestria'' is an extinct genus of

brachiopod Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan 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 end, w ...

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 251.9 Mya. It is the last ...

. 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 processes— deposition of sand, wave erosion planing down rock o ...

-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 In the geologic timescale, the Roadian is an age or stage of the Permian. It is the earliest or lower of three subdivisions of the Guadalupian Epoch or Series. The Roadian lasted between and million years ago (Ma). It was preceded by the ...

Guadalupian The Guadalupian is the second and middle series/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 and Texas, and dates between 272.95 ± ...

, Middle

); Glass Mountains,

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

. 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