Glyptorthis

Classification
Phylum: Brachiopoda
Class: Rhynchonellata
Order: Orthida
Family: Glyptorthidae
Genus: Glyptorthis Foerste, 1914
Cincinnatian species: Glyptorthis insculpta

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Geologic Range
Lower Ordovician (Llanvirn) – Middle Silurian (Wenlock)

Common Paleoecology
Glyptorthis is an extinct genus of stationary, epifaunal suspension feeders

Genus Characteristics

Moderately sized, biconvex shell with clear radial ornament
Many prominent concentric laminae, creates cross-hatched pattern
Hole under the pedicle opening is triangular
Shell shape ranges from subquadrate to subelliptical
Dorsal interarea small
Muscle scars on the ventral valve are heart-shaped, with the “open” part of the heart shape opening anteriorly.

Geographic Occurrences

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Wright (2012):

Shell of variable size, subquadrate to subelliptical in outline, unequally biconvex; ramnicostellate to fascicostellate, sometimes frilled; ornamentation concentric, strongly lamellose; rectimarginate to sulcate; delthryium open, triangular; ventral interarea short to long, orthocline to catacline; dorsal interarea small, orthocline to apsacline; subcordate ventral muscle scars, deflecting anteriorly, additional lateral deflection not uncommon; ventral adductor scars sometimes elevated on a raised platform; quadripartite dorsal muscle scars; thickened notothyrium; brachiophores divergent.

Treatise on Invertebrate Paleontology, Part H, Vol. 3 (2000):

Variable in size and in cardinal extremities, subequally biconvex, ramicostellate, strongly lamellose, ventral interarea of varying length , dorsal interarea short, curved; ventral muscle scars subcordate with adductors commonly raised on median callist extending forward as tongue of secondary shell; brachiophores divergent, rodlike

Fossils of Ohio (1996):

Medium-sized orthid brachiopod that has an unequally biconvex profile and an elliptical outline truncated by a straight hinge line. The width is greater than the length. The more inflated brachial valve has a sulcus. Numerous branching ribs radiate from the beaks of both valves. The intersection of radiating ribs and concentric growth lines results in a reticulate ornamentation on the exterior surface of the valves. The delthryium is open. The interior of the pedicle valve has a muscle scar consisting of two deep grooves, made by the diductor muscles; this muscle scar is separated by a ridged from the adductor muscle scars. Pallial markings are present beyond the muscle scar. Glyptorthis occurs in the Waynesville and basal Liberty Formations.

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G. insculpta