Phylum: Mollusca
Class: Bivalvia
Order: Pholadomyoida
Family: Grammysiidae (Miller, 1877)
Cincinnatian Genera: Cuneamya

Geologic Range
?Early Ordovician, Middle Ordovician – Late Permian

Common Paleoecology
Grammysiidae is an extinct family of facultative mobile infaunal suspension feeders

Description of the Family

  • Oval to elongate forms
  • Characterized by smooth surface or concentric ornamentation
  • Radial ribs with elongate ligaments
  • Lunule and escutcheon commonly present
  • Posterior umbonal ridge well defined in majority of the genera
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Treatise on Invertebrate Paleontology, Part N, Mollusca 6(2 of 3) (1969):

  • Oval to elongate forms characterized by smooth surface or concentric ornamentation; radial ribs commonly subordinate; ligament elongate; nymphs obscure; lunule and escutcheon commonly present; posterior umbonal ridge well defined in majority of genera; pallial line entire; hinge edentulous. A poorly known, probably heterogeneous grouping of convenience.

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