Pterotrigonia is an extinct genus of saltwater clams, marine bivalve molluscs in the family Megatrigoniidae. This genus is known in the fossil record from the Jurassic period Tithonian age to the Cretaceous period Maastrichtian age. Species in this genus were facultatively mobile infaunal suspension feeders. The type species of the genus is Pterotrigonia cristata.

Pterotrigonia thoracica was selected as the state fossil of Tennessee in 1998.

Scabrotrigonia is a subgenus of Pterotrigonia.

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