Original paper

On the Pterotrigoniidae (Bivalvia, Trigoniida): their biogeography, evolution, classification and relationships

Cooper, Michael R.

Abstract

Current interpretation of the predominantly Cretaceous trigoniid bivalve subfamily Pterotrigoniinae is reviewed. 238 species are analyzed and three lineages identified which evolved in parallel throughout the Late Tithonian–Maastrichtian and provide the basis for subfamilial discrimination. Evolutionary relationships are discussed. The subfamily Linotrigoniinae is reduced to a tribe within Pterotrigoniinae, and the tribe Scabrotrigoniini is elevated to subfamily rank to include its Early Cretaceous progenitors. These two subfamilies are the basis of the family Pterotrigoniidae, whose origin is inferred to lie in Megatrigoniidae close to Anditrigonia. The new subfamily Oistotrigoniinae is introduced for the third lineage which evolved in parallel with Pterotrigoniidae. It is cryptogenic, although an origin in Myophorellinae has been suggested. Among Pterotrigoniinae 95 species are assigned to 12 genera, 6 of which are new. Scabrotrigoniinae comprise 88 species assigned to 13 genera, 8 of which are new. Within Oistotrigoniinae n. subfam. 41 species are assigned to 6 genera, 5 of which are new.

Keywords

palaeobiogeographynew taxaphylogenyclassificationtrigoniidabivalviapterotrigoniidaegeneric diagnoses