A new genus of Pergamidiidae (Bivalvia) from the Late Triassic of the Changtai-Gacun area, eastern Qinghai-Xizang Plateau, China

The new epi-byssate bivalve Parapergamidia changtaiensis gen. et sp. nov. of the family Pergamidiidae occurs in the Upper Triassic (? Late Carnian–Early Norian) Tumugou Formation of the Changtai-Gacun area, eastern Qinghai-Xizang Plateau, China. During the Late Triassic, this area was an intra-arc rift of the Yidun Island Arc along the eastern margin of the Tethyan seaway. The new taxon has a big byssal gape, prominent byssal retractor muscle scars, and anteriorly oblique and posteriorly to posteroventrally elongated shape. The thin shell is distinctly longer than high.