Early Miocene bivalves from the Cape Melville Formation, King George Island, West Antarctica

Seven species of marine bivalves, including six new taxa, are described from the Cape early Miocene Melville Formation which crops out on the Melville Peninsula, King George Island, West Antarctica. The bivalve assemblage includes representatives of the families Nuculidae, Ennucula frigida sp. nov., E. musculosa sp. nov.; Malletidae, Neilo (Neilo) rongelii sp. nov.; Sareptidae, Yoldia peninsularis sp. nov.; Limopsidae, Limopsis psimolis sp. nov.; Hiatellidae, Panopea (Panopea) sp. cf. P. regularis; and Pholadomyoida (Periploma acuta sp. nov.). Species studied come from four sedimentary sections measured in the upper part of the unit. Detailed morphologic features of nuculoid and areoid species are exceptionally well preserved and allow for the first time reconstruction of muscle insertions as well as dentition patterns of Cenozoic taxa. Known geological distribution of the species is in agreement with the early Miocene age assigned to the Cape Melville Formation. The bivalve fauna from Cape Melville Formation is the best known from Antarctic Miocene rocks, a time of complex geologic, paleogeographic and paleoclimatic changes in the continent. The new fauna introduces new taxonomic and palaeogeographic data that bear oil the question of opening of sea gateways and distribution of Cenozoic biota around Antarctica.