Adamussium jonkersi sp. nov. is described from the Late Oligocene Destruction Bay Formation, Wrona Buttress area, King George Island (South Shetlands), West Antarctica. The unit, characterized by volcanic sandstone, is a shallow marine succession deposited in a moderate- to high-energy environment. The thin-shelled pectinids, collected from the lower part of the unit, are preserved mostly as complete valves. Shell thickness, sculpture pattern and umbonal angle suggest a free-living, inactive swimming life habit.

The well-known Pleuronectia badensis Fontannes, 1882 (currently classified as Cristatopecten cristatus badense) is declared as a n omen protectum against the older synonym Pecten burdigalensis var. polonica Pusch, 1837 considered a nomen oblitum. It ranges from the early to the late Miocene (Burdigalian–Messinian) of the NE Atlantic and Mediterranean. In the Central Paratethys it appeared in the early Miocene (Karpatian, correlating with the latest Burdigalian) and became extinct in the middle Miocene (Late Badenian, correlating with the early Serravallian). In Poland – the northernmost part of Central Paratethys – the occurrence of this taxon is limited to the late Early Badenian (late Langhian).