LUNULACARDIIDS FROM THE DEVONIAN PELAGIC FACIES

Despite their abundance and their global distribution, the Late Devonian pelagic bivalves have not been in the focus of the scientific interest for almost century. These bivalves are part of a low diverse, but characteristic deeper water fauna, and are common in condensed limestones, nodular limestones, and in fine siliciclastics including black shales. The ongoing research concerning these Late Devonian pelagic taxa comprises, besides a basic systematic revision, a first time compilation of information on morphology, stratigraphic range, and paleobiology. The lunulacardiids are used to give an example for the problems as well as the newly gathered results on the Late Devonian bivalve from the pelagic facies. The lunulacardiids comprising genera such as e.g., Lunulacardium and Chaenocardiola are one of the more commonly used taxa of the facies. But the systematic problems with this group start already with its name. Although the author of the genus named it Lunulacardium, all subsequent authors used the term Lunulicardium. Another issue is the orientation of the valves and its implication for a possible reconstruction of the soft body. Closely related to their bauplan are their assumed life habits, which particularly includes their ability to survive major extinction event such as e.g.,, the Kellwasser Events on the Frasnian / Famennian boundary or the Hangenberg Event on the Devonian/Carboniferous boundary.