Rediscovering the Lys collection in the Muséum national d'Histoire naturelle (Paris, France): first report on Middle Permian ostracods from occidental Hindu Kush, Afghanistan

摘要

The micropalaeontology collections of the Muséum national d’Histoire naturelle in Paris (France) house the abundant and diverse collections gathered by Maurice Lys, geologist at the Institut Fran?ais du Pétrole from 1945 to 1971. Samples from the Middle Permian of the occidental Hindu Kush (central Afghanistan) collected and studied by Lys and his colleagues have been processed for ostracods study. Here, ostracods are for the first time reported from the Middle Permian (Roadian and Wordian) carbonate sequence of central Afghanistan, corresponding to 31 species distributed into 12 genera. Only small portions of the original samples have been treated, explaining the low abundance of the assemblage and the necessity to keep most of the species in open nomenclature. This discovery is nevertheless of major importance as it extends the palaeobiogeographic distribution of ostracods during the Middle Permian and further increases their palaeobiodiversity on the brink of the two extinction events at the end of the Palaeozoic. Palaeoenvironmental preferences of the recovered taxa seem to record an increase in the water depth from the east to the west over the studied area. The first analysis of ostracods provincialism during the Roadian is performed and identifies two clusters with strong similarity between South China Block and North American Platform and between central Afghanistan and Indochina Block.