Ostracods of the Late Devonian Frasnian/Famennian transition from Western Junggar, Xinjiang, NW China

Ostracods are described for the first time from the Late Devonian of western Junggar in Xinjiang, NW China. Fifty-two species belonging to 30 genera are recognized, and seven are new: Arcuaria hebukesarensis sp. nov., Bairdia shaerbuertiensis sp. nov., Cribroconcha honggulelengensis sp. nov., Microchelinella bulongourensis sp. nov., M. hoxtolgayensis sp. nov., Pribylites wulankeshunensis sp. nov. and P. junggarensis sp. nov. The ostracod fauna indicates a probable late Frasnian age for the lower member of the Hongguleleng Formation, and the Frasnian/Famennian boundary may exist in the basal part of the formation. The ostracod assemblages are referable to the Eifelian Mega-Assemblage, incorporating both the palaeocopid and smooth-podocopid associations. The fauna implies deposition in a nearshore-offshore environment during a transgression when the lower member of the Hongguleleng Formation was being deposited in western Junggar.