The　Hongguleleng　Formation,　the　highest　and　most　important　Devonian　marine　carbonate　horizon　in　western　Junggar,　contains　an　endemic　shallow-water　Icriodus-Polygnathus　conodont　fauna　with　rare　palmatolepids　and　other　genera.　The　conodont　faunas　from　the　Bulongguoer　and　the　Wulankeshun　sections　are　similar,　with　high　abundance　(about　40%)　of　endemic　taxa　(13　taxa),　indicating　isolation　of　the　Junggar　Basin　during　early　Famennian.　Non-endemic　species　in　the　faunas　suggest　that　the　Lower　Member　of　the　Hongguleleng　Formation　is　assignable　to　the　Pa.　rhomboidea　Zone　to　the　Pa.　marginifera　marginifera　Zone　of　early　Famennian,　not　including　the　Frasnian-Famennian　boundary.　The　Upper　Member　may　be　of　late　Famennian-early　Tournaisian　in　age　on　the　basis　of　our　preliminary　faunal　analysis.　(c)　2021　Elsevier　B.V.　and　Nanjing　Institute　of　Geology　and　Palaeontology,　CAS.　All　rights　reserved.