1 Introduction The Mustelidae represent the largest living family of carnivorans and possesses an abundant fossil record in the early and middle Miocene of Europe and North America (e.g. Blainville 1842; Filhol 1872; Depéret 1892; Mayet 1908; Viret 1933, 1951; Helbing 1928, 1930, 1936; Dehm 1950; Ginsburg 1961, 1999, 2002; Roth 1989; Ginsburg and Morales 1992; Baskin 1998, 2005, 2017; Nagel et al., 2009; Peigné 2012; Valenciano et al., 2016, 2018). However, our understanding of Asiatic forms is more limited (Babbitt 1999, Peigné et al., 2006), despite Asia being located between the two continents. Early Miocene mustelid remains from Asia are poorly documented (Peigné et al., 2006); they include Mustela sp. and Proputorius from the Xiejia and Sihong Faunas in China (Qiu and Qiu 1995; Hunt 1996), the leptarctine Mustelidae Kinometaxia guangpui Wang et al., 2004 from Danghe, Tabenbuluk area of the northern Tibetan Plateau (Wang et al., 2004), an unidentified small mustelid from the DM16 locality in Damiao, Inner Mongilia (Zhang et al., 2011), and a P4 of another unidentified small mustelid from Kazakhstan (Kordikova et al., 2000: fig. 4e, f). The record of these forms in China during the middle Miocene is more complete. Mustelids from the Tunggur Formation (Fm.) in Inner Mongolia, of middle Miocene age, yield a better understanding of the family and the entire order (Qiu et al., 2013a and references herein). The local fauna of carnivores includes the inmigrant North American mustelids Leptarcus neimenguensis Zhai, 1964, and Sthenictis neimengguensis Tseng et al., 2009, as well as Melodon? sp. (Colbert 1939). In Damiao, the Tunggurian DM01 locality, several mustelids are present, but no details were published by Zhang et al. (2011). The middle First Record of Hoplictis (Carnivora, Mustelidae) in East Asia from the Miocene of the Ulungur River Area, Xinjiang, Northwest China Alberto VALENCIANO 1, 2, * , JIANGZUO Qigao 3, 4, 5, 6 , WANG Shiqi 3, 4, 7 , LI Chunxiao 3, 4, 5 , ZHANG Xiaoxiao 3, 4, 5, 8 and YE Je 3, 4 1 Research and Exhibitions Department, Iziko Museums of South Africa, PO Box 61, Cape Town 8000, South Africa 2 Department of Biological Sciences, University of Cape Town, Palaeobiological Research Group, Private Bag X3, Rhodes Gift 7701, Cape Town, South Africa 3 Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing100044, China 4 CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China 5 University of Chinese Academy of Sciences, Beijing 100049, China 6 Department of Paleontology, American Museum of Natural History, USA 7 CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing 100101, China 8 Tianjin Natural History Museum, Tianjin, 300201, China Abstract: The first unequivocal remains of medium to large-sized mustelids from the middle Miocene Halamagai and Kekemaideng formations have been found in the Ulungur River area, Xinjiang, northwestern China. These new fossils are referred to the hypercarnivorous mustelid Hoplictis Ginsburg, 1961 and denote the first record of the genus in East Asia. We define Hoplictis baihu n. sp., for the mustelid from Tieersihabahe (Halamagai Fm.), which represents the smallest species of the genus. This primitive form is closer to H. florancei and H. noueli than to H. anatolicus and later, larger and more derived Hoplictis spp., from Europe and North America. A large toothless mandible from Duolebulejin (Kekemaiden Fm.) is assigned to Hoplictis cf. helbingi, and it presumably might represent the first record of H. helbingi outside Western Europe. The systematic position of Hoplicitis in relation to Ischyrictis with which it is similar is clarified. The occurrence in East Asia of two species of Hoplictis greatly expands the known distribution and diversity of the genus, and supports a Palaearctic Neogene dispersal event of carnivorans between Europe and Asia during the late Shanwangian–early Tunggurian equivalent to MN5–6 in Europe, and indication of another dispersal event from Europe to North America, through Northwest China during the late Tunggurian, equivalent to MN7–8 in Europe. Key words: vertebrate paleontology, paleobiogeography, hypercarnivore, Hoplictis, Ischyrictis, Miocene, Xinjiang Citation: Valenciano et al., 2019. First Record of Hoplictis (Carnivora, Mustelidae) in East Asia from the Miocene of the Ulungur River Area, Xinjiang, Northwest China. Acta Geologica Sinica (English Edition), 93(2): 251–264. DOI: 10.1111/1755-6724.13820 * Corresponding author. E-mail: alb3rtovv@gmail.com Acta Geologica Sinica (English Edition), 2019, 93(2): 251–264 © 2019 Geological Society of China http://www.geojournals.cn/dzxbcn/ch/index.aspx; https://onlinelibrary.wiley.com/journal/17556724