A new species of Brotia from Yunnan, China (Caenogastropoda, Pachychilidae) Frank Kæhler * ,1 , Du Li-Na 2 and Yang Jun-Xing §, 2 1 Australian Museum, 6 College Street, Sydney, NSW 2010, Australia 2 State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China § Correspondence to be sent to Yang Jun-Xing, e-mail: yangjx@mail.kiz.ac.cn Introduction With dramatic variations in climate and topography, the mountains of the south-western Chinese province Yun- nan support a wide array of habitats that harbour a highly diverse and endemic biota. However, due to the effects of an expanding human population, the increas- ing exploitation of resources and the pollution and de- struction of natural habitats, Yunnan’s biodiversity is faced with considerable threats (Yang et al. 2004). The impacts on freshwater habitats are illustrated by the pollution and overharvesting of many lakes of the Yun- nan Plateau. As a result of these disturbances, a consid- erable proportion of the endemic freshwater fauna has become either threatened or even extinct (Zhang et al. 1997; Cui et al. 2008). For example, a recent survey of freshwater molluscs in thirteen lakes of the Yunnan- Guizhou Plateau has revealed that although once widely distributed and represented by a number of endemic species, the viviparid snail Margarya Nevill, 1877 be- came extinct in most of these lakes. Two species have hardly survived in two larger lakes, where they cur- rently are at the brink of extinction (Shu et al. 2010). The mountains of the Yunnan also feed the most spe- cies-rich river systems in Asia. Major rivers that tra- verse or originate in this region include the Jingsha- jiang, Yalongjiang, Nujiang, Daduhe, Minjiang, the Yangtze and the Mekong Rivers (Conservation Interna- tional & McGinley 2008). However, in particular the invertebrate fauna of these rivers is poorly known. Pa- chychilid gastropods may just be taken as an example to illustrate the paucity of our knowledge of this fauna, which is another impediment for the implementation of conservation strategies. This group of freshwater gastro- pods is represented in mainland Southeast Asia by two widely distributed genera, Brotia H. Adams, 1866 and Sulcospira Troschel, 1858 (Kæhler & Dames 2009). Species of both groups are thought to also occur in southern to south-western China (in particular in the Provinces Yunnan, Guizhou, Guangxi, Guangdong, and Hainan). However, available reports are scarce, impre- cise, often only historical, and frequently flawed by re- ference to incorrect taxonomic names. Sulcospira is known to occur in Laos (Kæhler, unpubl. data), Vietnam (Kæhler et al. 2009) and Hong Kong (Dudgeon 1982). However, the full extent of its distribution in southern China, particularly in the area between Hong Kong and northern Vietnam, is unknown. A number of nominal taxa with currently unclear taxonomic status are also attributed to this pachychilid group (Kæhler & Glau- # 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Received 30 April 2010 Accepted 11 May 2010 Published 24 September 2010 Key Words Southeast Asia Freshwater Mollusca Taxonomy Abstract A new species of pachychilid freshwater gastropods, Brotia yunnanensis n. sp., is de- scribed from the Mengnong River in the Lancang (= Mekong) River drainage of Yun- nan, Southern China. This species is characterised by the unique combination of a comparatively small, conical shell with a sculpture consisting of densely arranged but weakly developed axial ribs that support two spiral rows of weak nodules, and a round, multispiral operculum. Brotia yunnanensis n. sp. is the first confirmed report of this genus from China. It is anticipated that further species are to be found in this region, which currently remain unknown. Zoosyst. Evol. 86 (2) 2010, 295 – 300 / DOI 10.1002/zoos.201000012 * Corresponding author, e-mail: frank.koehler@austmus.gov.au