Zhongshan City,located in the delta of Pearl River in Guangdong Province,covers an area of 1 800 km2,with various water bodies including rivers,streams,reservoirs and ponds.Previously,the fauna of freshwater Oligochaeta in this area has not been studied.Based on the surveys in 16 water bodies conducted in June and December,2005,a total of 31 species(including 19 species new to Guangdong Province)of aquatic oligochaetes belonging to 16 genera and 4 families are recorded from Zhongshan City.Faunistic analysis has shown that Zhongshan area has more thermophilus species than northern areas of China.Aulophorus flabelliger of Naididae is recorded from China for the first time,and described as follows.Aulophorus flabelliger Stephenson,1931(Fig.2)Material:IHB GD2005006a-b,two whole-mounted specimens;IHB GD2005006c-d,two glycerine-mounted specimens;GD2005006e,one specimen in 10% formalin;all from plant roots in Beitaiyong stream(22°26'29.7″N,113°22'34.9″E)of Zhongshan in June,2005.The specimens are deposited in the Institute of Hydrobiology(IHB),Chinese Academy of Sciences,in Wuhan,China.,Description:Five complete preserved specimens about 3 mm long,0.18 mm wide,21-26 segments.Body was transparent.No eyes.Dorsal chaetae from VI onwards.1 hair per bundle,72-76 μm long.1 palmate needle per bundle,44-48 μm long,2.7-2.9 μm thick,with nodulus distal;teeth strongly diverging,maximally 12 μm wide,distal one 12 μm long and proximal 10 μm long,with web and 20-25 intermediate teeth.Ventral bifids of Ⅱ-Ⅴ 3-5 per bundle,90-102 μm long,2.4-2.5 μm thick,longer and thinner than the rest,with nodulus proximal;distal tooth 5.0 μm long and proximal 2.9 μm long.Those following 3-4 per bundle,44-52 μm long,1.9 μm thick,with nodulus distal;distal tooth much shorter and thinner than proximal(1.5 μm∶2.9 μm in length,0.7 μm∶2.1 μm in base thickness).Branchial fossa with 3 pairs of long,cylindrical gills,and a pair of finger-like parallel palps.Portable tube about 4 mm long,0.24 mm wide,delicate and transparent.Remarks:This tropical species was originally described from Kenya^[18],and subsequently reported from Somalia^[14],Australia^[12],India^[15] and southern USA^[13].Our material conforms to the previous descriptions(op.cit.)in most aspects,but needles are different to some extent(Table 2).Under an oil immersion objective,needles of our specimens were found to have numerous intermediate teeth,which have not been mentioned before.The forms of specimens from Somalia and India were reported to have web indentations near distal teeth of needles,and those from Kenya,Australia and USA near proximal teeth.The authors are of the opinion that the difference in needles is a matter of observation,for the numerous teeth are rather difficult to be distinguished from the web;under a 40× objective,the needles of Zhongshan worms were similar to the published drawings.In addition,hairs and needles of the present specimens are somewhat shorter than those in the previous descriptions.Distribution and habitat:Zhongshan of South China(new record),India,East Africa(Kenya,Somalia),Australia,and USA(Louisiana);all tropical and subtropical regions(31°N-29°S).Decomposing roots of water-plant in ponds and streams.