Potamothrix Vejdovsky & Mrazek , 1902

Cui, Yongde & Wang, Hongzhu, 2012, Three new species of Potamothrix (Oligochaeta, Naididae, Tubificinae) from Fuxian Lake, the deepest lake of Yunnan Province, Southwest China, ZooKeys 175, pp. 1-17 : 2-3

Potamothrix Vejdovsky & Mrazek, 1902

Type species.

Potamothrix moldaviensis Vejdovský and Mrázek, 1902

Emended diagnosis.

Hair chaetae present or absent, dorsal chaetae bifid and always pectinated, or only bifids. Ventral chaetae bifids. No coelomocytes. Vas deferens very short, entering atrium apically; atrium tubular, long. Prostate gland small, attached to proximal part of atrium by a short stalk, or no prostate gland. No ejaculatory duct. Penis with or without cuticular sheath. Spermatozeugmata present. Modified spermathecal chaetae present or absent.

Remarks.

The genus Potamothrix , established by Vejdovský and Mrázek (1902) for Potamothrix moldaviensis Vejdovský & Mrázek, 1902, was revised by Holmquist (1985) and Finogenova and Poddubnaja (1990). Altogether, 20 species were previously known and mainly distributed in the Holarctic region (Table 1) ( Brinkhurst and Jamieson 1971; Hrabě 1981; Brinkhurst and Wetzel 1984; Finogenova and Poddubnaja 1990; Šporka 1994; Milbrink 1999; Milbrink and Timm 2001). Through recent investigation of the plateau lakes, three species of Potamothrix ( Oligochaeta : Tubificinae ), Potamothrix rhytipeniatus Cui & Wang, 2012, Potamothrix aductus Cui & Wang, 2012 and Potamothrix scleropenis , have been found in the Fuxian Lake and Xingyun Lake of Yunnan Province, Southwest China ( Cui and Wang 2005). They are the lowest-latitude members of the genus hitherto known. Moreover, studies show that Potamothrix is unexpectedly species-rich in plateau lakes of Yunnan Province, especially in Fuxian Lake where five species were recorded ( Cui 2008; Cui and Wang 2005; Cui et al. 2008). In this paper, we will give the description of three new species, Potamothrix praeprostatus sp. n., Potamothrix paramoldaviensis sp. n. and Potamothrix parabedoti sp. n., from Fuxian Lake.