Fuxiana yangi g.n., sp.n. (Crustacea : Amphipoda), a "baikaloid" amphipod from the depths of Fuxian Hu, an ancient lake in the karst of Yunnan, China

The first search for endemic invertebrate fauna in the lesser-known ancient lake Fuxian Hu revealed a depths inhabiting amphipod. Fuxiana yangi g.n., sp.n. is a ca, 2-3 mm long, stout, gammaroidean amphipod inclined to develo p lateral protuberances. Taxonomically, the animal is a double enigma. (1) In spite of great polymorphism in its superficial trunk morphology - smooth , with a pair of horns, with pairs of lobes - the strong resemblance in app endage morphology speaks for the conspecificity of four specimens. (2) In s pite of the absence of the most striking character peg-shaped palmar spines - the shape of female gnathopods and some other characters speak for its p hylogenetic relation to the north Pacific anisogammarid stock rather than t o original (probably) Tethyan gammarid (s.str.) stock that reportedly gave rise to the rich amphipod flock of species and genera in Bajkalskoe Ozero ( Lake Baikal). Morphologically, Fuxiana is convergent with many phylogenetic ally unrelated stocks of ancient lake amphipods. Biologically, it is a K-st rategist with a small number of large eggs. It is accompanied by a very sca rce fauna in the lake's depths. A small endemic flock of anisogammarid spec ies inhabits the richer shallows.