A Preliminary Taxonomic Study On The Potamanthidae From Mainland Of China (Insecta: Ephemeroptera)

The mayfly family Potamanthidae is a valid, distinct monophyletic clade of the superfamily Ephemeroidea (Insecta: Ephemeroptera). Up to now, 24 species have been described around the world, they are divided into 3 genera: Rhoenanthus (7 species), Anthopotamus (4 species), Potamanthus(13 species). Species in this family widely distribute in the Holarctic and Oriental regions, most of them in eastern and southeastern Asia. So far, 12 species in 2 genera have been reported from China. Unfortunately, the original description of them are relatively simple, a comprehensive research and review on them is needed, this thesis is a preliminary try.The first chapter of this thesis reviews research history and status quo on Potamanthidae of the world as well as in China. The previous work on this family of this country was relatively insufficient compared to the international level, especially on the biology and ecology. Concerned this issue, certain details of morphology, behavior and life history of potamanthid mayflies are reviewed in the second chapter. In the third and fourth chapters, specimens of the Potamanthidae collected from 16 provinces and municipalities of Chinese mainland are classified, identified and revised. As a result, 13 reported species belonging to 3 genera are recognized, confirmed, redescribed and figured in detail. Larvae of 4 species are described for the first time: Rhoenanthus magnificus Ulmer, Rhoenanthus hunanensis (You et Gui), Potamanthus (Potamanthodes ) kwangsiensis ( Hsu ), Potamanthus (Potamanthodes) macrophthalmus (You) ; Male adult of Potamanthus (Potamanthodes) longitibius Bae et McCafferty is firstly described. Rhoenanthus obscurus Navas. is firstly recorded from China. In addition, both imaginal and larval keys to genera and species are provided. With Scanning Electron Microscope, eggs of 12 species are observed and compared, digital photos of them are taken, they are: Rhoenanthus magnificus Ulmer, Rhoenanthus obscurus Navas, Rhoenanthus youi (Wu et You), Rhoenanthus hunanensis (You et Gui), Potamanthus (Patamanthus) huoshanensis (Wu), Potamanthus (Patamanthus) luteus oriens (L.), Potamanthus (Potamanthodes) formosus Eaton, Potamanthus (Potamanthodes) kwangsiensis (Hsu), Potamanthus (Potamanthodes) longitibius Bae et McCafferty, Potamanthus (Potamanthodes) macrophthalmus (You), Potamanthus (Potamanthodes) sangangensis (You), Potamanthus (Potamanthodes) yunnanensis (You et al). The pictures of them as well as some other mayflies reported previously indicate that egg characters of this family are almost uniform in structure pattern, but different from other family significantly. Further, eggs from mature nymphs and female adults of same species are identical in every tiny characters. So it is believed that the eggs of Potamanthidae can be useful for adult-nymph association, but should be qualified in species identification or phylogeny reconstruction because of their similar structure pattern.The specimens in present study are all preserved in 85% ethylalcohol and deposited in the College of Life Science, Nanjing Normal University.