A Preliminary Research On Mayfly Diversity Of Hainan Island(Insecta:Ephemeroptera)

Fauna of Chinese Hainan Island is a hot topic of biodiversity research in the country.However,very few historical reports can be found on mayfly diversity of this island.Up to now,only 21 species in 9 families 17 genera were discovered,most of them were based on imaginal materials.In this thesis,more than 20,000 mayfly specimens collected from Hainan province are checked and classified,and the imagos are associated to nymphs as possible as we can using morphology and rearing.As a result,53 species belonging to 27 genera 11 families are recognized and identified.Among them,9 genera are recorded for the first time in Hainan.They are Baetiella,Acentrella,Labiobaetis,Nigrobaetis,Cloeon,Procloeon,Teloganodes,Isca,Epeorus.In addition,13 new species(Teloganopsis glossdlata sp.nov.;Eatonigenia zhangi sp.nov.,Choroterpes topicteti sp.nov.,Baetis strigosus sp.nov.,Acentrella rufomaculata.sp.nov.,Acentralla polymaculata sp.nov.,Nigrobaetis gracilus sp.nov.,Baetis rufomaculata sp.nov.,Baetis rubrolineatus sp.nov.,Cloeon maculosum sp.nov.,Procloeon lobulatum sp.nov.,Procloeon polymaculatum sp.nov.,Caenis aspina sp.nov.)are established.Meanwhile,19 species are recorded for new in Hainan.Furthermore,mayfly fauna of Hainan Island,the mainland and Taiwan province are compared on the updated data.Comparison result shows that the family,genus and species similarity between Hainan Province and Mainland are 50%,34.17%and 16.77%respectively.Given the fact that the area of Hainan Island is only 0.35%of the mainland,it has more mayfly complexity and diversity.Similar to Taiwan mayfly fauna,Hainan has no endemic family or genus here,but processes relatively more endemic species.This maybe results from that in geological history,both islands used to connect mainland,and was isolated geologically from neighboring lands in short time and distance.All specimens in this study are deposited in mayfly collection,Nanjing Normal University.