Species Diversity,Phylogeny And Biogeography Of Diaptomidae(Copepoda: Calanoida)in China

This research investigated in a comprehensive and systematic way the species diversity and distribution characteristics of the Diaptomidae in China,based on literature data and our own data from field work during 2012-2016.We present an updated checklist of the Diaptomidae in China.A total of 19 genera and 57 species were recorded.Neutrodiaptormus has the highest species richness(10 species),followed by Arctodiaptormus(9 species).The taxonomic status of sixteen species was revised,one wrongly attributed genus,Argyrodiaptomus,was corrected to Sinodiaptomus(2014),and one recently described cave-dwelling genus,Karstodiaptomus(2017)added.First records include Arctodiaptomus parvispineus(2013)and Karstodiaptomus sheni(2017)in China.One latin name in Shen&Sung's book(1979)is corrected Eudiaptomus graciloides.Three types of distribution patterns were summarized(Pattern 1-3):cold water&high altitude species,warm water species,and widespread species.The species richness(26 species)is higher in the Oriental region than in the Palaearctic zone(23 species).According to an Redundancy analysis(RDA),the latitude and altitude variables in China explained 5%of the distribution variation of diaptomidae and there is a clear difference in spatial distribution of diaptomidae between north and south ChinaSecondly,we moved Allodiaptomus rarus into Mongolodiaptomus by combination of taxonomic morphologies and DNA genetic divergence analysis.We also found that Neodiaptomus blachei and Vietodiaptomus hatinhensis are not from two separate genera,but the two are sister species.The phylogenetic tree by ITS and COI genes also revealed that hybridization happend among Neodiaptomus schmackeri,Phyllodiaptomus tunguidus,Sinodiaptomus ferus and Sinodiaptomus cavernicolax,especially in the southern Pearl River basin.Thirdly,we analysed the population genetic structure of N.schmackeri and P.tunguidus with cytochrome b gene sequences.In total 61 haplotypes were found in 15 subpopulations of N.schmackeri.Geographic partition was evident from its haplotype network analysis:Clade 1 was limited in north China,Clade 2 focus on the Huang river basin and the Clade 3 was distributed on Yangtze river and Pearl river basin.For P.tunguidus,there were 17 haplotypes,two geographic partitions occurred for these subpopulations,Clade 1 only includes Dali,Clade 2 for the others.Finally,we used DNA sequencing of fragments of the COI genes to decide those cases where classical taxonomy does not work well.Our finding of the monophyly of the diaptomidae based on the Bayesian analyses of 55 species and 22 genera is consistent with the conclusions of Kiefer(1932),Shen&Sung(1979)and Reddy(1994)based on morphological data.We reconstructed a well supported ITS phylogeny tree based on 61 species and 22 genera by Bayesian inference and Maximum Likelihood method.Three main clades are grouped by geographic characters and ecological traits.Clade A consists of species distributed in the Palaearctic region;members of Clade B occur in the Oriental region;the contributors of clade C,finally,are carnivores with big sizes that mainly occur in the Nearctic.