Taxonomic Research Of The Spider Family Dictynidae From China(Arachnida: Araneae)

The meshweb spider family,Dictynidae O.Pickard-Cambridge,1871,belongs to Araneae,Opisthothelae,Araneomorphae,Entelegynae,RTA clade and Dictynoidea.Presently,there are 470 species in 50 genera widely distributed in all continents except Antarctica,among of which,62 species in 14 genera have been recorded from China.From the perspective of evolutionarily and phylogenetically,dictynid spiders were thought as a transitional group evolving from underground to ground,and then making webs in the air or hunting.Dictynid spiders have a strong adaptability to some extreme environments,such as coastal intertidal zone(Qiongdictyna),under-freshwater(Argyroneta aquatica),saline-alkali area of deserts(Devade)and natural caves(Brommella and Cicurina)etc.,which is rare at a level of spider family.Dictynid spiders is an indispensable group for the systematic evolution of Araneae,as well as an ideal material for the research of living in low oxygen,salt tolerance or dark resistance environment.Therefore,the basic study of dictynid spiders' taxonomy would be very important.Due to the reason of small body size,less quantity and difficulty of collecting,the research on dictynid spiders around the world lags far behind other groups,with few revisions only reported in North America,New Zealand and Sweden.Studies on dictynid spiders in China started relatively late.In the early stage,all kinds of studies were conducted by foreign scholars.There were some problems such as the low-resolution appended figures,overly simplistic description and the difficulty in checking type specimens,which brought great difficulties to the later scholars.There are also many taxonomic problems,such as homonyms and wrong identification,which limit the further research of the dictynid spiders.In this paper,based on a great deal of specimens(newly collected and loaned),a morphological taxonomy of dictynids from China was thoroughly conducted.In the general account,the natural history,somatic and genital morphology,biology and geographic distribution of Chinese Dictynidae were generalized.Also the taxonomic status and systems of Dictynidae were preliminary analyzed based on the comparison of morphological and genital characteristics.The result shows consistency of the analysis in Griswold et al.(2005)that Dictynidae belong to the RTA branch,while disagree with the division between the Dictynoidea and Amaurobioidea for both of which include groups belonging to the same branch----Amaurobioids.However,further research is needed to understand the relationships among the Amaurobioids included in this group.In the taxonomic account,155 species in 18 genera of Chinese dictynids were photographed,illustrated and described.Including four new genera(Diandictyna gen.nov.,Qiongdictyna gen.nov.,Sublathys gen.nov.and Zangdictyna gen.nov.),one newly recorded genus(Tricholathys Chamberlin & Ivie,1935),three newly recorded species from China(Dictyna mitis Thorell,1875,Lathys alberta Gertsch,1946 and Tricholathys relicta Ovtchinnikov,2001.),revalidation of five species' status(Devade qiemuensis(Hu & Wu,1989)stat.rev.,Dictyna lhasana Hu,2001 stat.rev.,Dictyna mitis Thorell,1875 stat.rev.,Dictyna nangquianensis Hu,2001 stat.rev.,Dictyna wangi Song & Zhou,1986 stat.rev.),seventy-nine new species,two specific misidentifications(Argenna subnigra and Nigma flavescens)),seven new species-level synonyms,eleven new specific combinations,two species with first description of female(Ajmonia nervifera and Cicurina majiangensis),six species with first description of male(Brommella sejuncta,Brommella wangfengcheni,Cicurina damaoensis,Cicurina zhazuweii,Sudesna flavipes and Sudesna linzhiensis)and fifteen species groups were recognized.A total of 124 illustrational plates of genital together with 159 photographic plates of habitus and copulatory organs were given.The present study is a part of work in the study of Araneae's taxonomic revision in China,providing a basic data for phylogenetic relationship and system evolution to spider's research,it also provide some detailed information of the Chinese fanua in dictynid spiders for the world and for the further research.