Systematic Study Of The Family Sperchontidae With Morphological And Molecular Phylogenetic Analysis

Sperchontidae is a group, less known from China, of Lebertioidea, Phalanx Hydracnidia, Suborder Parasitengona, Prostigmata, Superorder Actinotrichida, Acari.. Some acarologists suggested that Sperchontidae should be classified as a single superfamily Sperchonioidea. The present works covered taxonomics of the family from China and phylogenetic relationships within the group and among the families of Lebertioidea and related others based on both the morphological and molecular approaches. The paper includes 4 chapters:Chapter One briefly reviewed the development of Acarology, studies in Hydrachnidia, and the classification history of Sperchontidae. Advance in molecular phylogeny of mite are introduced with potential approach.In Chapter Two, 15 species of the Sperchontidae are described. They belong to the subfamily Sperchoninae, two genera (Sperchonopsis and Sperchon), three subgenus {Palpisperchon, Hispidosperchon and Sperchon) separately, of them 1 species is new to science, Sperchon(Hispidosperchon)jianfengensis sp. nov., and 3 newly recorded from China, Sperchonopsis echphyma, Sperchon (Palpisperchon) mirabilis and Sperchon (Hispidosperchon) placoderma. Keys to the genera and to the known species from China are given.Chapter Three focused on reconstructing of phylogenetic relationships, by means of cladistic analysis using 22 morphological characters, among genera and subgenera in Sperchontidae and families in Lebertioidea and close superfmilies. The result showed that phylogenetic relationships of 11 Sperchontidae genera and subgenera do not agree with that proposed by Cook (1974). Acadiosperchon should be treated as a subgenus of Notosperchonopsis; genera Illiesiella an Andinosperchon were sister groups and should be treated as two subgenera of Notosperchonopsis. Relationships of with the others consist with that proposed by Cook (1980). Hence, the present paper proposed a phylogenetic scheme with 2 subfamilies, 6 genera, of which 2 genera each contained 4 subgenera.The phylogenetic relationships of 8 Lebertioidea families, based on the cladistic analysis made using 23 morphological and 2 biology characters, suggested by Cook (1974) seems not agree with the nature. And the cladgram showed that Sperchontidae seemed not a family of Lebertioidea, but an independent superfamily from Lebertioidea.The methods for extracting of DNA were compared for optimizing conditions of CTAB, Chelex-100 and PCR. By a modification method of the CTAB. Fragments of mtDNA CO I gene in Atractides (Atractides) latisetus and fragments of 28S rDNA D3 gene in Sperchon (Hispidosperchon) oligospinis and Lebertia (Pilolebeitia) trifurcilla were sequenced. The homologous sequences for mtDNA CO I of 7 species of mites were downloaded from the GenBank data library. Phylogenetic tree were reconstructed using the sequences of mtDNA COI of the eight species with MP, ML and NJ of software PAUP*4.0. The result showed that Sperchontidae should not be an independent superfamily in hierarchy, but further examining of the conclusion should be made once there are more available sequences of the fragment.