Systematics Of Tomoceroidea Szeptycki,1979(Collembola:Entomobryomorpha)

The thesis reports the systematic study on Cllembola superfamily Tomoceroidea Szeptycki,1979, which by now contains two families, Tomoceridae Schaffer,1896and Oncopoduridae Carl&Lebedinsky,1905. The context is split into two chapters:Ⅰ, morphological systematics; Ⅲ, biogeography and species delimitation based on molecular data.In the first chapter, the taxonomic characters are reviewed, including the features on the antennae, the mouthparts, the body appendages and the chaetotaxy. Three characters, the distal whorl of chaetae on the tibiotarsi, the lateral row of pseudopores and the distal corner chaetae on the manubrium, are newly discovered to be certainly or potentially of taxonomic value for Tomoceridae. Not only the mature characters but also the juveniles of Tomocerinae Schaffer,1896have been surveyed. The chaetotaxy of the first instar of Tomocerus minor (Lubbock,1862) and Tomocerina varia (Folsom,1899) have been examined and compared with the primary tergal chaetotaxy of Pogonognathellus (Borner,1908) described by Szeptycki (1972). Distinct differences have been found among the primary chaetotaxy of the three genera, confirming the phylogenetic divergence of the three branches. Comparison of the primary characters supports the independence of Tomocerinae and may indicate a closer relationship between Tomocerinae and Isotomidae Schaffer,1896than other groups among Entomobryomorpha Boner,1913. This chapter also includes the classification of Tomoceroidea. A remarkable new genus Sinoncopodura gen. nov. has been described in the small family Oncopoduridae from Zhejiang Province, China. It differs from the other two genera in the absence of the modified chaetae (e.g. spines, crooks or scales) on dens, the highly modified labrum and labral chaetae, the absence of the clavate chaetae on tibiotarsus, and the unusual structure of the mucro. Its relationships with other genera are discussed, further resulting in the redefinition of the family Oncopoduridae. Lepidophorella flavescens (Nicolet,1847) is redescribed in detail and a species of Lepidophorella Schaffer,1897is described from New Zealand, the position of Lepidophorellinae Womersley,1939is discussed. A new cave tomocerid species Tomocerus caecus sp. nov. from Guangxi Zhuang Autonomous Region is described. This species is not only the first eyeless tomocerid from China but also the first eyeless species of the genus Tomocerus Nicolet,1842. Two special characters of this new species, the long teeth on the maxillary lamella5and the inner pointed scale on dens raise a discussion on the differences between the genera Tomocerus and Pogonognathellus. The genus Tomocerina Yosii,1955was generally reviewed with description of a new species and revision and redescription of a known species. Two species Pogonognathellus heterochros Wang, Yu&Zhang,2013and Pogonognathellus mai Wang, Yu&Zhang,2013were described from Changbai Mountain, which were the first record of new Pogonognathellus species from China, and the Eastern Asian members of this genus were discussed. Four new species of Monodontocerus Yosii,1955were described from China, the monophyly of this genus is supported by reassessing its generic characters. Four species of Plutomurus has been re-examined, supplementary description of Plutomurus jeleznovodskii Kniss&Thibaud,1999is provided, and the chaetotaxy and mucronal structure of this genus are discussed. Several other new species are described, including new species identified from the former Chinese "Tomocerus ocreatus Denis,1948". A preliminary phylogenetic analysis of Tomocerinae has been performed on the basis of a morphological data matrix including54characters and40taxa. The strict consensus tree indicates two main clades within Tomocerinae and recovers three monophyletic genera, Plutomurus Yosii,1956, Pogonognathellus and Monodontocerus, while Tomocerus sensu stricto and Tomocerina are suggested to be polyphyletic.The second chapter reports the molecular study on two Chinese Tomocerus species group, ocreatus-complex and nigrus-complex, which are respectively distributed in the southern and northern parts of China. There is a poor understanding of the species diversity within these complexes and of the factors affecting their diversification and dispersal. Species delimitation using a general mixed Yule-coalescent model and a Bayesian multi-locus approach recognized23DNA-based species. In addition to genetic differences, corresponding morphological differences in jumping organs among the major clades are discovered. Analyses of divergence times and historical biogeographic revealed that ocreatus and nigrus complex originated respectively in southern and northern China. Their divergence time is estimated at27.8-44.9Mya during the Eocene-Oligocene, when the transmeridional Qinling-Dabie Mountains uplifted and formed the north-south geographical boundary of eastern China. Diversification analyses suggest that the subsequent orogenesis of the Qinghai-Tibetan Plateau in western China had little impact on divergences within the two species complex so that they maintained their geographical patterns from the Paleogene to the present day. These findings also point to a potentially important influence of the Qinling-Dabie Mountains on patterns of animal speciation and distribution in China.