Distributions patterns of Cixiidae (Hemiptera, Fulgoroidea) in China highlight their high endemic diversity

Does the distribution of the Hemiptera planthoppers Cixiidae, follow the patterns of biogeogaphical distribution already well established for their host plants or other taxa because they are all obligatory phytophagous taxa? Are their realms and boundaries recognized? What are their zoogeographical regions and usual connections? To investigate these issues, we provide here a referenced and comprehensive checklist of the 253 cixiid species currently reported from China, with their precise distribution at the regional level. Seventy seven of these species are new records for China. In the 8 Chinese main zoogeographical regions usually recognized and 2 adjacent areas, we analyzed further their diversity at the tribal, generic and specific levels using a non-metric multidimensional scaling and an unweighted pairwise group analysis using an arithmetic mean cluster analyses. The observed distribution patterns have shown that an intercalary Sino-Japanese realm is present between the Palaearctic and Oriental realms. At the regional level, the South China region cluster is more closely with the Southwest, Central and North China regions. Taiwan is clearly separated from the South China region and mainland China, but is more closely related to the Qinghai-Tibet region and Indochina countries. The Central and South China regions are close to each other, but the Qinghai-Tibet region is singularly different. An updated checklist of the 253 Cixiidae species currently known to occur in China that composes 10% of the Chinese planthopper fauna, is presented, based on original literature, collections in institutions, and museum records. More than 400 records distributed among the 28 provinces and regions in China are provided including 77 new records for China. More than 80% of the species (205 species, 81.03%) have been only reported from China, and most of them are Chinese endemic species, which reflects the great diversity of the Chinese regional and local biotypes and highlights the uniqueness of this fauna. These species are found in 8 zoogeographical regions in China: The Taiwan region is the most diversified with 161 species and the highest rate of endemic species (70.81%), followed by South China (76 species, 17.11%), Central China (62 species, 35.48%), Southwest China (42 species, 40.48%), North China (29 species, 34.48%), Qinghai-Tibet region (10 species, 20%), Northeast China (8 species, 12.5%), and 5 species found in the Inner Mongolia-Xinjiang region that are not endemic. Thirty eight main distribution patterns were identified, and 9 of them were bi-regionally and tri-regionally distributed. The South China-Taiwan pattern has the highest proportion of these major distribution patterns followed by the Central-South China-Taiwan pattern. Semonini and Pentrastirini tribes are widespread among the 8 Chinese zoological regions, representing, respectively, 20.55% and 17% of all species of Chinese cixiids. Cixiini are the most common species of planthopper composing of 45.85% of the total planthopper species found in China , and they occur in 7 Chinese regions but are absent from northeastern China. The next most common Tribes are: Andini with only 5.14% of these species distributed in the Sino-Japanese - Oriental Region; Eucarpini (6.32%) and Borysthenini (1.98%), which are mainly concentrated in the south of the Qingling Mountain-Huai River. The remaining four tribes, Bennini (0.40%), Brixini (0.79%), Oecleini (1.58%) and Stenophlepsini (0.04%) are relatively rare and restricted to Taiwan. A non-metric multidimensional scaling and an unweighted pairwise group method analysis using arithmetic mean clustering based on the Jaccard similarity coefficient matrix support a Palaearctic/Sino-Japanese boundary and a South China region closer to the Southwest, Central and North China regions. The Taiwan region appears clearly separated from the South China region and to mainland China, but more closely related to the Qinghai-Tibet region and Indochina countries. The Central and South China regions appear close to each other, but the Qinghai-Tibet region is singularly isolated.