Beetle evolution in the Asian highlands:: insight from a phylogeny of the scarabaeid subgenus Serica (Coleoptera, Scarabaeidae)

The phylogeny of the species of the scarabaeid subgenus Serica (genus Serica MacLeay, 1819) was inferred from a parsimony analysis and the use of 117 morphological characters of adults. Successive weighting was employed to further evaluate the phylogenetic relationships, and the geographical changes in the distribution in certain lineages were explored. Four major lineages may be recognized from the strict consensus tree within the ingroup: (1) Calloserica; (2) Gastroseric + Neoserica; (3) Lasioserica; and (4) Serica including the representatives of Taiwanoserica. Pachyserica proved to be monophyletic only after successive weighting based on the retention index. The taxa of Taiwanoserica are nested within the species of Serica. Consequently, Taiwanoserica (stat.n.) is ranked as a subgenus of Serica. The clade Serica (subgenus Serica) comprised the majority of the species included in this study. Serica (sensu stricto) species of the Himalayas are a polyphyletic group. Several major younger clades of Serica (sensu stricto) are not restricted to just one geographical region, but cover widely distant ranges (such as the Himalaya and eastern Tibet). Dispersal is hypothesized multiple times from the Himalaya to eastern Tibet/Indochina and vice versa, and also between the Japanese islands and eastern Tibet. Several hypotheses are discussed for an important role of the entire Himalaya-south-eastern Tibet orogenic system for the evolution of the subgenus Serica. More recently, the progressive uplift of the Tibetan Plateau provided an efficient barrier to the westward dispersal of eastern Palaearctic species.