A review of the genus Satonius (Coleoptera: Myxophaga: Torridincolidae): taxonomic revision, larval morphology, notes on wing polymorphism, and phylogenetic implications

Abstract: The genus Satonius Endrödy-Younga, 1997, is revised. Three new spe- cies are described from China: Satonius schoenmanni sp. nov. (Hunan province), S. stysi sp. nov. (Yunnan province), and S. wangi sp. nov. (Zhejiang province). Two additional new species from the Chinese provinces Fujian and Anhui are left undescribed pending the collection of complete specimens and males, respecti- vely. Metathoracic wing venation of S. stysi sp. nov. is shown to differ from the remaining Myxophaga in the presence of the bifurcation of AA3+4, which updates the venation groundplan of the suborder. Anterolateral spine-like projection of the metaventrite and the increased number of apical setae on parameres are defined as adult autapomorphies of the genus. Larvae of S. stysi sp. nov. are described and compared with the larvae of the Japanese S. kurosawai (Satô, 1982). Characters shared by larval Satonius and Ytu Reichardt, 1973 (extremely flattened body covering legs, and modified orientation and unusual morphology of legs) are supposed as parallel adaptations for the larval environment – very thin film of water in seepage habitats. Interspecific wing polymorphism of Satonius is briefly discussed and possible reasons of the wide distribution of the apterous S. kuro- sawai are hypothesized.

Key words: Coleoptera, Myxophaga, Torridincolidae, Satonius, Ytu, new species, larva, Oriental region, Palaearctic region, China, Japan, wing venation, phylogeny, hygropetric habitats.