A new black fly species, Simulium (Gomphostilbia) pangsidaense, is described on the basis of adult female, male, pupal exuviae and mature larvae from Pang Sida National Park, Sa Kaew Province, Eastern Thailand. This new species is placed in the Simulium ceylonicum species-group. It is distinguished from three Thai members of the S. ceylonicum species-group by the following characteristics: from S. (G.) curtatum Jitklang et al. and S. (G.) sheilae Takaoka & Davies by the wide pupal terminal hooks (triangular terminal hooks in the latter two species), and from S. (G.) sheilae and S. (G.) trangense Jitklang et al. by the number of male upper-eye facets in 13 vertical columns and 14 or 15 horizontal rows (10 or 11 vertical columns and 12 or 13 horizontal rows in the latter two species). This is the fourth member of the S. ceylonicum species-group recorded from Thailand.
Perspicuous assessments of taxonomic boundaries and discovery of cryptic taxa are of paramount importance in interpreting ecological and evolutionary phenomena among black flies (Simuliidae) and combating associated vector-borne diseases. Simulium tani Takaoka & Davies is the largest and perhaps the most taxonomically challenging species complex of black flies in the Oriental Region. We use a DNA sequence-based method to delineate currently recognized chromosomal and morphological taxa in the S. tani complex on the Southeast Asian mainland and Taiwan, while elucidating their phylogenetic relationships. A molecular approach using multiple genes, coupled with morphological and chromosomal data, supported recognition of cytoform K and morphoform 'b' as valid species; indicated that S. xuandei, cytoform L, and morphoform 'a' contain possible cryptic species; and suggested that cytoform B is in the early stages of reproductive isolation whereas lineage sorting is incomplete in cytoforms A, C, and G.
Simulium (Gomphostilbia) sofiani sp. nov. is described on the basis of reared adult female, male, pupal and larval specimens collected from Cameron Highlands, Pahang state, Malaysia. This new species is placed in the ceylonicum species-group within the subgenus Gomphostilbia and is easily distinguished from all the related known species by the combination of the following characteristics: an elongate sensory vesicle and yellow hair tuft on the stem vein of the wing in the female, the greater number of large upper-eye facets (15 or 16 vertical columns and 15 or 16 horizontal rows) and almost entirely darkened hind basitarsus in the male, and the gill bearing a long common basal stalk and 8 filaments arranged as [(1+2)+(1+2)] +2 filaments from dorsal to ventral in the pupa.