The genus Dichaetophora Duda comprises 61 described species classified into four species groups: agbo, tenuicauda, acutissima and sinensis. This genus is distributed exclusively in the Old World, and is rich in species in the tropical and subtropical areas of the Oriental, Australasian, and Afrotropical regions. In this paper, a new species group, the trilobita group, is established for six new species discovered from the Oriental region. The delimitation of these species is firstly performed in light of morphology and further with the aid of DNA sequences of the mitochondrial COI and COII (cytochrome c oxydase, subunits I and II, respectively) genes, considering also their respective geographical origins. Then, the new species (trilobita Yang & Gao, sp. n., heterochroma Yang & Gao, sp. n., flatosternata Yang & Gao, sp. n., borneoensis Yang & Gao, sp. n., javaensis Yang & Gao, sp. n., and sumatraensis Yang & Gao, sp. n.) are described, and a key, based on not only morphological but also molecular information, is provided.
The zeylanica group is one of the six species groups of the anthophilic genus Colocasiomyia de Meijere in the family Drosophilidae. In addition to two known species, five morphospecies have been recognized as members of this species group but left undescribed formally. In this study, species delimitation of these putatively new species was determined by barcoding of the mitochondrial COI (cytochrome c oxydase subunit I) gene and morphological comparison. Phylogenetic relationships within the genus Colocasiomyia were inferred by a cladistic analysis of 89 morphological characters. Based on the results of these analyses, we redefined the zeylanica species group and established two subgroups within it: the zeylanica subgroup comprised of C. zeylanica, C. nepalensis, C. pinangae sp. nov., C. besaris sp. nov. and C. luciphila sp. nov., and the oligochaeta subgroup of C. oligochaeta sp. nov. and C. grimaldii sp. nov. In addition, we briefly address the anthophilic habits of drosophilid flies using palm (Arecaceae) inflorescences, especially of the zeylanica group, compiling scattered collection records from the Oriental and Papuan regions.
The subgenus Dudaica Strand of the genus Drosophila Fallén has been known to comprise only two species: Drosophila (Dudaica) senilis Duda, 1926 (recorded from Indonesia, Philippines, Vietnam, Bhutan, and India) and D.malayana (Takada, 1976) (recorded from Malaysia). In the present study, this subgenus is revised, with D.malayana redescribed and six new species discovered and described from China, Malaysia, and Indonesia: gracilipalpis Katoh & Gao, sp. n., puberula Katoh & Gao, sp. n., albipalpis Katoh, Toda & Gao, sp. n., qiongzhouensis Katoh & Gao, sp. n., orthophallata Katoh, Toda & Gao, sp. n., and dissimilis Katoh & Gao, sp. n. Both morphological and molecular data (DNA barcodes) are used to distinguish the above species. A key to species of this subgenus is provided.