Phylogeny and taxonomy of the Australasian Zygaenula Doleschall, 1858 (Diptera: Platystomatidae) with a description of a new species

Zygaenula Doleschall, 1858 and Mesoctenia Enderlein, 1924 syn. nov. are small genera restricted to the Australasia region. Here, both genera are considered synonymous, supported by the synapomorphy width of frons, in relation to height, more than two times. A new species, Zygaenula mcalpinei sp. nov. is described from the Manu Island, Admiralty Archipelago, Papua New Guinea. Zygaenula australis (McAlpine, 1973) comb. nov. , Z. celyphoides (Walker, 1859) comb. nov. , Z. coalescens Hendel, 1914 comb. reinstat., Z. hilaris Hendel, 1914 comb. reinstat., and Z. paradoxa Doleschall, 1858 are redescribed. The lectotype and paralectotype are designated for specimens of Z. celyphoides comb. nov. In addition, an updated identification key and a distribution map are presented. The hypothesised phylogenetic relationship of the Zygaenula species is represented by the following parenthetical notation: ( Z . paradoxa ( Z. coalescens comb. reinstat.. ( Z . hilaris comb. reinstat. ( Z . mcalpinei sp. nov . ( Z. australis comb. nov . and Z . celyphoides comb. nov .))))).