Platybracon Yang et al. (2008) (Hymenoptera: Braconidae), junior homonymy and subjective synonymy--a systematic and nomenclatural note.

Yang et al. (2008) described a distinctive, small braconine wasp, Platybracon sinicus, from China as a new genus and new species. They discussed similarities with other braconine genera and to which genus it would belong to when using the only available key to the Braconinae (Quicke, 1987). However, they failed to notice that their genus name Platybracon would be a junior homonym of Platybracon Szépligeti, 1900. Additionally, Platybracon is itself a junior subjective synonym of Chaoilta Cameron 1899, also a member of the Braconinae, synonymised by Baltazar, 1966 and upheld by Quicke (1987). Platybracon sinicus described by Yang et al. does not belong to the genus Chaoilta, which belongs to the Aphrastobraconini (sensu van Achterberg 1989) but instead is a member of the Plesiobracon genus group of the Braconini. Whilst noting the similarity between their genus and Crinibracon Quicke, 1988, Yang et al. separate the two genera on the basis of the following four characters (states given are those of Platybracon Yang et al.): “... 2nd metasomal tergite with a pair of flexural sublateral grooves, length of vein r of forewing about being equal to vein 2-SR of forewing; posterior margin of sixth tergite without broad emarginated [sic!] medially; vein 1-M of forewing gradually thickening and slightly curved.” These characters alone do not appear to us to be sufficiently strong for the recognition of a second genus (which would require a replacement name for Platybracon Yang et al.) and should instead be placed in the genus Crinibracon Quicke, 1988 of the tribe Braconini. The principal difference seems to be the sublateral grooves on the 2nd tergite in P. sinicus that are absent, probably apomorphically so in the three other described species. The emargination of the midposterior margin of the 6th metasomal tergite in the other species of Crinibracon is very slight and, indeed, not visible in dorsal view. The proportions of fore wing vein r and the veins of the 2nd submarginal cell are quite often variable within genera of Braconini. From Yang et al.’s illustration of wing venation, we can not see what is meant by their statement about vein 1-M but it appears not obviously different from that of Crinibracon. The smoothly rounded apical expansion of the dorsal ovipositor valve suggests that P. sinicus may be most closely related to C. striatus Quicke, and this morphology is otherwise unique within the subfamily. We consider Platybracon Yang et al. is a junior subjective synonym of Crinibracon Quicke, hence we propose Crinibracon sinicus (Yang et al. 2012) comb. nov. as a junior homonym of Platybracon Szépligeti. The genus Crinibracon has been recorded from China, India, Malaysia, and Papua New Guinea (Quicke, 1988; Yu et al., 2012). Nothing is known about its biology.