Chetoneura Colless

Amorim, Dalton De Souza & Clarke, Arthur K, 2008, Chetoneura shennonggongensis, a new species of cave – dwelling Keroplatini from China (Diptera: Keroplatidae), with a discussion of the position of Chetoneura, Zootaxa 1716, pp. 59-68 : 60

Chetoneura Colless

Chetoneura Colless 1962: 437 . Type –species, Chetoneura cavernae Colless , by original designation.

Diagnosis. Adult mouthparts reduced, two ocelli, flagellum laterally compressed, mediotergite weakly sclerotized, with a group of setae medially. Wing vein R4 absent; wing veins dark, membrane brownish, but without maculation. Gonostyle of male club–shaped, not bifid. Female terminalia with largely developed gonapophyses 8, entirely involving the distal part of the terminalia. Larva inhabiting caves.

Comments. Colless (1962) listed some features present in his new species C. cavernae as diagnostic of the genus Chetoneura . Among them are the flattened flagellomeres, the presence of only two ocelli, reduced mouthparts, presence of anepisternal setae, no postspiracular setae, laterotergite bare, regular rows of tibial setulae, and unbranched R4+5. All these features are present in the species collected in Shennong Gong, herein described. The features that differ are the absence of “strong bristles dorsally” on the “metanotum”, the short fusion of M1+2 with Rs, and the absence of a distal spine on the male gonostyle. However, there are additional features that suggested relationship between the two species, such as the general shape of the male terminalia, elongated anteriorly, the concentration of setae internally on the gonocoxites, the dorsal lobe of the gonocoxites, and the very unusual shape of the female sternite VIII. Even though the larval habitus of Chetoneura cavernae is not described, the fact that both species were collected in caves and other apomorphic morphological features suggest that the genus is monophyletic. Two other papers ( McClure et al. 1967, Dittmar et al. 2005) have made reference to the Malaysian species of Chetoneura . In the original description, the position of the genus was not clear. Colless (1962) noted some features that are similar in Chetoneura and Keroplatus , such as the reduced palpus, but also listed a number of shared characteristics with Orfelia , and concluded that Chetoneura has a closer relationships to Orfelia than Keroplatus . This may have been the reason why Matile (1990) did not include the genus in the Keroplatini in his phylogenetic analysis of the tribe. The genus Chetoneura is herein formally transferred to the tribe Keroplatini .