Endochironomus effusus (Dutta)

Endochironomus effusus Dutta in Dutta et al. (1994: 256).

The description and placement of the adult male of Endochironomus effusus Dutta in Dutta et al. (1994) is based on an inadequate generic concept and does not conform to the diagnosis for Endochironomus Kieffer males (Cranston et al. 1989). The list of features justifying placement of E. effusus in Endochironomus does not do so. Features that negate the generic allocation (derived from the description and communication with P.K. Chaudhuri) include that that antepronotal lobes meet dorsally and do not project forward, the rounded foretibial scale lacks any spur, the tibial combs are conical and strong,, the inferior volsella is relatively short, stout and appressed along the inner gonocoxite, the superior volsella has a digitiform process arising from a broad, transverse base, and the gonostylus is fused inflexibly to the gonocoxite. Dutta et al. (1994) appeared unaware that Endochironomus acutistilus Freeman, to which they recognised affinity, had been placed by Freeman as the type of his genus Conochironomus (Freeman 1961). Although resembling Conochironomus in described features and additional ones examined by P.K. Chaudhuri (emeritus, Burdwan University, pers. comm. 29 November 2015), E. effusus differs from Conochironomus, e.g. in the purported presence of 2 acrostichals and lack of lateral antepronotals. The hypopygium (Dutta et al. 1994: fig. 2d) closely resembles that of C. tobaterdecimus. Following re-examination of the sole remaining paratype of Endochironomus effusus by P.K. Chaudhuri (pers. comm., 2015, mensural features are similar to those in C. tobaterdecimus, excepting ‘numerous setae’ on wing vein R4+5, purported presence of acrostichals and lateral antepronotals. However, the specimen is poorly mounted (P.K. Chaudhuri, pers. comm), making it impossible to assess all features required to confirm generic placement in Conochironomus and it is premature to propose a new generic combination before suitable material becomes available for evaluation.

Locations for E. effusus at 27°N in the Duar foothills of the Himalaya in West Bengal, are at elevations up to 450 m. a.s.l., which is subtropical-temperate compared to the more tropical habitats of Conochironomus in Africa and Australia. However, the most northerly sites at which definitive Conochironomus larvae have been found in Thailand, at about 19–20°N, are at elevations above 600 m a.s.l. and also are cool subtropical to warm temperate.