Skolomystax, a new genus for the Australian species formerly included in Centroptilum Eaton (Ephemeroptera: Baetidae)

Abstract

A new genus, Skolomystax n. gen. is described to include the Australian mayflies previously assigned to the genus Centroptilum (Baetidae). Based on an integrated taxonomic analysis of mitochondrial cytochrome oxidase I and morphology, 12 species are assigned to this new genus, comprising two new combinations, S. elongatus (Suter, 1986) n. comb. and S. collendus (Harker, 1957) n. comb., and ten new species described in the nymphal stage: S. brevis n. sp., S. chionotos n. sp., S. dyarrbi n. sp., S. gippslandicus n. sp., S. goorudensis n. sp., S. hawkingi n. sp., S. leichhardti n. sp., S. paschei n. sp., S. tasmaniensis n. sp., and S. vulgaris n. sp. A species known only from the original description by Harker (1957) is assigned as S. collendus n. comb.; the type material is lost, so it is not treated in detail and its validity remains uncertain. Adults of S. elongatus, S. hawkingi n. sp. and S. leichhardti n. sp. are also included. Skolomystax is closely related to Apobaetis, Callibaetis, Callibaetoides and Waltzoyphius, but differs from them in the combination of a wide notch in the labrum with a basal pair of denticles, 3-segmented maxillary palps, hind wing pads present, and single gills without folds. A key to the nymphs of all species of Skolomystax, except S. collendus, is given.