Melanterius costatus (Lea, 1899)

(Figs. 26–27)

Melanteriosoma costatum Lea, 1899: 267

Melanterius uniseriatus Lea, 1899: 245; Pullen et al., 2014: 227 (syn.)

This short, stocky species was described from Sydney and occurs more widely in New South Wales and into southern Queensland, but it appears to be uncommon. It is characterised by having the elytral interstriae 3 and 5 sharply and conspicuously costate and an irregular row of black setae on either side of the median elytral ridge, together forming a chevron pattern. It also has a distinct, high, oblique carina on either side of the disc of the metaventrite, stretching between the middle of the meso- and metacoxae, but it shares this feature with M. inconspicuus (see below). Lea (1909) described an alleged subspecies of it from Tasmania, as Melanteriosoma costatum var. tasmaniense, but this does not possess the carina between the meso- and metacoxae and also differs in some other characters and is here treated as a distinct species (see below). The penises of these three species also differ, the body in M. costatus (Fig. 27) having straight sides and a broadly, evenly rounded apex. The synonymy of Melanterius uniseriatus with M. costatus was proposed by E. C. Zimmerman in his manuscript on Melanterius but only published by Pullen et al. (2014); the unique but damaged type of uniseriatus (abdomen missing and head glued separately on the card of the specimen), in Lea’s collection, needs re-examination though as a female identified by Lea as M. uniseriatus, from Ferguson’s collection and now in the ANIC, is conspecific with M. inconspicuus (below).

No hosts have been recorded for M. costatus . Four specimens in the ANIC are labelled as having been collected on Acacia irrorata, and we collected it on this species, too, and on an unidentified Acacia species.