Body shape more slender (narrower and thinner) than M. rothei and with much more conspicuous silvery hairs on the head and ventral side. Readily distinguishable from M. sordida by the puncta of the medial pronotum not being transversely elongated, and from M. soror soror by the very feeble elytral costae.

Previously this species has been misidentified in SA as Melobasis rothei, and until November 2020 it was included on these pages under that name. It belongs in the M. nervosa species group based on the key to groups in Levey 2012, whereas M. rothei is in the M. melanura species group.

In the revision of the M. nervosa species group by Levey 2018 it keys out to the endemic WA species M. barkeri. Despite a general resemblance, it differs from M. barkeri in a number of features including the pronotum shape being more rounded laterally and tapered at the posterior, and in lacking reddish violet reflections on the ventral abdomen and elsewhere. As in M. soror soror, the head is densely clothed with long silvery pubescence, but it differs in lacking the stronger elytral costae of that species. It is treated here as a probable new species.

As with M. rothei, adults are strongly associated with Senna artemisioides and their appearance coincides with the flowering time of these bushes. Recently, however, I encountered it in large numbers on flowering Acacia calamifolia in the southern Flinders Ranges.