Megachile (Hackeriapis) lucifer (Hymenoptera, Megachilidae), a new megachilid with demon-like horns that visits the Critically Endangered Marianthus aquilonaris (Pittosporaceae)

A new species Megachile (Hackeriapis) lucifer (Hymenoptera: Megachilidae) is described from both sexes. Megachile lucifer sp. nov. is of conservation importance, as it is a visitor to the range-restricted, Critically Endangered flowering plant species Marianthus aquilonaris (Pittosporaceae). This new Megachile has yet to be collected outside the region in which this rare plant occurs. A diagnostic feature of Megachile lucifer is the presence of a large pair of outward and upwardly facing, convex horns on each side of the clypeus, which is deeply recessed and features a medial ridge. These horns are found only in the female, unlike most sex-specific weaponry or ornamentation in animals. Clypeal modifications occur in a number of female megachilids which may be related to nest construction, whilst other clypeal horns are found in Hackeriapis females. The description of this new species provides the opportunity for future research into their function, and evolution among this subgenus. DNA barcoding with the CO1 gene confirmed the sexes belonged to the same species and it did not match any previously barcoded species. The species was collected only during mass-flowering of another host, Eucalyptus livida (Myrtaceae). The limited known distribution, and short activity season of this species, along with being associated with a Critically Endangered plant species in a region subjected to mining, suggested it may be a species of conservation concern.