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Type material. Holotype, unsexed, AUSTRALIA: Queensland: Binna Burra Lodge campground, Gold Coast hinterland, -28.1983, 153.1870, 793 m asl, resting on Lomandra, 29/12/2021, J. M. H. Tweed (ANIC).
Figure 3. Holotype of Excastra albopilosa Tweed, Ashman & Ślipiński, gen et. sp. nov. as it was found; resting on a Lomandra leaf in Binna Burra Lodge campground. A: dorsal. B: lateral.
Diagnosis. Small sized lamiine. Easily recognised by the reddish-orange and black integument, and the dense covering of short adpressed white setae covering the head, thorax, and anterior third of the elytra, with scattered patches in the posterior two-thirds of the elytra. The prominent long erect setae scattered across the body, denser on head, pronotum and anterior third of elytra, forming paired twisted spires in these areas, are also highly distinct.
Description. Integument mostly black; labrum and palpi reddish-brown, mandibles black; scape mostly black, reddish orange basally and dorsodistally; medial longitudinal reddish-orange stripe on each elytron, beginning at approximately 0.25× elytral length and extending to apex, gradually tapers apically before expanding to occupy apical area, rest of elytron black; legs predominantly reddish-orange, some black on ventral surface of all femora, relatively small on profemur, extending to the posterior and dorsal surfaces of the metafemur, tarsi dorsally black and dull-yellow ventrally. Head. Most areas of head densely covered with white setae largely obscuring integument, scattered erect longer setae throughout, notable tufts arising near dorsal margin of upper eye lobe, clypeus bare, palpi sparsely setose. Antennae. Scape densely clothed in short white seta, numerous long erect setae present, concentration of these increasing both ventrally and apically, longest setae approximately equal to length of scape. Pedicel densely clothed in short white setae; numerous long erect setae present, concentration increasing ventrally. Antennomeres sparsely clothed with short fine white setae, sparse ventral fringe of white setae. Thorax. Pronotum densely covered in short white setae largely obscuring integument, densest in a stripe running from top of gibbosity to posterior margin of pronotum, relatively bare patches anteriorly and posteriorly of lateral tubercule base and in posterior constriction; long erect setae scattered throughout, forming paired twisted spires on dorsoanterior margin and dorsally at approximately 0.3× pronotum length, longest setae approximately 0.7× pronotum length. Prosternum densely clothed in short untidy setae. Mesoventrite and metaventrite densely clothed in short white setae largely obscuring integument, untidy on mesoventrite, uniform on metathorax. Scutellum large, densely clothed in short white setae. Elytra. Setae forming distinct pattern; dense area of shorter white setae clothing the basal third of each elytron, tapered from the lateral margins to the elytral suture, forming a posteriorly pointed pentagon in combination, continues unbroken in a narrow line along the elytral suture, expanding in the apical region, longer erect setae scattered throughout; two paired spires of long setae protruding from amongst the denser short setae on each elytron, one near the scutellum and a second nearer the humeral angle and slightly basal of the first; remainder of each elytron covered in numerous small patches of dense white setae, most circular or oval, some merging into each other and/or the setose areas along the elytral suture and apex, most patches with a single long white setae protruding from the centre, patches asymmetrical, integument visible between patches, sparse long erect setae protruding from the areas of unclothed integument. Legs. Coxae densely clothed in short white setae; each femur with sparse covering of short white setae, not obscuring integument, densest in basal two-thirds, scattered longer white setae throughout, longer setae densest ventrally, prominent band of dense white setae on each femur at approximately 0.75× length, band width approximately 0.15× femoral length; tibiae with sparse covering of short white setae, sparse long erect setae present, all tibia with apical ring of coarse yellowish setae; tibial spurs black; setae of mesotibial antennal cleaner yellowish; tarsi with sparse white setae dorsally, some long erect white setae interspersed, setae of tarsal pads yellowish. Abdomen. Ventrites setose, increasing in density posteriorly on each ventrite, relatively bare patches in centre of ventrites 1, 2 and 3; scattered longer erect setae throughout, tufts of long twisted erect setae protruding from lateral margins of ventrites 5.
Dimensions (mm), holotype (unsexed). Total length, 9.7 mm; length of prothorax at centre, 2.3 mm; greatest width of prothorax (across tubercules), 3.3 mm; anterior width of prothorax, 2.2 mm; posterior width of prothorax, 2.5 mm; humeral width, 3.8 mm; elytra length, 6.4 mm; antennal length, 11.9 mm, scape length, 1.6 mm; pedicel length, 0.3 mm; antennomere (A) lengths, A3, 1.9 mm; A4, 1.9 mm; A5, 1.2 mm; A6, 1 mm; A7, 0.9 mm; A8, 0.8 mm; A9, 0.8 mm; A10, 0.7 mm; A11, 0.8 mm; femora (F) lengths, F1, 2.3 mm; F2, 2.2 mm, F3 2.8 mm; tibia (T) lengths, T1, 2.1 mm, T2, 2.1 mm, T3, 2.3 mm.
Figure 3. Holotype of Excastra albopilosa Tweed, Ashman & Ślipiński, gen et. sp. nov. as it was found; resting on a Lomandra leaf in Binna Burra Lodge campground. A: dorsal. B: lateral.
Distribution and habitat. Known only from the holotype collected within the campground of Binna Burra Lodge which is surrounded by Lamington National Park (LNP). LNP is part of the Gondwana Rainforests of Australia World Heritage Area which forms the most extensive subtropical rainforest in the world (Department of the Environment and Heritage 2000).
Biology. Nothing known. The type specimen was found resting on a leaf of a Lomandra sp. (Asparagales: Asparagaceae) within the campground. This is likely to be a casual association only as Lomandra is not known to be a host plant for any other Australian Cerambycidae (Ślipiński and Escalona 2013, 2016).
Conservation status. As this species is known only from a single specimen, there is insufficient evidence to assign it to an appropriate threat category (IUCN 2012). As such, Excastra albopilosa gen. et. sp. nov. should be regarded as Data Deficient. However, the apparent absence of this species from Australian entomological collections suggests it may be rare, possibly owing to a naturally restricted distribution and/or a unique life history (e.g., high host specificity). The discovery of additional specimens is required to provide information necessary to assess its conservation status.
Etymology. The species epithet is derived from the Latin albus meaning “white”, and pilosa which is the feminine form of pilosus meaning “hairy”, in reference to the white hairs that cover much of this species’ body.
Remarks. Despite having collectively examined thousands of Australian Lamiinae specimens in institutions around the world (particularly AS and LGA) and having spoken to numerous other authorities on Australian Coleoptera, the authors are not aware of any specimens of Excastra albopilosa gen. et. sp. nov. other than the holotype. Binna Burra, and Lamington National Park more broadly, have a strong history of entomological collecting, having been a popular field destination for staff, students, and visiting researchers from the University of Queensland Entomology Department, particularly through the 1960s and 70s (G. Monteith pers. comm.). Lamington National Park has also been a popular collecting location for entomologists at the Queensland Museum, including Henry Hacker and Geoff Monteith, as well as many of Australia’s preeminent early Coleopterists such as Arthur Lea and Herbert Carter (G. Monteith pers. comm.). The distinctive and conspicuous appearance of this remarkable new species makes it even more surprising that it has remained undiscovered despite such extensive entomological collecting efforts. Subsequent trips to the type locality by the first author have also failed to reveal any further specimens. It seems likely that as-yet unknown elements of this species biology, ecology, and/or distribution somehow limit collection opportunities.
The exact function of the characteristic setae of this species is unknown. It is possible that the setae provide an unusual form of Batesian mimicry, disguising Excastra albopilosa gen. et. sp. nov. as an insect infected with an entomopathogenic fungi, possibly reducing its palatability to predators. In the similarly white and setose North American velvet ant Dasymutilla gloriosa (Saussure, 1868), research has shown that the setae likely act to regulate body temperature as opposed to disguising the species as an inedible creosote bush seed as was previously hypothesised (Wilson et al. 2020). Thermal regulation may therefore also be a function of the setae of Excastra albopilosa gen. et. sp. nov. Alternatively, the setae may disguise it as a hairy Lepidopteran larvae, the hairs of which often have irritating qualities to deter predators, or they may camouflage it amongst the flowers of Myrtaceae species. Further work is needed to understand the biology and ecology of this remarkable species.