Australian Journal of
Taxonomy
Open-access, online, rapid taxonomy

This is a page from an unpublished manuscript
Please do not distribute it without express permission of the lead author
 

Excastra Tweed, Ashman & Ślipiński, gen. nov.
{zoologyFigureCitations}

urn:lsid:zoobank.org:act:D5D89665-52B2-45FB-BC02-ECFCBEA9BE0B

Type species. Excastra albopilosa Tweed, Ashman & Ślipiński, sp. nov.

{botanyFigureCitations}

Figure 1. Holotype of Excastra albopilosa Tweed, Ashman & Ślipiński, gen et. sp. nov. A: dorsal. B: ventral. Images not to scale.

Figure 2. Holotype of Excastra albopilosa Tweed, Ashman & Ślipiński, gen et. sp. nov. A: dorsal view, cropped to show setal patterning. B: head, oblique view. C: head, frontal view. D: lateral view. Images not to scale.

Diagnosis. Distinguished from all known Australian Lamiinae genera by the combination of the following characters: completely separated eye lobes; absence of apical carina on scape; combined length of antennal segments 3 and 4 much shorter than 5-11 combined; broad lateral tubercule on the pronotum; clavate femora; paired protibial spurs; comb-like antennal cleaner on the mesotibia; twisted spires of elongated setae concentrated around the head, pronotum, and anterior third of the elytra.

Description. Length 9.7 mm; elongate-oval beetle, body ~2.5× as long as wide. Dense covering of short white setae across the head, thorax, and anterior third of the elytra; scattered long setae across much of the body; twisted spires of longer setae on head, pronotum, and anterior third of each elytron. Head. Frontoclypeus declined about 90°. Frontal surface outline rectangular, convex, approximately 0.8× as long as wide. Eyes finely facetted, divided into separate upper and lower lobes, lower lobe taller than upper lobe, upper lobes separated by approximately 0.75× scape length; lower lobes separated by 3× lobe width. Gena about as tall as lower eye lobe. Anterior tentorial pits and frontoclypeal suture weakly indicated. Clypeus short, anterior margin straight, merging with anteclypeus. Labrum anteriorly flat and setose. Mandibular apex coarsely pointed. Maxillary and labial palps fusiform apically. Antennal tubercules broadly separated at base. Antennae. 11-segmented, extending to just beyond the elytral apex. Scape expanded near middle, broadest point approximately 1.5× basal width, length approximately 3× maximum breadth, apical carina absent, posteriorly extends to anterior base of pronotal tubercule, ~3.7× pedicel length. Pedicel approximately as long as broad. Antennomere 4 longer than 3, 3 and 4 combined approximately 0.6× as long as 5-11, antennomere 11 shorter than 10. Sparse ventral fringe of long white setae. Thorax. Prothorax wider than long, length approximately 0.7× breadth (including lateral tubercules); slightly constricted posteriorly; base distinctly narrower than elytral shoulders; lateral margins with large median tubercule, pointed, broad, length approximately 0.8× base. Pronotum with posteriorly directed triangular sulcus at 0.3× length, flanked by weakly raised nodules which converge posteriorly forming a keel shaped gibbosity. Prosternum in front of the procoxal cavity arcuate, rising to procoxae, approximately 0.4× the coxal cavity length; prosternal process narrow, width at narrowest point approximately 0.4× procoxal cavity diameter, convex but projecting less than coxae, expanded slightly posteriorly. Procoxal cavity oval with lateral projection, closed posteriorly. Scutellum large and clearly visible. Mesoventrite in front of mesocoxae rising to mesocoxae; mesocoxal cavities open to mesepimeron; mesoventrital process at narrowest point approximately 0.5× cavity diameter, convex but less strongly so than prosternal process. Metaventrite approximately 1.2× as long as mesoventrite. Elytra. Humeral angles blunt. Elytral disc mostly smooth and polished, sparsely punctuate, those punctures present concentrated basally, punctures smooth-sided. Surface without tubercules. Elytral apices individually rounded. Fully winged. Legs. Procoxae conical, apex higher than mesocoxae. Femora clavate, greatest width at approximately 0.7× length, profemur especially swollen, metafemur slightly posteriorly curved. Tibia straight, all tibia with two short black spurs, mesotibial antennal cleaner comb-like, no obvious sulcus, extending from 0.2-0.9× length. Tarsi five-segmented, tarsal claws smooth and broadly divergent. Abdomen. Five free ventrites; abdominal process acute; length of ventrites as measured centrally relative to length of ventrite 1, ventrite 2 - 0.34×, ventrite 3 - 0.33×, ventrite 4 - 0.37×, ventrite 5 - 0.54×. Pygidium not exposed.

Figure 1. Holotype of Excastra albopilosa Tweed, Ashman & Ślipiński, gen et. sp. nov. A: dorsal. B: ventral. Images not to scale.

Figure 2. Holotype of Excastra albopilosa Tweed, Ashman & Ślipiński, gen et. sp. nov. A: dorsal view, cropped to show setal patterning. B: head, oblique view. C: head, frontal view. D: lateral view. Images not to scale.

Etymology. The genus name is derived from the Latin words ex meaning “from”, and castra meaning “camp”, and is a reference to the discovery of this species within the Binna Burra Lodge campground. Gender feminine.

Remarks. Excastra gen. nov. is placed within the tribe Ancitini based on its strong resemblance to other members of the tribe. It falls within the broad morphological limits given by Ashman et al. (2022): small, oval-bodied, clavate femora, and a relatively long scape. Should further specimens be collected, molecular analyses should be conducted to confirm the tribal placement.