Diagnosis (minor worker). Dorsum of mesosoma with abundant, bright yellow enlarged hairs; metapleural gland present.
Description (minor worker). Posterolateral surface of head rounding gradually from the dorsal to lateral surfaces, the lateral surface weakly concave in smaller workers, convex in larger workers. Petiolar node forming a sharp angle dorsally and with a slight anterior tilt. Enlarged bright yellow hairs abundant on pronotum (except extreme anterior edge), mesonotum and gaster, those on the propodeum limited to near the angle; appressed pubescence present but sparse. Colour dark red-black to black.
Measurements. Minor worker (n=4): CI 84-92, HL 1.86-2.29mm, HW 1.57- 2.08mm, ML 3.04-3.63mm, MTL 2.43-2.78mm, SI 162-194, SL 2.61-2.94mm.
Additional material: Australia : Queensland : 2.5km SW Mt. Hartley, 35km S Cooktown ( Monteith, Yeates & Cook ) ( ANIC ) ; Mt. Finnigan, 37km S Cooktown ( Monteith, Yeates & Cook ) ( ANIC , LACM ) ; Mt. Finnigan summit, via Helenvale ( Monteith, Cook & Roberts ) ( ANIC ) ; Mt Misery road , 15°53'S145°13E , 730m ( ANZSES Expedition ) ( QM ) ; Mt Misery road , 15°53'S145°13E , 500-850m ( ANZSES Expedition ) ( QM ) .
Comments. This species is unusual in that it is only the second species of Camponotus known to have a metapleural gland, the other being the South-east Asian C. gigas . The opening to the gland is large and highly visible, in fact as large as any known in the ants. This is especially noteworthy as none of the other species examined here show any indication of a metapleural gland being present. Also, thadeus is morphologically distinct from gigas , sharing few characters with it and with little indication that they are closely related. It is therefore highly likely that this gland has reappeared independently in these two taxa.
The following observations were made by Angela Shuetrim (pers. comm.) while collecting the type series on Mt. Finnigan, Queensland:
FIGURES 22-24. C. thadeusnew species , minor worker. Fig. 22, front of head; Fig. 23, dorsum of mesosoma; Fig. 24, side of body.
"These ants are arboreal based on the nest I found. Nests are very difficult to locate but I was lucky enough to find one in a hollow cavity in a tree. The locality was in rainforest at high elevation, the lowest elevation where I found them being approximately 880m, and I never came across them in lowland rainforest areas. The vegetation changes frequently as you walk up the mountain and when you get to the right spot, and weather conditions are good, they can be found in high numbers running up trees along trails, and scattered across the rainforest floor."
Sole species in group. Worker. HW 2.00 - 3.20; HL 2.15 - 2.80; PW 1.85 - 2.15. Black; mesonotum, propodeum and anterior gaster with dense bright yellow setae up to 1 mm long, scapes and tibiae with short setae raised to 20°, no erect setae on underside of head; mesosoma finely reticulate, head finely punctate; metapleural gland opening 0.25 - 0.27; head sides straight tapering forward, widest behind eyes. Major worker. Vertex feebly concave; eyes distant from corners by more than EL; anterior clypeal margin feebly projecting, median section concave between two rounded convexities. Minor worker. Anterior clypeal margin feebly projecting, mostly straight; vertex straight; eyes near corners.
