Rhopalothrix diadema

Other than a few brief specimen label remarks ("soil-leaf litter berlesate from lowland rain forest on the lower Busu River" col. Wilson, "secondary rainforest" col. Janda), nothing is known about the biology of .

Identification
Key to Rhopalothrix workers

Distribution based on Regional Taxon Lists
Indo-Australian Region: New Guinea.

Castes
Known only from the worker caste.

Nomenclature

 *  diadema. Rhopalothrix diadema Brown & Kempf, 1960: 239, fig. 59 (w.) NEW GUINEA.

Worker
Holotype. TL 2.2, HL 0.52, HW 0.61 (CI 117), ML 0.22, WL 0.53 mm.

A very shallow sulcus crosses head just in front of the anterior arc of large round hairs. Eyes minute, each situated on underside of dorsal scrobe border and beneath one of the large hairs, so not visible from dorsal full-face view. Mandibles narrow, curved, with 4 or 5 spaced denticles; subapical tooth longer than basal width of mandible and slightly longer than (ventral) apical tooth; between subapical and apical teeth 2 blunt, indistinct intercalary denticles. Labrum flat, but with a large mediobasal tumulus (indicated by a dotted line in the figure) and a shallow anteromedian longitudinal sulcus leading to the tiny groove between the two narrow lobes, which together with their short, approximated sensilla, form an acute apex to the lateral shield. Antennal scapes convex above, but with a concave strip along the anterior edge.

Alitrunk compact, convex in outline, its summit at the posterior edge of mesonotum. A broad but shallow sulcus separating pro- and mesonotum, and a slight metanotal groove separating mesonotum from down-sloping propodeal dorsum. Seen from above, pronotum much broader than long, with rounded sides; mesonotum much smaller, suhcircular; distinct constriction at metanotal groove; sides of propodeum convex in front. Propodeum with median portion of surface continuous from dorsum to declivity and concave from side to side, guarded on each side by an obtuse angle (vestige of the propodeal tooth) trailing a low cariniform lamella below.

Petiole with a distinct but broadly conical peduncle and a rounded node, distinctly broader than long as seen from above. Postpetiole sub reniform, nearly twice as wide as petiolar node and about 2/3 as wide as widest part of gaster. Gaster oval, convex above and below, without a dorsal sulcus or impression.

Entire body densely and finely granulose-punctulate, opaque; promesonotum and petiole with fine superimposed rugulae. Ground pilosity consisting of round, white, subappressed squamiform hairs, abundant over head, scapes, labrum, promesonotum, legs, both nodes and gaster; largest on clypeus, pronotum, tibiae and gaster; smaller and inconspicuous on mandibles and petiolar node. Larger specialized hairs are shaped like the inverted bowls of broad, flat spoons lying close to and paralleling the integumantal surface; in perpendicular view, they look like large, round white scales: 18 on head, arranged as shown in Fig. 59; 2 pairs on mesonotum, 1 pair on posterior petiolar node, 1 pair on posterolateral corners of postpetiole; about 24 on first gastric tergite; 2 hairs at each tibial apex. Gastric apex with more or less erect clavate hairs both above and below. Color light ferruginous.

Type Material
Holotype worker taken in a soil-leaf litter berlesate from lowland rain forest on the lower Busu River, near Lae, New Guinea (E. O. Wilson leg., no. 1052). In the same Berlese sample were associated the ant species Eurhopalothrix biroi, E. brevicornis and Dacetinops cibdela Brown & Wilson.

Three paratype workers also from the same sample vary slightly in size and proportions: TL 2.1-2.4, HL 0.51-0.55, HW 0.59-0.65 (CI 116-118), ML 0.21-0.22, WL 0.52-0.56 mm, but are otherwise very similar. Paratypes in, , WWK.

Longino and Boudinot (2013) - Holotype, worker: New Guinea, lower Busu River, near Lae, lowland rainforest (E. O. Wilson, no. 1052) (not examined).