Eurhopalothrix brevicornis

E. O. Wilson collected a small series of workers and a stray at the Lower Busu River, near Lae, New Guinea, hy Berlese funnel from rain forest leaf litter. The MCZ has two workers taken by K. P. Schmidt from a bird's-nest fern at Rabaul, New Britain. (Brown and Kempf 1960)

Identification
Key to Old World Basicerotini

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

Nomenclature

 *  brevicornis. Rhopalothrix brevicornis Emery, 1897c: 572, fig. 19 (w.) NEW GUINEA. Szabó, 1910a: 367 (q.). Combination in Eurhopalothrix: Brown & Kempf, 1960: 215. Senior synonym of mixta: Brown & Kempf, 1960: 215.
 * mixta. Rhopalothrix mixta Szabó, 1910a: 366, fig. 4 (w.) NEW GUINEA. Junior synonym of brevicornis: Brown & Kempf, 1960: 215.

Worker
Brown and Kempf (1960) - TL 1.7-1.8, HL 0.42-0.46, HW 0.46-0.50 (CI 109-110), scape L 0.26-0.27, greatest diameter of eye ca. 0.02, WL 0.46-0.47 mm; based on 7 workers from New Guinea and New Britain.

Differs from other members of its group in its smaller size and in shape of alitrunk with its abruptly sloping concave dorsal face of propodeum and small subrectangular propodeal teeth. Also the following distinctive characters:

1. Clypeus traversed by a distinct, arcuate carina, separating a large, concave anterior part (covered with small squamiform hairs and opaque) and a small, feebly convex, triangular posterior part (which is nearly smooth, naked, weakly shining). In this feature, surprisingly, brevicornis resembles Eurhopalothrix clypeata of the New World (q. v.).

2. The arcuate row of 8 large specialized hairs stretching across the vertex between the eyes stands upon a feeble carina that follows the same course. Sometimes a faint trace of such a carina may be seen in other species of the genus, and it appears to be a homologue of the similarly placed carina in Octostruma rugifera, Octostruma rugiferoides, and some of the Rhopalothrix species.

3. Erect specialized hairs short and thick, clavate; 16 on cephalic dorsum; 1 pair straddling mesonotum, in most specimens missing and possibly rubbed off; first gastric tergite with 3 pairs, forming a double longitudinal row, and outside of third (posterior) pair are two more hairs, so that a transverse row of 4 is formed near the posterior edge of the segment. Both petiole and postpetiole lack larger specialized hairs entirely.

4. Petiolar node small and rather rounded above as seen from the side; as seen from above, node transverse, with rounded sides and feebly concave anterior border. Postpetiolar node about twice as wide as petiolar node, and very nearly three times as wide as long, 3/4 as wide as gaster.

5. Ground pilosity of appressed and subappressed hairs well developed on head (except for indistinct "bald area" on verticocciput), mandibles, scapes, promesonotum, legs, both nodes and gastric dorsum. Color medium ferruginous.

Queen
Brown and Kempf (1960) - Female, dealate: TL 2.3, HL 0.52, HW 0.56 (CI 108), scape L 0.31, greatest diameter of eye ca. 0.12, WL 0.62 mm. With the usual differences of caste. Dorsolateral margins of rnesonoturn with 6 short, inconspicuous, subreclinate clavate hairs. Color as in worker.