Calyptomyrmex sabahensis

This species has been encountered a number of times in extreme north-eastern Borneo, always in rainforest leaf litter. Nothing further is known of its biology.

Identification
Hairs on head and body thin (essentially the same width along entire length, or only slightly and gradually expanded distally, and with blunt tips), gaster weakly (and sometimes indistinctly) punctate, propodeum armed with short, broad angles; setae on leading edge of scape long, about as long as scape width, legs rugo-reticulate. This combination of characters will separate this species from all others in the region where it occurs.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia.

Nomenclature

 *  sabahensis. Calyptomyrmex sabahensis Shattuck, 2011: 21, fig. 15 (w.) BORNEO.

Holotype worker from Quoin Hill, Tawau, Sabah, Malaysia, 16–19 June 1968, R. W. Taylor, rainforest, leafmould (, ANIC32-05 1676). Paratypes: 20 workers, same data as holotype (4 workers, ANIC32-051672 (3 in, 1 in ); 2 workers, ANIC32-051673; 8 workers, ANIC32-051674 (7 in , 1 in ); 4 workers, ANIC 32-05 1675; 2 workers, ANIC32-053425).

Description
Worker description. Mandibles striate basally, essentially smooth apically. Eyes small, with 2–3 ommatidia in greatest diameter. Propodeum in lateral view armed with short, broad angles. Propodeal lobes thin anteriorly, thickened posteriorly. Node of petiole in profile slightly higher and slightly larger than that of postpetiole. In dorsal view the petiolar node narrower than the postpetiolar node. Head indistinctly rugose, the rugae longitudinal anteriorly and forming an indistinct network posteriorly, with the entire surface finely but distinctly punctate. Mesosoma and petiolar and postpetiolar nodes with irregular, wavy rugae superimposed over an indistinctly punctate background. Gaster finely and indistinctly sculptured and with a matte appearance. Hairs on head and body erect, uniform in diameter and with sharp or blunt tips. Clypeal fork with slightly enlarged and thin hairs, all hairs approximately the same length. Colour red-brown, antennae and legs slightly lighter.

Measurements. Worker (n = 8) - CFW 0.12–0.14; CI 98–104; HL 0.73–0.79; HW 0.74–0.81; ML 0.71–0.79; MTL 0.32–0.36; PetI 130–147; PetL 0.18–0.21; PetW 0.24–0.30; PronW 0.50–0.53; SI 5 1–54; SL 0.40–0.43.