Strumigenys barylonga

Identification
Bolton (2000) - The closest relative of this species is Strumigenys kraepelini, itself an attenuated ant with long scapes and narrow head, but not as markedly so as in barylonga. The petiole node of kraepelini has a well defined anterior face that forms a marked change of slope between the peduncle and the dorsum. In contrast the peduncle of barylonga forms a single evenly sloping surface that extends to the anterodorsal angle of the node, leaving the node without a differentiated anterior face.

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

Nomenclature

 *  barylonga. Strumigenys barylonga Bolton, 2000: 879, figs. 472, 511 (w.) INDONESIA (Sumatra).

Worker
Holotype. TL 3.4, HL 0.99, HW 0.48, CI 48, ML 0.43, MI 43, SL 0.70, SI 146, PW 0.29, AL 0.96. Characters of the feae-complex. Extremely slender attenuated species with very long scapes and legs (maximum length of hind femur 0.90) and very narrow head. Preapical tooth short-triangular, its length less than half the width of mandible at point where tooth arises. Outer and inner margins of mandible in full-face view straight from close to base to level of preapical tooth. With head in full-face view anteriormost point of eye is located just posterior to 0.50 X HL (behind midlength of head). Upper scrobe margin with two freely laterally projecting long flagellate hairs. Cephalic dorsum with 4 erect flagellate hairs along the occipital margin, a similar pair present at highest point of vertex. Preocular notch absent, ventrolateral margin of head extremely shallowly evenly concave immediately in front of eye and straight anteriorly. Maximum diameter of eye slightly greater than maximum width of scape. Pronotal humeral hair flagellate; pronotal dorsum with a smooth shining median patch, otherwise dorsal alitrunk reticulate-punctate. Pronotal dorsum without standing hairs, mesonotum with 2 pairs of erect flagellate hairs. Dorsal surfaces of waist segments and first gastral tergite with long flagellate hairs. Pleurae and side of propodeum smooth; in profile the mesothorax long and strongly constricted in its anterior half. One or two long fine erect flagellate hairs present on the dorsal (outer) surface of the hind basitarsus and another 1-2 on the hind tibia; similar pilosity present on the other legs. Petiole in profile long and low, without a differentiated anterior face. What would be the anterior face of the node is merely an even continuation of the slope of the peduncle, that continues to the anterodorsal angle of the node. Dorsum of node long and low, shallowly convex. In dorsal view petiole node longer than broad, reticulate-punctate; disc of postpetiole narrow and smooth. Basigastral costulae much shorter than disc of postpetiole.

The non-paratypic material consists of a single worker whose dimensions are HL 1.01, HW 0.44, CI 44, ML 0.44, MI 44, SL 0.70, SI 159. It resembles the holotype very closely but its preapical tooth is very reduced, much smaller than in the holotype, and its petiole node has a very short, but distinct, anterior face in profile. With only two specimens available it is impossible to comment on the species-rank significance of this variation, but as it is small I have opted to retain both as a single species.

Type Material
Holotype worker, Indonesia: N Sumatra, Brastagi, 1500 m., 6.vi.1984 (Rougemont).