Strumigenys lilloana

Identification
Bolton (2000) - A member of the Strumigenys lilloana-group. Only Strumigenys minuscula is also included in this group. The two separate easily as the antenna is 4-segmented, the upper scrobe margin is sinuate and the preocular carina is visible anteriorly in minuscula, whereas the antenna has the usual 6 segments, the head is heart-shaped and the preocular carina is completely concealed by the expanded frontal lobe in lilloana. In addition, in minuscula the head is narrower (CI 86), the dorsolateral margination of the pronotum is hairless behind the humeral angle, and the basigastral costulae arise across the whole width of the first gastral tergite.

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Brazil.

Nomenclature

 *  lilloana. Glamyromyrmex (Chelystruma) lilloana Brown, 1950a: 23, fig. 1 (w.) ARGENTINA. Combination in Chelystruma: Kempf, 1959d: 338; in Pyramica: Bolton, 1999: 1672; in Strumigenys: Baroni Urbani & De Andrade, 2007: 122. See also: Bolton, 2000: 201.

Worker
Bolton (2000) - TL 1.9-2.3, HL 0.54-0.56, HW 0.52-0.54, CI 93-100, ML 0.09-0.12, MI 17-22, SL 0.22-0.26, SI 42-48, PW 0.34-0.38, AL 0.50-0.54 (2 measured). The mandibles are fully closed in the few specimens available; shortage of material precludes dissection. However, on the left mandible what appears to be the anterior margin of the basal lamella is just visible in front of the anterior clypeal margin, immediately followed by the tooth row without a diastema. On the right mandible there is a distinct gap or diastema between the basal tooth and anterior clypeal margin. Upper scrobe margins in profile thick behind level of eye, the latter with 5 ommatidia in the longest row. Frontal carinae very broad in full-face view, convex and continuous with the expanded convex fronta1 lobe; the head capsule in this view, excluding the mandibles, strikingly heart-shaped. A single fenestra on each side immediately above the antennal insertion. On postpetiole the lateral lobe extensive and strongly projecting laterally, extensively overhanging the ventral lobe so that the latter is not visible in dorsal view. All waist appendages are more lamellate than spongiform. Discs of petiole and postpetiole in dorsal view both much broader than long and glassy smooth; sides of petiole node converge posteriorly. Disc of postpetiole with anterior margin transverse. Sharp dorsolateral margins of pronotum behind humeri, and lateral marginations of mesonotum, with sparse stiff simple hairs that project dorsolaterally. Petiole, postpetiole and first gastral tergite with short simple standing hairs. Head and body almost entirely unsculptured, here and there with faint superficial reticular patterning on dorsal head and alitrunk; propodeum with 2-3 arched transverse rugulae where dorsum meets declivity. Basigastral costulae present on each side of a clear median strip; longest costulae extend almost half length of tergite.

Type Material
Bolton (2000) - Holotype worker and paratype workers, ARGENTINA: Tucuman, in garden of Instituto Miguel Lillo, 20.iii.1948 (N. Kusnezov) [examined].