Strumigenys minuscula

Identification
Bolton (2000) - A member of the Strumigenys lilloana-group. When Kempf (1962) first described this small species he placed it in the splendens-group (then the genus Gymnomyrmex), but with some hesitation. In all splendens-group species the basal lamella of the mandible is very long and narrow, usually at least equal in length to the tooth row and sometimes longer, the alitrunk is long and low, and the petiole node is distinctly longer than broad in dorsal view. These characters definitely do not apply to minuscula which has a short high basal lamella, short compact alitrunk and a petiole node that is much broader than long. Direct comparison of the holotypes implies that minuscula is related to Strumigenys lilloana, with the common characterisation tabulated above. If this interpretation is correct it follows that the full-face heart-shaped head of lilloana is rather more specialised than that of minuscula, but the latter has specialised its antennomere count by reduction from 6 to 4.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil.

Nomenclature

 *  minuscula. Gymnomyrmex minusculus Kempf, 1962b: 24, figs. 22-24 (w.) BRAZIL. Combination in Pyramica: Bolton, 1999: 1672; in Strumigenys: Baroni Urbani & De Andrade, 2007: 124. See also: Bolton, 2000: 202.

Worker
Bolton (2000) - TL 1.6, HL 0.43, HW 0.39, CI 91, ML 0.09, MI 22, SL 0.16, SI 41, PW 0.24, AL 0.43. This very small species is currently one of only two known Neotropical species with 4 antennal segments (the other is simulans). Extreme anterior portion of preocular carina visible in full-face view. Also in this view the head with the upper scrobe margin markedly sinuate: margin shallowly concave behind level of frontal lobe, expanding latterally behind level of second fenestra into a bluntly convex lobe, then becoming concave again until close to the scrobe apex where it again becomes convex and grades into the lateral margin of the occipital lobe. Eye with only 4 ommatidia in total. Dorsum of head hairless except for minute scattered appressed pubescence that is difficult to see. Dorsolateral margination of pronotum, and pronotal dorsum, hairless behind humeral angles; mesonotum with a single pair of short erect hairs. Dorsal surfaces of waist Segments and gaster with a number of short erect simple hairs. Sculpture absent except for basigastral costulae that arise across the entire width of the sc1erite. In dorsal view the lateral lobes of both the petiole and postpetiole are laminate rather than spongiform; in profile the ventral lobes of both segments are spongiform.

Type Material
Bolton (2000) - Holotype worker, BRAZIL: Santa Catarina, Chapeco, vii.1960 (F. Plaumann) [examined].