Strumigenys emarginata

Identification
Bolton (1983) - Within its species-group emarginata stands very much alone, lacking the pilosity and other characters of the various species-complexes discussed under the species-group diagnosis, but possessing an elongate narrow head, long scapes and a basally indented first gastral tergite coupled with the largest eyes known for a member of this genus in the Afrotropical region.

Despite the wide range of the species it shows relatively little variation, the only notable changes occurring in the form of the alitrunk pilosity as discussed above. Brown (1953a: 126) first drew attention to this but noted that, even though his material was sparse, intergrades between the forms were apparently present. This study has confirmed that alitrunk pilosity is by no means stable in emarginata and, like Brown, I am of the opinion that the differences observed only represent variation between populations and are not significant at species-level.

Distribution based on Regional Taxon Lists
Afrotropical Region: Angola, Burundi, Ghana, Ivory Coast, South Africa, Togo, Zimbabwe.

Nomenclature

 *  emarginata. Strumigenys emarginata Mayr, 1901b: 26 (w.) SOUTH AFRICA. Combination in S. (Trichoscapa): Santschi, 1913b: 257; in S. (Cephaloxys): Wheeler, W.M. 1922a: 919; Emery, 1924d: 324; in Smithistruma: Brown, 1948e: 105; in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 119. See also: Brown, 1953g: 126; Bolton, 1983: 291; Bolton, 2000: 301.

Worker
Bolton (1983) - TL 2.4-2.8, HL 0.64-0.70, HW 0.39-0.42, CI 58-64, ML 0.11-0.12, MI 16-19, SL 0.29-0.32, SI 72-80, PW 0.24-0.28, AL 0.62-0.72 (18 measured).

Mandibles with a high truncated triangular basal lamella (concealed by clypeus when mandibles are closed), followed without a diastema by a row of 5 relatively large teeth, 2 slightly smaller teeth and 4 small denticles before the apical tooth. Anterior clypeal margin in full-face view varying from almost transverse to evenly shallowly concave. Lateral margins of clypeus slightly convergent anteriorly, the anterolateral clypeal angles bluntly rounded. Anterior clypeal margin fringed by a series (usually of 6-8) broad scale-like hairs, the lateral margins and corners with an unbroken sequence of long fringing hairs which are flattened to spoon-shaped and which are curved anteriorly on the sides and medially on the anterolateral corners. Dorsum of clypeus and of head behind clypeus with numerous spoon-shaped curved hairs which appear scale-like in full-face view. Sometimes the occipital region with a few simple curved hairs present but these variable in number and degree of development; flagellate hairs never developed. With the head in full-face view the upper scrobe margins and occipital lobes laterally fringed with anteriorly curved spoon-shaped hairs, the head long and narrow (CI < 65) and with the eyes plainly visible, projecting beyond the level of the upper scrobe margins. Eyes larger than in any other other known Afrotropical species, their maximum diameter 0.21-0.25 X HW, greater than the maximum width of the scape. Scapes long (SI >70), narrow basally, shallowly curved at about the basal third and broadest just distal to this where the leading edge is bluntly subangulate. Leading edges of scapes with projecting flattened to spoon-shaped strong hairs. With the head in profile the dorsum very shallowly impressed between clypeus and vertex, highest at the vertex and sloping down posteriorly to the occipital margin. Dorsum of head finely and densely reticulate-punctulate to granular everywhere. With the alitrunk in profile the central portion of the mesonotum extremely feebly impressed. The metanotal groove not impressed but sometimes represented as a line. Propodeal teeth long and narrow, often slightly upcurved and sometimes weakly sinuate along their length. Infradental lamellae narrow and inconspicuous down the propodeal declivity. Sides of alitrunk not marginate, the pronotal dorsum without a median longitudinal ridge or carina, the pronotal humeri evenly rounded. Pilosity of dorsal alitrunk variable, usually with curved spoon-shaped hairs on pronotum and anterior mesonotum but behind this the hairs longer and finer, subspatulate to cylindrical and simple, and often with one or two pairs suberect to erect. Variation from this more or less median position is shown on the one hand in samples where all the hairs are spoon-shaped and merely vary in size (becoming larger posteriorly), there being no subspatulate or simple hairs developed; and on the other hand by the suppression of the spoon-shaped hairs and their replacement everywhere by simple suberect to erect pilosity. Flagellate hairs never present. Pronotal dorsum very finely and faintly striate, this sculpture sometimes virtually effaced. Mesonotum and usually also propodeal dorsum finely punctulate; sides of alitrunk punctulate. Spongiform appendages of petiole and postpetiole massively developed in profile. In dorsal view the petiole with a spongiform strip on its posterior margin which is strongest posterolaterally. Anterior margin of postpetiole in dorsal view with a spongiform strip but the sides without. The broadly convex posterior margin of the postpetiole with spongiform tissue very broadly developed at the sides but strongly indented or even interrupted medially, usually the posterior margin of the spongiform material touching the margin of the postpetiolar disc centrally. Petiole dorsum very faintly punctulate to smooth, the disc of the postpetiole always unsculptured and smooth. Dorsal surfaces of petiole, postpetiole and first gastral tergite with elongate simple curved hairs present. First gastral tergite impressed mediobasally, usually sharply so, the impressed area usually including both the central portion of the basal lamellar band of the tergite and the tergal area immediately behind it. Basigastral costulae absent from the impressed area, radiating from each side of it; gaster otherwise unsculptured. Colour yellow to medium brown, sometimes the gaster distinctly darker than the head and alitrunk.

Type Material
Bolton (1983) - Syntype workers, SOUTH AFRICA: Port Elizabeth (H. Brauns) [examined].