Strumigenys placora

Very little information is available about this rather rare species of Pyramica.

Distribution based on Regional Taxon Lists
Afrotropical Region: Cameroun, Equatorial Guinea, Gabon.

Biology
Found in the leaf litter. Gonzalo Girabet (Harvard University) collected a nice series of workers from Equatorial Guinea.

Castes
Queens and males are unknown.

Nomenclature

 *  placora. Smithistruma placora Bolton, 1983: 308 (w.) CAMEROUN. Combination in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 126. See also: Bolton, 2000: 340.

Description
HOLOTYPE WORKER. TL 2.1, HL 0.58, HW O.39, CI 67, ML 0.04, MI 7, SL 0.28, SI 72, PW 0.27, AL 0.58.

Dentition of mandible (from a paratype) as described for Strumigenys malaplax. With the head in full-face view the anterior clypeal margin very shallowly concave. Sides of clypeus irregular and feebly convex, somewhat convergent anteriorly and with rounded anterolateral angles. Lateral margins of clypeus in full-face view with numerous projecting hairs; a lower series of more slender hairs present which are curved anteriorly and are densest on the posterior halves of the margins, the more anteriorly placed members of this series of slender hairs may be upcurved apically. Above these finer hairs is a series of much longer stouter cylindrical hairs which project anterolau:rally, are curved upwards or upwards and backward in the apical half to one-third of their length, and which are feebly clavate apically. The anterior clypeal margin with a few pairs of weakly clavate very short hairs which are directed towards the midline. Sides of head in full-face view irregular, with projecting long hairs which are stoutest and most rigid anteriorly on the upper scrobe margins but which become finer and more flexuous posteriorly on the sides and are weakly flagellate on the posterior curves of the occipital lobes. With the head in profile the clypeal dorsum with a shallow median concavity which lacks hairs. In front of this the anterior clypeal convexity is equipped with numerous short stout weakly clavate hairs which are directed anterodorsally from their bases but which are then curved so that their apieces point vertically or even posteriorly; the more anteriorly situated members of this group of hairs are shorter than those nearest the median concavity. Behind the median clypeal concavity is a single transverse row of longer sinuate weakly clavate hairs whose apices tend to point weakly forwards. Behind these, at the level of the frontal lobes are similarly constructed but shorter hairs, about half the length of the posterior clypeal row or slightly more. Dorsum of head behind clypeus with fine simple short groundpilosity which is closely applied to the surface and strongly curved anteriorly, and With numerous very long specialized hairs which are arranged roughly in arched-transverse rows. The anteriormost specialized row contains the stoutest most rigid hairs, which are slightly curved anteriorly and at least twice longer than the longest hairs on the clypeal dorsum. The more posterior rows are no shorter but become progressively finer and more flexuous; those behind the vertex are feebly flagellate. Scape weakly bent at its basal third and broadest just distal to this, the leading edge and dorsal surface with curved simple projecting hairs. Maximum diameter of eye 0•15 x HW. Dorsum of head densely reticulate-rugose. Pronotum not marginate laterally, without a median longitudinal ridge or carina. Alitrunk in profile lacking a metanotal groove or impression. Propodeal teeth narrowly triangular and subtended by a narrow evenly concave infradental lamella. Sides of pronotum and propodeum irregularly rugulose, the pleurae punctate. Promesonotal dorsum longitudinally rugose with weakly punctulate interspaces. Propodeal dorsum densely punctate with only vestiges of fine rugulae, the declivity smooth. Dorsum of petiole node irregularly rugose, the postpetiolar disc smooth and shining. First gastral tergite with dense conspicuous basal costulae. Dorsal surfaces of pronotum, mesonotum, petiole, postpetiole and gaster with numerous long fine flagellate hairs. Spongiform appendages of pedicel segments massively developed in profile. In dorsal view the petiole node with a broad posterior spongiform strip which is concave posteromedially. Postpetiole disc completely surrounded by spongiform material, the margin of the posterior spongiform strip sharply indented medially. Spongiform band traversing base of first gastral tergite thick and ruff-like. Colour medium brown, the gaster blackish brown.

PARATYPE WORKERS. TL 2.0-2.1, HL 0.56-0.60, HW 0.36-0.38, CI 63-66, ML 0.04-0.05, MI 7-9, SL 0.24-0.28, SI 68-74, PW 0.24-0.27, AL 0.52-0.58 (3 measured).

As holotype but maximum diameter of eye 0.14--0.16xHW.

Holotype worker, Cameroun: Nkoemvon, 2.xi.1980, N49 (D. Jackson) (BMNH).

Paratypes. Cameroun: 2 workers with same data as holotype but 2.iii.1980; 1 worker with same data but 12.x.1980, N45 (MHN).

Among the species of the weberi-complex of this group, as characterized by their unsculptured postpetiolar discs, placora is isolated by its remarkable cephalic pilosity and lack of an impressed metanotal groove. The closest relatives of placora, Strumigenys fenkara, Strumigenys tolomyla and Strumigenys synkara, are discussed under the last name.

Additional References

 * Baroni Urbani, C. & De Andrade, M.L. 2007. The ant tribe Dacetini: limits and constituent genera, with descriptions of new species. Annali del Museo Civico di Storia Naturale “G. Doria” 99: 1-191.
 * [[Media:Bolton 1983.pdf|Bolton, B. 1983. The Afrotropical dacetine ants (Formicidae). Bull. Br. Mus. (Nat. Hist.) Entomol. 46: 267-416 PDF]]