Strumigenys actis

Identification
Bolton (2000) - A member of the chilo complex in the Strumigenys grandidieri-group. Among the Malagasy species that have the mandibular apical fork subtended by a shorter third tooth actis is easily isolated by the following characters:

1 Upper scrobe margin ends, or at least becomes extremely indistinct, at about the level of the eye; when viewed in profile, upper scrobe margin extends posteriorly across dorsal apex of vertical preocular groove of side of head; preocular groove meets and is interrupted by the upper scrobe margin before reaching the cephalic dorsum.

2 Mesonotum with 1 pair of erect hairs, on anterior margin.

3 Cephalic dorsum with a transverse row of four erect hairs immediately in front of occipital margin.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  actis. Strumigenys actis Fisher, in Bolton, 2000: 648 (w.) MADAGASCAR.

Worker
Holotype. TL 3.4, HL 0.88, HW 0.70, CI 80, ML 0.46, MI 52, SL 0.59, SI 84, PW 0.36, AL 0.85. Characters of chilo-complex. Mandibles almost straight and at full closure parallel. Apical fork of mandible subtended by a third, shorter spiniform tooth, the fork effectively 3-dentate; without intercalary teeth or denticles. Preapical teeth absent. Upper scrobe margin ends, or at least becomes extremely indistinct, at about the level of the eye; when viewed in profile upper scrobe margin extends posteriorly across dorsal apex of vertical preocular groove of side of head; preocular groove meets and is interrupted by the upper scrobe margin before reaching the cephalic dorsum. Eye large, convex, and plainly visible in full-face view. Scape long and slender, approximately straight, the leading edge with a row of slender hairs which are slightly flattened or spoon-shaped apically. Cephalic dorsum densely clothed with curved spoon-shaped ground-pilosity; the upper scrobe margin without a row of hairs. Cephalic dorsum with 4 simple standing hairs arranged in a transverse row close to the occipital margin. Dorsum of head reticulate-punctate. Mesonotum with a single pair of stout standing hairs situated on anterior margin. Propodeum with one pair of short, fine, posteriorly curved hairs immediately anterior of propodeal spines. Ground-pilosity on alitrunk as on head but sparser. With the alitrunk in profile the posterior portion of the mesonotum sharply depressed, the metanotal groove represented by a shallow impression. Pronotal humeri rounded. Lateral margin of posterior pronotum bluntly marginate. Anterior mesonotum with a narrow carina above the mesothoracic spiracle. Propodeal tooth long and slender, almost spiniform; propodeal lamella absent. Alitrunk dorsum and sides reticulate-punctate. Petiole node in dorsal view reticulate-punctate and much longer than broad. Postpetiole disc reticulate-punctate. Spongiform appendages of petiole weakly developed. Postpetiole with small but distinct lateral and ventral spongiform lobes. Basigastral costulae fine across base of gaster without a central clear area; gaster smooth and shiny where clean. Dorsal surfaces of petiole often with a pair of short posteriorly projecting hairs; postpetiole with a pair of posteriorly projecting stout hairs; gaster with stout standing hairs which are weakly swollen apically. Colour dull yellow to light medium brown.

Measurements of this material extend the range shown by the type-series: TL 3.3-3.9, HL 0.86-1.01, HW 0.65-0.86, CI 75-92, ML 0.44-0.54, MI 49-59, SL 0.56-0.70, SI 79-86, PW 0.34-0.41, AL 0.80-0.99 (9 measured).

Type Material
Holotype worker, Madagascar: 43 km. S Ambalavao, Res. Andringitra, 22°14'S, 47°00'E, 825 m., 5.x.1993, sifted litter (leaf mold rotten wood), rainforest #747 (14)-8 (B. L. Fisher).