Strumigenys rubigus

Known from the type worker, found in a rainforest rotten-log.

Identification
Bolton (2000) - A member of the scotti complex in the Strumigenys scotti-group. S. rubigus is distinguished from other species in the scotti-complex which have the dorsum of petiole node reticulate-punctate by having the following combination of characters: 1 Mesonotum with only a single pair of erect hairs, located at anterior margin; shorter decumbent hairs may be present posterior to this pair. 2 In full-face view hairs on upper scrobe margin decumbent and sharply bent at basal third, not projecting well beyond the scrobe margin. 3 Anterior half of first gastral sternite with numerous short suberect hairs.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  rubigus. Strumigenys rubigus Fisher, in Bolton, 2000: 693 (w.) MADAGASCAR.

Worker
Holotype. TL 2.9, HL 0.63, HW 0.48, CI 76, ML 0.32, MI 50, SL 0.40, SI 83, PW 0.34, AL 0.7l. Characters of scotti-complex. Mandibles in full-face view with outer margins shallowly and evenly convex, the width gradually decreasing from near the base to the apicodorsal tooth. Upper scrobe margin evenly and shallowly convex in full-face view, not bordered by a rim or flange, the eyes visible. Maximum diameter of eye slightly smaller than maximum width of scape, with 3-4 ommatidia in longest row. Scape short and stout, shallowly and gently curved; hairs on leading edge spatulate or spoon-shaped. Cephalic dorsum densely clothed with curved narrow spatulate to spoon-shaped ground-pilosity, the upper scrobe margin fringed with hairs which are the same shape and size as those on the dorsum. Pronotal humeral hair flagellate hair (absent on left humerus of holotype). Mesonotum with 1 pair of erect clavate hairs, located at anterior margin; shorter hairs which are curved toward the midline present posterior to this pair. Propodeum with 2 pairs of short, fine, posteriorly curved hairs immediately anterior of propodeal spines. Dorsal alitrunk with ground-pilosity as on head. Dorsum of alitrunk in outline very shallowly convex anteriorly and more or less flat posteriorly; posterior portion of mesonotum only slightly depressed below the anterior margin of propodeum. Anterior mesonotum without a carina above mesothoracic spiracle. Propodeal tooth broadly triangular, lamellate, pointed apically, and subtended by a moderate lamella. Alitrunk dorsum densely reticulate-punctate. Side of alitrunk mostly with punctate sculpture, except for katepisternum which is smooth and shiny. Postpetiole disc smooth and shining. In profile the petiole with a straight ventral spongiform strip that is slightly less deep than maximum diameter of eye. Postpetiole with moderately developed ventral spongiform lobes. Basigastral costulae arising on each side of a narrow, central clear area. Dorsal surfaces of petiole, postpetiole and gaster with standing clavate to remiform hairs. First gastral sternite, including anterior half, with numerous short suberect filiform hairs. Colour light brown.

Type Material
Holotype worker, Madagascar: Provo Toamasina, F.C. Andrianantantely, 18°41.7'S, 48°48. 8'E, 530 m., 4-10.xii.1998, ex rotten log, rainforest, #49-2 (H. J. Ratsirarson).

References based on Global Ant Biodiversity Informatics

 * Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
 * Fisher B. L. 2003. Formicidae, ants. Pp. 811-819 in: Goodman, S. M.; Benstead, J. P. (eds.) 2003. The natural history of Madagascar. Chicago: University of Chicago Press, xxi + 1709 pp.