Strumigenys sylvaini

Identification
Fisher (2000) - One of the most widely distributed member of the dexis-group in the rainforest region of Madagascar. Distinguished from other members of the sylvaini-complex by having: 1 Erect short simple hairs present on dorsal surfaces of head, alitrunk, waist segments and first gastral tergite. 2 Postpetiole disc reticulate-punctate with feeble longitudinal rugulae. 3 First gastral tergite with standing hairs present between the apical and basal rows.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  sylvaini. Strumigenys silvaini Fisher, in Bolton, 2000: 644, fig. 388 (w.q.) MADAGASCAR.

Worker
Holotype. TL 2.0, HL 0.65, HW 0.56, CI 87, ML 0.19, MI 30, SL 0.30, SI 54, PW 0.38, AL 0.71. Characters of sylvaini-complex. Entirety of head blanketed with fine, dense reticulate-punctate sculpture, opaque everywhere. Dorsum of head without scale-like hairs that are similar in size to those on the fringing rows. Instead the head dorsally with sparse, minute and inconspicuous decumbent to appressed spatulate hairs, and with a row of 4 short erect hairs close to the occipital margin. Eye with 4-5 ommatidia in the longest row. Dorsal alitrunk, petiole node, and postpetiole disc finely reticulate-punctate, the postpetiole disc with feeble longitudinal rugulae. Pleurae smooth and shining. Short standing hairs present as follows: mesonotum with a single pair, 1 pair posterodorsally on the petiole node, 2 pairs posterodorsally on the postpetiole, transverse rows of hairs present between a basal and an apical row on the first gastral tergite. Lamella of propodeum narrow below the triangular propodeal spines, leaving most of the spine length free. Petiole node in dorsal view broader than long. Disc of postpetiole in dorsal view not completely surrounded by spongiform tissue, the anterolateral angles and anterior halves of the sides free. Basigastral costulae short but well developed and conspicuous.

Paratypes. TL 1.6-2.0, HL 0.60-0.65, HW 0.55-0.56, CI 86-91, ML 0.18-0.19, MI 29-30, SL 0.28-0.29, SI 51-53, PW 0.34-0.37, AL 0.67-72 (4 measured) As with holotype.

Measurements of this material extends the range shown by the type-series: HL 0.59-0.67, HW 0.52 - 0.57, CI 85-88, ML 0.18-0.19, MI 28-31.

Type Material
Holotype worker, Madagascar: 38 km. S Ambalavao, Res. Andringitra 22°12'S, 46°58'E, 1680 m., 24.x.1993, ex root mat, montane rainforest #827-2 (B. L. Fisher).

Paratypes. 1 worker and 1 queen (dealate) with same data as holotype; 3 workers with same data as holotype but 23.x.1993 #830 (50)-3, #830 (36)-8, and #830 (40)-5.