Strumigenys longinoi

Identification
Bolton (2000) - Easily the largest species yet discovered in the group (HL 0.74-0.84, as opposed to a range of HL 0.44-0.66 in all other species). This relatively large size, combined with its extremely flattened head and total lack of standing hairs, renders longinoi immediately recognisable within the group.

Distribution based on Regional Taxon Lists
Neotropical Region: Costa Rica.

Nomenclature

 *  longinoi. Pyramica longinoi Bolton, 2000: 173, fig. 128 (w.q.) COSTA RICA. Combination in Strumigenys: Baroni Urbani & De Andrade, 2007: 122

Worker
Holotype. TL 2.9, HL 0.80, HW 0.69, CI 86, ML 0.16, MI 20, SL 0.34, SI 49, PW 0.32, AL 0.80. Outer margins of fully closed mandibles evenly but conspicuously convex in full-face view. Mandible with a basal row of 7 similar-sized stout conical teeth that immediately follow the basal lamella; tooth 8 slightly smaller than these and teeth 9 and 10 (apical) smaller still. Apex of basal lamella (in dissected paratype) level with apices of teeth 1-5, its basal length greater than the base length of teeth 1 + 2. Maximum depth of extremely flattened head 0.41 X HW. Eye with 4 ommatidia in longest row; side of head in front of eye punctulate but remainder of scrobe smooth. Pronotum bluntly angulate dorsolaterally, the mesonotum and propodeum somewhat more sharply marginate and the latter with a transverse arched carina at top of declivity between the spines. Propodeal spines elongate, acutely triangular and broad-based. Petiole and postpetiole without ventral spongiform lobes; base of first gastral sternite without trace of spongiform tissue. Petiole node in dorsal view longer than broad and with a minute rounded non-spongiform lobe on each side. Lateral lobes of the U -shaped postpetiole are aliform and sclerotised, not spongiform. Base of first gastral sternite flattened or even slightly concave on each side of the midline, stemite overhung by tergite laterobasally. Projecting hairs absent from upper scrobe margins and pronotal humeri. All dorsal and dorsolateral surfaces of head and alitrunk lack standing or projecting hairs of any form. Only minute appressed pubescence present, densest on clypeus where it is directed anteromedially, much sparser on head behind clypeus and on dorsal alitrunk. Waist segments and gaster with similar minute appressed pubescence, without standing hairs dorsally. In dorsal view side of petiole with a single pair of posteriorly curved hairs that arise just in front of the tiny lateral lobes. In dorsal view head finely shagreenate peripherally but centrally smooth with scattered minute punctures. Dorsal surfaces of alitrunk and waist segments with fine superficial sculpture only. Sides of alitrunk smooth and shining except for weak sculpture around the periphery. First gastral tergite with extremely feeble but quite dense basal costulae that span the width of the sclerite and are interspersed with even finer longitudinal striolae, so that the basal third of the tergite is quite densely, though faintly and superficially, sculptured.

Paraytpe. TL 2.5-3.0, HL 0.74-0. 84, HW 0.64-0.72, CI 85-87, ML 0.15-0.16, MI 19-21, SL 0.29-0.34, SI 44-51, PW 0.30-0.35, AL 0.72-0.80 (10 measured). Maximum depth of head 0.41-0.44 X HW.

Type Material
Holotype worker, Costa Rica: Alajuela Prov., Rio Penas Blancas, 1019'N, 84°43'W, 800 m., 23.v.1990, wet forest, ex sifted leaf litter, #2701 -s (J. Longino).

Paratypes. 11 workers with same data as holotype; 1 worker with same data but 26-28.iv.1987, #1579-s; 1 worker and 1 queen (dealate) Costa Rica: Provo Limon, Res. Biol. Hitoy-Cerere. 9°40'N, 83°02'W, 500 m., 30.viii.l985, wet forest litter sample, #970-s (J. Longino) (INBIO,, , , , , and in coil. Longino).