Leptogenys guianensis

Identification
Lattke (2011) - Head elongate, eyes flattened placed slightly anterad of lateral cephalic margin mid-distance; propodeal dorsal margin straight in lateral view, dorsal margin of propodeal tooth serrate in lateral view; node trapezoid in dorsal view, anterior and posterior margins parallel, anterior margin half the width of posterior margin.

A member of the pusilla species group.

Distribution
This taxon was described from Guyana. It is known from French Guiana – northern Brazil.

Castes
Queen, male. Unknown.

Nomenclature

 *  guianensis. Leptogenys (Lobopelta) guianensis Wheeler, W.M. 1923d: 12, fig. 5 (w.) GUYANA. See also: Lattke, 2011: 192.

Worker
Lattke (2011) - Metrics (n = 3) : HL 0.89 – 0.97; HW 0.58 – 0.62; ML 0.43 – 0.45; EL 0.12 – 0.14; SL 0.80 – 0.87; PW 0.52 – 0.55; WL 1.32 – 1.40; PH 0.52 – 0.53; PL 0.45 – 0.50; DPW 0.33–0.38 mm. CI 0.64–0.66; MI 0.70–0.74; OI 0.20 – 0.23; SI 1.37 – 1.41; LPI 1.07 – 1.19; DPI 0.74 – 0.81.

Head rectangular in full-face view, slightly wider anterad than posterad; posterior margin straight with vertexal carina visible most of length; lateral cephalic margin mostly broadly convex. Anterior clypeal margin evenly converges anterad to triangular median lobe, apex pointed to slightly blunt; clypeus longitudinally striate medially, laterally with transverse striae. Scape surpasses posterior cephalic border by less than one-fourth its length; densely punctulate; antennal segment III longer than either segments II or IV; segments II and IV each over half the length of III; segment III twice longer than wide. Cephalic dorsum mostly smooth and shining, with sparse piligerous punctulae. Mandibles shut tight against clypeus; elongate, parallel width, basal margin convex, external margin concave; dorsum with sparse punctulae and weak fine, parallel striae; basal angle obtuse, bluntly angular, apical tooth broad, basal margin with two stout hairs; PF: 4,4. Eye flat, situated laterally with slight medial tendency.

Mesosoma with broadly convex promesonotal margin in lateral view, posterior mesonotal margin drops into metanotal groove, dorsal propodeal margin mostly straight, curving onto declivity, propodeal tooth broadly triangular. Mesosoma mostly smooth and shining, with weak, oblique striae on ventral mesopleuron, propodeal spiracle round; mesometapleural suture well impressed, scrobiculate; propodeal spiracle elongate, posterolaterally facing. Mesonotum wider than long in dorsal view, anterior margin curved, posterior margin straight, metanotal groove scrobiculate; propodeal declivity with transverse striae. Petiole subquadrate in lateral view, anterior margin almost half length of posterior margin, dorsal margin mostly sloped with rounded apex, node highest posterad of mid-length; posterior margin mostly straight. Node trapezoid in dorsal view, anterior and posterior margins parallel, anterior margin half the width of posterior margin, gaster smooth and shining with sparse piligerous punctulae. Procoxa smooth and shining laterally, body with sparse standing pilosity, no appressed pilosity. Mandible, clypeus, antennae, and legs light brown; head, mesosoma, petiole and gaster ferruginous brown; apex of protarsus with slender seta; dorsal surface of metacoxa with low posterior lobe. Constriction between abdominal segments III and IV well marked.

Type Material
Syntype workers: Guiana (= British Guiana), Dunoon, 2.viii.1914, Cat. No. 1 – 2, 20508 (F.M. Gaige) [examined].

The syntypes are two point-mounted workers on the same pin: MCZ Cotype 1 – 2, 20508. Wheeler’s (1923) description is quite detailed and I agree with all save the extension of the scape beyond the posterior cephalic border, which is one-third according to him. The type series specimens are paler in color than the specimens from Suriname or Brazil.

Additional References

 * Lattke, J.E. 2011. Revision of the New World species of the genus Leptogenys Roger (Insecta: Hymenoptera: Formicidae: Ponerinae). Arthropod Systematics & Phylogeny 69:127-264.