Leptogenys amazonica

Lattke (2010) reported: A Yasuni, Ecuador specimen was taken on the ground in an open disturbed area, and Chiruisla, Ecuador specimens were found beneath the leaf petiole of a palm (J.M. Vieira, pers. comm.).

Identification
Key to Leptogenys of the New World

Lattke (2011) - Head mostly smooth and shining in full-face view; mandible arched and well separated from clypeus, mostly semi-parallel, weakly widening apicad; mesonotum longer than wide, propodeal dorsum transversely striate; node longer than wide in dorsal view, posterior apex with a brief and bluntly pointed, dorsoposteriorly pointing spine.

A member of the unistimulosa species group. Borgmeier (1930) considered this species close to Leptogenys bohlsi, though he did not explicitly state why and simply mentioned several characters useful for separating the two. This author agrees with Borgmeier’s statement since both species are considered within the same species group, though L. amazonica might be closer to Leptogenys punctaticeps on account of the weakly developed hypostomal teeth, elongate head shape, mandibles with widening apex, and elongate petiolar node, all characters shared by both species.

Distribution
This taxon was described from Brazil. It is known from eastern Ecuador – northeastern Brazil.

Castes
Queen, male. Unknown.

Nomenclature

 *  amazonica. Leptogenys (Leptogenys) amazonica Borgmeier, 1930: 25, pl. 3, fig. 10; pl. 4, figs. 11, 12 (w.) BRAZIL. See also: Lattke, 2011: 213.

Worker
Lattke (2011) - Metrics (n =4): HL 1.21–1.27; HW 0.96– 0.99; ML 0.76 – 0.83; EL 0.28 – 0.30; SL 1.37 – 1.42; PW 0.78 – 0.81; WL 2.13 – 2.18; PH 0.83 – 0.89; PL 0.63 – 0.66; DPW 0.43–0.48 mm. CI 0.76–0.81; MI 0.77– 0.87; OI 0.28–0.32; SI 1.41–1.47; LPI 0.00–1.40; DPI 0.65 – 0.73.

Head longer than wide in full-face view, wider anterad than posterad, lateral margin broadly convex, posterior margin medially straight to broadly convex, vertexal carina visible; compound eye convex, covering about one-third of lateral cephalic margin; median clypeal lobe modest, apex oval, shorter than maximum scape width, laterally surrounded by narrow strip of translucent cuticle, apex with 3–4 setae. Lateral lobe low, convex, base of median lobe forms almost perpendicular angle with lateral lobe. Cephalic dorsal and ventral surfaces mostly smooth and shining; clypeus with weak oblique striae. Scape surpasses posterior cephalic border by about one-third its length, funicular segments longer than wide, fourth antennal segment longer than three-fourths length of third segment. Mandible elongate, arched and widely separated from clypeus; mostly semi-parallel in cephalic full-face view, modestly widening apicad; hypostomal tooth not visible in cephalic full-face view.

Promesonotal margin forms convexity in lateral view, propodeal dorsal margin forms another, very broad, convexity in lateral view; metanotal groove well impressed; propodeal declivitous margin convex, curving continously from dorsal margin, unarmed. Pronotum mostly smooth and shining, with variable amount of posterolateral longitudinal striae; mesopleuron rugulose towards dorsum, medially smooth and shining with posteroventral striae. Metapleuron and lateral propodeal face obliquely to transversely striate, metapleural-propodeal suture well impressed, broad and scrobiculate; anteroventral margin of mesopleuron bordered by low crest that forms minute triangular lobe anterad. Mesometapleural suture well impressed, pronotal dorsum and mesonotum mostly smooth and shining, mesonotum longer than wide in dorsal view; propodeal dorsum and declivity transversely striate, spiracle elongate.

Petiole with brief vertical anterior margin in lateral view, curving onto long and broadly convex dorsal margin, highest posterad, and ending in short, straight, bluntly pointed tooth; posterior petiolar margin sinuous in lateral view, concave below tooth, then convex. Ventral petiolar process shaped as rounded lobe, lateral face with longitudinal striae; node elongate in dorsal view, anterior margin slightly more than half width of posterior margin, petiolar tooth parallel-sided. Gaster smooth and shining, constriction between abdominal segments III and IV modest. Body with no applied pubescence, with sparse erect to suberect hairs. Head, mandibles, antennae, legs, and gaster colored ferruginous to orange; mesosoma and petiole ferruginous brown.

Type Material
Lattke (2011) - Holotype worker: Brazil, Amazonas, Teffe´, 1921, Cat. No. 2526 (Tastevin) (IBSP) [examined]. The holotype has a handwritten label by Borgmeier and bears the number 2526. It is in fine shape save a missing metatarsus.

Additional References

 * [[Media:Borgmeier 1930.pdf|Borgmeier, T. 1930. Duas rainhas de Eciton e algumas outras formigas brasileiras. Arch. Inst. Biol. (Sa~o Paulo) 3: 21-40 PDF]]
 * 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.