Leptogenys cracens

Identification
Lattke (2011) - Head elongate in full-face view; compound eye small, not more than 3 ommatidia in length, distance from ocular midpoint to mandibular insertion greater than that from eye to mid-distance of lateral cephalic margin, mandible subtriangular, basal margin with convex lobe basad, row of 4 setae present next to base of median lobe; petiole pedunculate in lateral view, peduncle half as long as node length; node subquadrate; constriction between abdominal segments III and IV strongly marked, with longitudinal striae.

A very singular species on account of the pedunculate petiole (the only New World species with such a petiole), mandibular structure, slender clypeal lobe and the strong constrictions at the metanotal groove as well as between abdominal segments III and IV.

Distribution
This taxon is known from southeastern Mexico.

Castes
Queen, male. Unknown.

Nomenclature

 *  cracens. Leptogenys cracens Lattke, 2011: 228, fig. 82 (w.) MEXICO.

Worker
Metrics, holotype: HL 1.12; HW 0.68; ML 0.52; EL 0.08; SL 1.30; PW 0.60; WL 1.70; PH 0.66; PL 0.80; DPW 0.40 mm. CI 0.61; MI 0.76; OI 0.12; SI 1.91; LPI 0.83; DPI 0.50.

Head elongate in full-face view, wider anterad than posterad, lateral cephalic margin mostly straight to weakly convex, posterior margin weakly convex, vertexal carina well developed, narrow, visible along all of posterior cephalic margin; median clypeal lobe slender, basal lateral margin concave, apex pointed, without setae, with 2 preapical long hairs; lateral clypeal lobe narrow, projecting little anterad. Compound eye small, not more than 3 ommatidia in length, placed laterally on head, distance from ocular midpoint to mandibular insertion greater than that from eye to mid-distance of lateral cephalic margin, eye in dorsal cephalic view weakly convex. Cephalic dorsum mostly smooth and shining except for scattered piligerous punctulae. Scape surpasses posterior cephalic border by over one-third its length, lengths of antennal segments II & IV more than twice respective apical widths, each segment wider apicad than basad, lengths of segments II & IV each more than half that of segment III, length of segment III 3 × its apical width. Scape mostly smooth and shining with scattered punctae, no appressed pubescence, with subdecumbent hairs. Mandible subtriangular, basal margin convex with row of 4 setae next to base of median lobe, each seta originating on mandibular dorsum, close to basal margin; masticatory margin edentate except for apical tooth, mandibular dorsum mostly smooth and shining except for scattered piligerous punctae, lateral margin convex.

Mesosoma with broad and well-impressed metanotal groove in lateral view, mesosoma appearing constricted at groove; promesonotal margin continously convex, dorsal propodeal margin weakly convex, more than 2 × length of declivitous margin, declivitous margin broadly convex, propodeal tooth triangular, pointed. Mesosomal side mostly smooth and shining except for irregular imbrications on posterior metapleuron, anteroventral margin of mesopleuron and ventral area with fine striate, mesometapleural suture well impressed, scrobiculate; metapleural-propodeal suture absent, mesopleuron subrectangular, propodeal spiracle broadly elliptical, facing posterolaterad. Mesonotum subquadrate, metanotal suture scrobiculate.

Petiole with anterior peduncle half as long as node length; node in lateral view subquadrate, anterior margin straight, slightly under half length of posterior margin; node highest just posterad of mid-length; dorsal margin broadly convex anterad, more convex posterad; posterior margin straight, inclined. Subpetiolar process subrectangular, posterior margin longer than anterior margin. Node in dorsal view longer than wide, anterior margin convex, width of anterior margin more than half the width of posterior margin, lateral margin broadly convex. Cross-section of node V-shaped, with convex lateral margins.

Anterior margin of abdominal segment III convex in lateral view, with anterior margin overhanging base, dorsal margin convex, constriction between abdominal segments III and IV strongly marked, longitudinally striate on both tergite and sternite, gaster widening posterad of constriction before narrowing again; stridulitrum present on pretergite of abdominal segment IV. Gaster mostly smooth and shining with scattered piligerous punctae and punctulae. Procoxa in lateral view with sparse transverse strigae; tibiae without apical setae; legs relatively long. Head and body without pubescence, only scattered pilosity. Body mostly brown; mandibles, antennae, legs and gastral apex ferruginous brown.

Type Material
Holotype worker. Mexico, Oaxaca, Grutas de Monteflor, 6 km N Valle Nacional, 28.xii.1973, J. Reddell, D. & M. McKenzie, S. Murphy leg. One worker deposited in the.

Valle Nacional is located at 17°46′N 96°18′W, and a cursory exploration on a map of points roughly 6 km north of Valle Nacional show altitudes of 300 – 900 m.

Etymology
The species name alludes to the slender and strikingly gorgeous aspect of the ant. It is Latin for graceful.