Leptogenys volcanica

The type series comes from a column of workers that were captured as they worked together to transport an isopod, the crustacean is point-mounted along with an ant on a single pin. Lattke & Longino (2009) call this species JTL-001 (cf. mexicana) in the Ants of Costa Rica website. Longino records a worker taken on a road through a pasture from Puntarenas, 1 km SW Monteverde, at 1350 m. (Lattke 2011)

Identification
Key to Leptogenys of the New World

Lattke (2011) - A member of the elongata species group. Cephalic dorsum mostly densely punctate; lateral clypeal process forms almost perpendicular angle with base of median process; eye occupies approximately one-third of lateral cephalic margin, situated laterally; metapleural-propodeal suture distinct; anteroventral mesopleural carina well developed, forming cupped rounded lobe anterad.

Castes
Queen, Male. Unknown.

Nomenclature

 *  volcanica. Leptogenys volcanica Lattke, 2011: 166, fig. 23 (w.) COSTA RICA.

The shallow depression that suggests a separation between the anepisternum and katepisternum is unusual in the genus as the mesopleuron usually appears as a single unit in workers, bearing no trace of this separation. The Panama specimens have the metapleural propodeal sutures more developed and consequently the metapleuron stands out quite distinctly, and the mesopleuron has a more irregular surface with broad swellings and depressions. The Colombian specimens have mostly smooth sculpturing with scattered punctae between and anterad of the eyes, the head has shallower and finer punctae, the mesosomal sides have more punctate areas, and the extremities are lighter colored.

Worker
Metrics, holotype (paratypes, n = 5): HL 1.04 (0.94-1.08); HW 0.71 (0.64-0.74); ML 0.61 (0.51-0.57); EL 0.20 (0.20-0.20); SL 1.21 (1.08-1.25); PW 0.64 (0.54-0.64); WL 1.65 (1.52-1.75); PH 0.67 (0.61-0.67); PL 0.57 (0.57-0.61); DPW 0.44 (0.40-0.47) mm. CI 0.68 (0.66-0.69); MI 0.86 (0.77–0.81); OI 0.29 (0.27-0.32); SI 1.71 (1.64-1.76); LPI 1.18 (0.00-1.18); DPI 0.76 (0.71-0.78).

Head sub-rectangular in full-face view, wider anterad than posterad; lateral cephalic margin broadly convex; posterior cephalic margin convex; median clypeal process triangular, apex bluntly pointed; lateral clypeal process widens mesad, median apex shaped as bluntly angular lobe that forms almost perpendicular angle with base of median process. Eye broadly convex, occupies approximately one-third of lateral cephalic margin, situated more laterad than dorsolaterad, anterad of mid-length of lateral cephalic margin. Cephalic dorsum mostly densely punctate posterad of eyes, striate-punctate to smooth with sparse punctae between eyes, longitudinally striate anterad of eye; clypeus with oblique to longitudinal striae, smoother medially; longitudinal sulcus extends posterad from between frontal carinae to one-half eye height; head posterad of eye punctate, ventral surface finely transversely striate. Scape densely punctulae, with dense decumbent pilosity and scattered subdecumbent hairs, scape extends beyond posterior cephalic margin by over one-third its length; third antennal segment over 3 x longer than apical width, second antennal segment more than half length of third segment; fourth antennal segment half length of third segment, each funicular segment slightly wider apicad than basad. Mandible elongate, external and basal margins subparallel, basal margin straight along basal one-third, convex along apical two-thirds, dorsal surface with fine weak longitudinal strigulae and sparse punctae; chewing border edentate, corner with blunt angle; PF: 4,3.

Mesosoma with metanotal groove separating convex promesonotal margin in lateral view from broadly convex dorsal propodeal margin; pronotal sculpture mostly transversely striate-punctate, posterolaterally mostly smooth with shallow punctae; propleuron mostly smooth with transverse striae anterad. Mesometapleural suture well impressed, scrobiculate; metapleural-propodeal suture distinct, metapleural margin forms narrow ledge; propodeal spiracle elongate, oriented posteriorly; bulla of metathoracic spiracle convex; mesopleuron mostly transversely finely striate posterad, with smaller areas of curved striae or rugulae, shallow broad depression present anterad, just ventrad of mesopleural spiracle; anteroventral mesopleural carina developed, forming cupped rounded lobe anterad; mesosternum transversely striate, striae parallel and more regularly impressed than striae of mesopleuron; lateral propodeal face rugulose to rugulose-punctate, or punctate, dorsum punctate to transversely striate punctate, declivitous face transversely striate, striae becoming progressively coarser posterad; declivitous face relatively flat; low triangular lobe present at spiracle height; mesonotum punctate, broader than long in dorsal view, anterior margin convex; metanotal groove convex, smooth. Propodeal spiracle elongate to slit-shaped.

Petiole sub-quadrate in lateral view, anterior margin convex, dorsal margin mostly straight to weakly convex, posterior margin inclined anterad mostly straight to weakly convex. Subpetiolar process shaped as triangular lobe in lateral view. Node subquadrate in dorsal view, slightly wider posterad than anterad, anterior margin broadly convex; posterior margin shaped as low, blunt triangle; lateral margin broadly concave. Lateral node face with longitudinal to oblique rugulae and scattered coarse punctae, ventrad tending to smooth. Anterior postpetiolar margin weakly convex in lateral view, curving onto dorsal margin; gaster mostly punctulate, constriction between abdominal segments III and IV weak; pygidium with longitudinal median crest; procoxae mostly smooth and shining in lateral view. Body with abundant decumbent pilosity and scattered standing to suberect hairs. Head, mesosoma, node and most of gaster black; antenna, mandibles, clypeus, and legs dark brown, apex of gaster brown to dark brown. Protibial apex without setae; mesotibial apex with single external seta; metatibial apex usually without external seta, occasionally present.

Type Material
Holotype worker. Costa Rica, Guanacaste, Volcán Rincón de la Vieja, Las Pailas, 27 km NE Ciudad Liberia, 700 m, 18.viii.2004, D. Kronauer, E. Rodríguez leg., deposited in. – Paratypes. Five workers from same series as holotype: 2w ; 1w, 1w , 1w.

Etymology
The species name is derived from that of the type locality in Costa Rica, Volcán Rincón de la Vieja.