Leptogenys ingens

The species has been taken in forests that range from cloud forest to dry forest, and an altitudinal range from sea level to 1100 m. It is a specialised predator of terrestrial isopods, its nests frequently easy to discern due to the pile of bleached isopod remains that fan out from the entrance. Nests are in the soil, with chambers usually in contact with roots, or beneath decomposing trunks or large branches, sometimes under stones. Workers have been observed foraging during the day. Despite the excavation of several nests, no recognizable queens have been found, leading to believe they are morphologically indistinct from the workers. (Lattke 2011)

Identification
Key to Leptogenys of the New World

Lattke (2011) - A member of the ingens species group. Large species, median clypeal lobe prominent, apex truncate with smaller median lobe; lateral median lobe triangular, prominent; petiolar node subquadrate in lateral view with prominent apical blunt point, subpetiolar process claw shaped in lateral view, almost as tall as the vertical width of the petiolar peduncle.

This spectacular and easily determined species is the largest of the New World Leptogenys. Even though some specimens of Leptogenys famelica are comparable in total length, L. ingens is more robust than the slender L. famelica.

Distribution
Lattke (2011) - Almost all specimens of this species are known from the northern coastal mountains of Venezuela, except for the type specimen, which is from an unspecified location in Colombia, and a population on Margarita Island, close to the Venezuelan mainland. Since the Venezuelan Cordillera de la Costa is part of the Caribbean Mountain System (Meier 1998), the possibility exists this species can be found in the Sierra Nevada de Santa Marta to the West, and the Arima Range to the East. They are particularly abundant in the Serranía de San Luis, Falcón State, Venezuela.

This taxon was described from Colombia.

Castes
Queens and males are unknown.

Nomenclature

 *  ingens. Leptogenys ingens Mayr, 1866a: 503 (w.) COLOMBIA. See also: Lattke, 2011: 175.

Worker
Lattke (2011) - HL 2.12-2.73; HW 2.02-2.53; ML 1.82-2.12; EL 0.61-0.61; SL 2.83-3.23; PW 1.52-1.92; WL 4.24-5.05; PH 1.82-2.12; PL 1.41-1.62; DPW 0.91-1.21 mm. CI 0.87-1.19; MI 0.76-1.00; OI 0.24-0.30; SI 1.24-1.55; LPI 1.27-1.50; DPI 0.60-0.80.

Head wider anterad than posterad in full-face view, lateral and posterior margin forming continuous convexity, slightly bulging at mandibular insertion; anterior clypeal margin with lateral triangular lobe, median lobe projecting abruptly, apex truncate except for smaller median rounded lobe. Eye convex, dorsolaterally placed on head, ocular diameter at least one-fourth length of cephalic lateral margin. Area between compound eye and frontal lobe with longitudinal to oblique rugae; area posterad of eye transversely rugulose-punctulate. Frontal lobe forms longitudinal crest extending posterad to mid-eye distance; dorsal lobe of torulus laterally expanded, partially covering antennal condyle. Scape surpasses posterior cephalic margin by more than one-fourth its length, with fine piligerous punctulae, pubescence and inclined pilosity; fourth antennal segment as long as or longer than following two segments combined. Mandible slightly arched in cephalic full-face view, leaving wide space between basal margin and clypeus, dorsally shining, punctate with fine longitudinal etchings; slightly expanding in width from mid-length apicad; basal and masticatory margins separated by single fine denticle; masticatory margin with median notch and apical triangular angle. Ventral cephalic face mostly shining with blue opalescence, hypostomal tooth distinct, not visible in dorsal cephalic view. PF 4,3.

Mesosoma with pronotal margin forming single convexity separated by metanotal groove from broad concavity of dorsal propodeal margin in lateral view; pronotum laterally mostly smooth with blue opalescence, posterolaterally and anteriorly rugulose; dorsum densely punctate anterad and medially, sparse posterad; mesonotum punctate, punctae sparse medially; metanotal groove deeply impressed; propodeal dorsum transversely rugulose punctate; meso- and metapleuron transversely rugulose; mesometanotal suture well impressed.

Propodeal spiracle slit-shaped, vertical, opening posterolaterally, placed at least 2 lengths from declivity in lateral view. Petiolar node with anterior margin continuously convex in lateral view, with a blunt posterior tooth overhanging the concave posterior margin; mostly smooth with transverse rugulae posterolaterally and most of posterior face. Abdominal segments III – IV smooth and shining with sparse punctulae. Head, mesosoma, abdominal segments II – IV black with blue opalescence; remaining abdominal segments, and legs ferruginous brown; scape and mandible brown; funicular segments I – II ferruginous brown, other segments ferruginous. Body with abundant erect to sub-erect hairs; coxae mostly smooth with sparse punctulae.

Type Material
Holotype worker: Neu Granada (= Colombia) [examined]. Even though Mayr did not specify how many specimens he examined, the studied type seems to be the only specimen thus becoming holotype by default.

Additional References

 * [[Media:Lattke 2011.pdf|Lattke, J. E. 2011. Revision of the New World species of the genus Leptogenys Roger (Insecta: Hymenoptera: Formicidae: Ponerinae). Arthropod Systematics and Phylogeny 69:127-264. [2011-12-13] PDF]]