Leptogenys wheeleri

A nest series from Reserva Sian Ka’an are associated with the bromeliad Aechmea bracteata, with nests found in dry ramets (Dejean 1997). The series from Veracruz is from evergreen forest, and one worker is point-mounted along with an isopod. The specimens at hand suggest a clinal difference in size with the northernmost species as the largest. Dejean & Evraerts (1997) studied the predatory behavior of several Leptogenys species, suspecting L. wheeleri may attract its isopod prey into the nest by chemical means. (Lattke 2011)

Identification
Key to Leptogenys of the New World

Lattke (2011) - A member of the wheeleri species group. Eyes weakly convex; mandible parallel-sided, basal margin with weak convexity close to base; median clypeal lobe projects abruptly from anterior margin of lateral clypeal lobes, meeting at almost perpendicular angle.

Distribution
This taxon was described from Mexico. It is known from central Mexico – Panama.

Nomenclature

 *  wheeleri. Leptogenys wheeleri Forel, 1901c: 123 (w.) MEXICO. Lattke, 2011: 226 (m.).

Worker
Lattke (2011) - Metrics (n = 5) : HL 1.28 – 1.62; HW 1.15 – 1.58; ML 0.91 – 1.25; EL 0.34 – 0.4; SL 1.25 – 1.75; PW 0.84 – 1.08; WL 2.06 – 2.63; PH 0.81 – 1.01; PL 0.61 – 0.84; DPW 0.64–0.78 mm. CI 0.87–1; MI 0.75–1; OI 0.25– 1; SI 1.03 – 1.18; LPI 1.2 – 1.33; DPI 0.92 – 1.06.

Head subquadrate in full-face view, lateral cephalic margin broadly convex, posterior margin broadly convex; head wider anterad than posterad; eye large, broadly convex, occupies one-third of lateral cephalic margin. Median clypeal lobe broadly triangular, apex bordered by translucent lamella; lateral lobe poorly developed. Scape surpasses posterior cephalic border by close to one-third its length; length of third antennal segment twice its width; length of fourth antennomere only slightly more than its width; length of third segment almost twice that of fourth. Mandible arched and slender, widely separated from clypeus, external and basal margins subparallel in cephalic full-face view, dorsum shining, mostly with fine striolae, becoming smooth at apex; PF: 4,3.

Mesosoma with dorsal margin roughly convex in lateral view; pronotal margin mostly broadly convex except for brief concave anterior section; promesonotal suture and metanotal groove weakly impressed; mesonotum weakly convex in lateral view; propodeal dorsal margin mostly convex, declivitous margin straight to slightly concave. Declivitous and dorsal propodeal margins meet through blunt obtuse angle in lateral view. Mesometapleural suture well impressed; mesopleuron with carina along anteroventral margin, carina widest anterad; metapleural-propodeal suture barely impressed; propodeal spiracle elongate, facing posterad; brief sulcus extends from spiracle to bulla. Mesonotal width in dorsal view almost twice its length; propodeal declivitous face mostly flat.

Petiole subquadrate in lateral view, anterior margin vertical up to two-thirds node height, then sharply convex, dorsal margin broadly convex with brief posterior depression; posterior margin weakly sinuate, mostly straight to slightly concave dorsad, with weak convexity ventrad; posterior face slightly concave. Subpetiolar process shaped as broad lobe. Node subquadrate in dorsal view, slightly wider posterad than anterad. Gastral constriction well developed. Procoxa mostly rugulose in lateral view. Body densely punctulate, giving cuticle a shagreened appearance. Punctulae on head, mesosoma, and petiole separated by ridge, forming a reticule; punctulae on gaster more spaced, separated by distances from 0.5 to 1 diameter. Sculpture of head coarser anterad of eyes than on rest of head. Body with short appressed pubescence, standing hairs absent except on gastral apex and sparse hairs on ventral area. Body grey brown to light brown, mandibles ferruginous brown to brown, antennae grey-brown; legs yellow-brown to ferruginous brown.

Queen
Lattke (2011) - Metrics: HL 1.27; HW 1.11; ML 0.83; EL 0.30; SL 1.27; PW 0.83; WL 2.00; PH 0.89; PL 0.56; DPW 0.73 mm CI 0.88; MI 0.75; OI 0.27; SI 1.14; LPI 1.59; DPI 1.32. As worker, but with broader petiole in dorsal view, and dorsal propodeal margin more convex in lateral view.

Male
Lattke (2011) - Metrics: HL 0.83; HW 0.96; ML 0.23; EL 0.56; SL 0.28; PW 1.04; WL 2.07; PH 0.43; PL 0.28; DPW 0.35 mm CI 1.15; MI 0.24; OI 0.58; SI 0.29; LPI 1.55; DPI 1.27. Distance separating median ocellus from lateral ocelli less than width of median ocellus; cephalic dorsum mostly smooth and shining with punctulae, punctulae denser on clypeus, clypeus divided by transverse suture into anterior and posterior sections. Mesonotum receded from pronotum in lateral view by distance equal to maximum width of profemur, forming step. Mesosoma mostly smooth and shining with sparse to dense punctae; punctae denser on posterior scutum; metapleuron rugulose; gaster with blue iridescence. Body with abundant decumbent hairs, longer than on worker, longest hairs on ventral portion of mesosoma and gaster. Body brown; mandibles, pronotum, and legs, beige; propodeum slightly lighter brown than rest of mesosoma.

Type Material
Holotype worker: Mexico, Morelos, Cuernavaca (W.M. Wheeler) [examined].

The MHNG type specimen appears to be the only specimen, at least in the MHNG and has a label with Forel’s handwriting explicitly stating “typus”.

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 & Phylogeny, 69, 127-264. PDF]]