Pachycondyla lenkoi

The biology of this species is unknown.

Identification
From Mackay and Mackay (2010): Kempf (1962) compares P. lenkoi with Pachycondyla harpax and Pachycondyla lenis,  but states that it is readily recognized by its much smoother and shinier integument and by the completely different petiolar node. In Kempf (1961) it would key with Neoponera metanotalis, but differs in its smaller size with smoother and shinier integument and by the less compressed petiolar node, the shorter funicular segments (3 - 4), the weaker lateral margination of the pronotum and especially in the lack of the stridulatory file on the second pretergite of the gaster. The elongate mandibles with the reduced number of teeth (seven) distinguishes P. lenkoi from most of the other known species in the genus, but is similar to that of members of the stigma species complex. Pachycondyla lenkoi can be separated from most of the members of the stigma species complex by the slit-shaped propodeal spiracle. It can also be easily distinguished from the other members of the stigma species complex by the subpostpetiolar process, which is completely different from the other members in which the process consists of a collar-like flange. In P. lenkoi the process is formed into a relatively sharp tooth, which is followed posteriorly by a longitudinal carina which is positioned on the ventral anterior surface of the postpetiole. The process is similar to that found in Paltothyreus tarsatus, but P. lenkoi and P. tarsata are very different and do not appear to be closely related. It is likely that P. lenkoi is not a member of the stigma species complex, but if removed, would have to be placed in its own species complex. It will be left here until it can become better known.

Pachycondyla lenkoi somewhat bridges between the stigma complex and the ferruginea complex, having the mandible and strongly developed transverse clypeal carina of the first complex and the most of the remainder, especially the subpetiolar process of the ferruginea species complex. Surprisingly the propodeal spiracle of P. lenkoi is slit-shaped, unlike either complex. Pachycondyla lenkoi is arbitrarily placed in the stigma complex based on the form of the mandible and clypeus. It is most similar to Pseudoponera succedanea in the stigma complex, but can be easily separated by the lack of a depressed metanotal suture on the dorsum of the mesosoma and the slit-shaped propodeal spiracle.

The polished mandibular surface could cause confusion with the smaller Rasopone minuta (total length of the worker 4.5 mm, of the female ~ 4 mm), but is larger and lacks the round propodeal spiracle of P. minuta. Pachycondyla lenkoi is similar to the Central and South American Rasopone ferruginea in size, color and shape of the petiole and subpetiolar process. Pachycondyla lenkoi can easily be separated by the 7-toothed mandible (about 10 in R. ferruginea) and the slit-shaped propodeal spiracle (circular in R. ferruginea).

Distribution
BRASIL, BOLIVIA (Mackay and Mackay 2010)

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil.

Castes
Known only from the worker caste.

Nomenclature

 *  lenkoi. Pachycondyla lenkoi Kempf, 1962b: 4, figs. 1-4 (w.) BRAZIL. See also: Mackay & Mackay, 2010: 430.

Worker
From Mackay and Mackay (2010): (based partially on Kempf, 1962.) The worker is a moderate sized (total length 6.5 - 8 mm) ferrugineous red to black ant with the mandibles, clypeus, frontal lobes, legs, sides of the petiole node, sides and apex of the gaster ferrugineous or fuscous ferrugineous. The head is subquadrate with the sides slightly convex and with the posterior border slightly concave. The mandibles have seven unequal sized teeth. The anterior half of the clypeus is separated from the posterior half by a well-developed transverse crest, forming a blunt tooth in the middle and with an elongate tumulus behind the tooth, which turns into a keel that extends back between the frontal lobes. The head length is 1.56 mm; the head width is 1.48 mm. The sides of the head are nearly straight and only slightly narrowed anteriorly, the posterior border is slightly concave. The eyes are small (maximum diameter 0.19 mm) located about 1 diameter from the anterior margin of the head (side view), but relatively large for a member of the stigma species complex, and separated from the anterior edge of head by approximately two diameters (side view). The scapes (1.05 mm) extend to the posterior lateral corners of the head. The pronotal shoulder has a poorly defined carina and the metanotal suture is barely marked and not depressed on the dorsum of the mesosoma. The propodeal spiracle is slit-shaped. The petiole is thickened when viewed in profile; with a vertical slightly concave anterior face and broadly rounded posterior face, which meet near the anterior edge of the petiole. The node of the petiole, viewed from above, is half-moon shaped; the sides of the posterior face are slightly marginate on the lower half. The subpetiolar process is large and angulate posteriorly. The pretergite of the second gastral segment lacks a stridulatory file. The posterior medial surface of the pygidium has an ill-defined highly polished and hairless area, surrounded by a fringe of long hairs.

The body and appendages have erect or suberect brownish golden hairs (up to 0.45 mm). Shorter (0.2 - 0.3 mm) hairs are present on the dorsum and ventral surfaces of the head, sides and posterior border of the head, scapes, dorsum of the mesosoma, dorsum of the petiole and gaster. The appressed golden pubescence is rather long dense and conspicuous on the dorsum of the head, thorax, petiole and gaster, but never masking the integument and the tarsi, especially of the mid and hind legs, have short oblique stout setae.

The mandible is smooth and shining with sparse piligerous punctures. The dorsum of the head is densely and coarsely punctate with the intervals smooth and shining. Coarse punctures become sparse on the sides of the head and are extremely rare on the nearly smooth and highly polished ventral surface of the head. The clypeus and frontal lobes are rather smooth and shining. The mesosoma is feebly sculptured throughout and quite shining. The neck of the pronotum has a few irregular, but rather longitudinal rugosities. The pronotum is sparsely and rather coarsely punctate above and more shallowly on the sides. The mesonotum is sparsely and feebly punctured, the dorsal and posterior faces of the propodeum are nearly smooth and shining, the sides of the mesosoma have horizontal rugae above and are smooth and shining below. The petiole is smooth and glossy with scattered punctures. The gaster is moderately smooth and glossy with scattered punctures.

Type Material
Brasil, Mato Grosso: Rio Sacre (Mackay and Mackay 2010)

Etymology
This species is named to honor the well known Brasilian myrmecologist, Karol Lenko, who collected the holotype. (Mackay and Mackay 2010)