Probolomyrmex kelleri

An entire colony of this species was found in an area of dry forest with much thorny scrub vegetation in Lara, Venezuela, under a stone, containing 16 workers, two queens, two males, three pupae, and 15 late instar larvae. When uncovered, most of the ants were found clinging to the underside of the stone. They did not run away, presenting a sluggish and frozen behavior (John Lattke, unpublished data). One of these workers and another specimen from Aragua (Venezuela) have eyes formed by a unique omatite. Locality data suggests that it inhabits mesic as well as dry forests.

Identification
Oliveira & Feitosa (2019) - Postero-ventral petiolar lobe short and rounded. Subpetiolar process well developed, ventrally concave to subrectangular, with the postero-ventral angle acute and directed towards the gaster. Prora and protuberance on the posterior region of the first gastral tergite present.

Probolomyrmex kelleri resembles Probolomyrmex boliviensis, but is smaller, with shorter antennal scapes and subpetiolar process well developed.

Distribution based on Regional Taxon Lists
Neotropical Region: Guyana, Peru, Venezuela.

Nomenclature

 *  kelleri. Probolomyrmex kelleri Oliveira & Feitosa, 2019: 81, figs. 20-23 (w.q.m.) VENEZUELA.

Worker
(n=8) HL 0.57–0.64; HW 0.35–0.40; SL 0.35–0.41; WL 0.70–0.78; PL 0.25–.28; PW 0.28–0.34; PH 0.25–0.30; TL 1.96–2.62; CI 56.5–64.5; SI 59.5–64.5; PI 93.5–106.5.

Frontoclypeal shelflike projection and mandibles with hair-bearing tubercles or cylindrical micro-pegs; external surface of mandibular basal margin transversely micro-striate. Tip of apical segment of antennae bearing minute pits. Mesopleuron foveated and micropunctate; metapleuron alveolate and foveated; lateral faces of propodeum foveated and micropunctate; alveoli denser just above metapleural gland orifice; opening of metapleural gland large, with a smooth anterior region, surrounded by rows of hairs. Petiolar node and postero-ventral lobe of petiole with incomplete foveae and micropunctures; subpetiolar process alveolate and latero-ventral region of petiole alveolate. Posterior region of second gastral tergite with transversal rows of deep rounded pits.

Space between mesosomal foveae covered by dense pubescence. Pygidium with dense pubescence and some long and thick hairs.

Head 1.6 times longer than wide. Hypostomal margin curved. Antennal scapes extend to head midlength, distance from scape apex to of head more than two times pedicel length (SI 59.5–64.5). Propodeum emarginated posteriorly on each side by a narrow carina, with teeth at their apexes. Petiole as long as high (PI 93.5 106.5), without teeth; posterior face long, slightly concave and smooth; postero-ventral lobe short and rounded; subpetiolar process with a projection ventrally concave or subrectangular with the posteroventral angle acute, directed downwards or towards the gaster. First gastral segment with prora and a dorsal protuberance on posterior region of tergite, characterized by a gentle elevation of the integument.

Queen
(n=4) HL 0.57–063; HW 0.37–0.40; SL 0.35–0.43; WL 0.78–0.85; PL 0.26–0.30; PH 0.26–0.28; TL 2.59–2.85; CI 62.5–67.5; SI 61–67; PI 93–100.

With the morphological modifications described for Probolomyrmex queens and the diagnostic characters of the workers

Male
(n=1) HL 0.44; HW 0.44; SL 0.26; PL 0.19; PH 0.17; TL 1.98; CI 98; SI 58.3; PI 85.7.

Scapes long, distance from scape apex to of anterior ocellus lesser then pedicel length. Propodeum without lateral carina, teeth absent, lateral surface smooth and shining. Petiole slightly longer than high, apical teeth absent. Anterior face longer then posterior face, apex rounded. Subpetiolar process weakly developed. First gastral segment with weakly developed prora and dorsal protuberance on posterior region of tergite.

Type Material

 * Holotype: VENEZUELA: Lara: Finca Sta. Maria 3.8km, ESE Barbacoas, 9°49’N 70°2’W, 26.xii.2005, J. Lattke col 2978 (worker) [DZUP, unique specimen identifier DZUP 549763].
 * Paratype: same data as holotype, except: (1 worker) [DZUP, unique specimen identifier DZUP 549764]; (1 queen) [DZUP, unique specimen identifier DZUP 549765]; (1 male) [DZUP, unique specimen identifier DZUP 549766]; 2978 (1 worker) [MZSP]; 2978 (1 worker) [MIZA].

Etymology
This species is described in honor of Dr. Roberto Keller, prominent ant morphologist whose work has been inspiring old and new generations of myrmecologists.

References based on Global Ant Biodiversity Informatics

 * Oliveira A. M., and R. M. Feitosa. 2019. Taxonomic revision of the genus Probolomyrmex Mayr, 1901 (Hymenoptera: Formicidae: Proceratiinae) for the Neotropical Region. Zootaxa 4614: 61–94.