Patagonomyrmex angustus

Identification
Worker Uniquely characterized by the following combination of features: (1) strongly granulate-punctate interrugae on cephalic dorsum and dorsum of mesosoma, (2) posterior surface of petiolar node and dorsum of postpetiole moderately to strongly granulate-punctate, weakly shining to dull, (3) rugae on cephalic dorsum continue to posterior margin, (4) inferior propodeal spines long, length similar to that of superior spines, and (5) body concolorous dark brownish-black to black, usually with dark brown legs

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Chile.

Nomenclature

 *  angustus. Pogonomyrmex angustus Mayr, 1870b: 970 (w.) CHILE. Mayr, 1887: 612 (q.m.).
 * Combination in P. (Ephebomyrmex): Emery, 1921f: 48.
 * Combination in Ephebomyrmex: Kusnezov, 1960b: 353.
 * Combination in Pogonomyrmex: Snelling & Hunt, 1976: 72.
 * Combination in Patagonomyrmex: Johnson & Moreau, 2016: 12.
 * See also: Gallardo, 1932b: 103.

Worker
Johnson and Moreau (2016) - Lectotype (n = 15). HL 1.25 (0.97–1.32); HW 1.12 (0.81–1.16); MOD 0.27 (0.21–0.29); OMD 0.27 (0.18–0.26); SL 0.93 (0.78–1.00); PNW 0.79 (0.59–0.82); HFL 1.21 (0.89–1.25); ML 1.59 (1.21–1.58); PW 0.31 (0.23–0.34); PPW 0.44 (0.36–0.51). Indices: SI 83.01 (83.04–104.94); CI 89.60 (80.58–91.74); OI 24.11 (21.55–29.63); HFI 108.04 (103.60–118.52).

Longitudinal rugae on cephalic dorsum coarse, weakly wavy, running from frontal lobes to posterior margin; posterior margin flat in full-face view. Rugae on lateral surfaces more irregular, usually weaker than those on cephalic dorsum. Interrugae on cephalic dorsum strongly granulate-punctate, dull; vertex rugose. Dorsum of clypeus with several moderately coarse, subparallel, longitudinal rugae. Mandible with six teeth; mandibular dorsum strongly rugose. MOD ranging from 0.19–0.24x HL. In profile, eyes situated anterior to middle of head, OMD = 0.73–1.05x MOD. In full-face view, eyes protruding slightly beyond lateral margins of head. Antennal scapes long (SI = 83.01–104.94), reaching vertex; scapes moderately to strongly granulate-punctate, often with faint striae, dull; basal flange moderately well-developed with carinate margin.

Mesosomal profile weakly convex; dorsum of promesonotum with moderately coarse, irregular rugae; longitudinal rugae on mesospleura and metapleura wavy to irregular. Interrugae on promesonotum strongly granulate-punctate, dull; promesonotal suture usually faintly to weakly impressed. Superior propodeal spines long, acuminate, length rarely >0.7–0.8x the distance between their bases; inferior propodeal spines well-developed, longer than wide, acuminate, length similar to that of superior spines. Propodeal spiracles weakly ovate to circular facing posterad. Legs smooth and shining to weakly granulate, weakly shining.

Peduncle of petiole about 0.7x as long as petiolar node, anteroventral margin of peduncle of petiole with a small, acuminate spine. In profile, posterior surface of petiolar node weakly convex; petiolar node asymmetrical with anterior surface shorter than posterior surface, apex bluntly subangulate to rounded. In dorsal view, petiolar node longer than wide, sides subparallel, narrowing to a rounded to subangulate anterior margin; all surfaces of petiolar node strongly granulate-punctate, dull, occasionally with few weak rugae. Dorsum of postpetiole convex in profile; in dorsal view, widest near posterior margin, narrowing to anterior margin, maximum width and length similar; dorsum and sides moderately granulate-punctate, weakly shining. First gastral tergum smooth and shining.

Erect to suberect, medium-length, white to cream colored hairs moderately abundant on head, few hairs >0.5x MOD. Moderately abundant subdecumbent to decumbent hairs on antennal scapes; abundant decumbent to appressed hairs on funicular segments. Legs with moderately abundant subdecumbent to decumbent setae. Mesosoma with moderate number of medium-length erect to suberect setae, but few present on propodeum, longest hairs usually about 0.7–0.8x MOD; petiolar node, postpetiole, gastral terga with sparse medium-length setae, longest notably shorter than MOD. Body mostly concolorous dark brownish-black to black; antennae, legs dark brown.

Queen
Johnson and Moreau (2016) - (n = 11). HL 1.10–1.39; HW 0.99–1.22; MOD 0.26–0.31; OMD 0.18–0.30; SL 0.82–1.03; PNW 0.71–0.97; HFL 1.06–1.28; ML 1.57–1.87; PW 0.33–0.38; PPW 0.46–0.59. Indices: SI 79.66–87.27; CI 82.58–94.40; OI 22.13–28.44; HFI 99.15–110.09.

Male
Johnson and Moreau (2016) - (n = 6). HL 1.03–1.19; HW 0.88–1.01; MOD 0.35–0.42; OMD 0.11–0.22; SL 0.28–0.78; HFL 1.11–1.23; ML 1.54–1.71; PW 0.26–0.30; PPW 0.42–0.49. Indices: SI 31.82–80.41; CI 84.62–92.59; OI 36.08–43.18; HFI 117.00–126.14.

Type Material
Johnson and Moreau (2016) - Syntypes examined: 2 workers [], 1 worker [], Chile, Valdivia (Edm. Reitter); Mayr, 1887: 612 (queen, male). See also Gallardo, 1932: 103; Kusnezov, 1949: 294. NMW worker here designated Lectotype [CASENT0173374].

Mayr (1870) described the worker of Pa. angustus in a key with no additional information, and he later described the queen and male (Mayr, 1887) listing the type locality as “Valdivia in Chile”. As noted by Kusnezov (1949), this vague location does not indicate if the type locality was in the city or province of Valdivia.

Etymology
Johnson and Moreau (2016) - The name of this species, angustus (from Latin, angustus = narrow, small), is derived from the narrow body, as discussed in the description by Mayr.