Patagonomyrmex angustus, Johnson, Robert A. & Moreau, Corrie S., 2016

Johnson, Robert A. & Moreau, Corrie S., 2016, A new ant genus from southern Argentina and southern Chile, Patagonomyrmex (Hymenoptera: Formicidae), Zootaxa 4139 (1), pp. 1-31 : 12-17

Patagonomyrmex angustus NEW COMBINATION

( Figures 2–4 )

Pogonomyrmex angustus Mayr, 1870: 970 (worker, in key). Syntypes examined: 2 workers [MHNG], 1 worker [NMW], CHILE, Valdivia (Edm. Reitter); Mayr, 1887: 612 (queen, male). See also Gallardo, 1932: 103; Kusnezov, 1949: 294. NMW worker here designated LECTOTYPE [CASENT0173374].

Pogonomyrmex (Ephebomyrmex) angustus Mayr ; Emery, 1921: 48, first combination in Pogonomyrmex (Ephebomyrmex) .

Ephebomyrmex angustus (Mayr) ; Kusnezov, 1960: 353, first combination in Ephebomyrmex .

Pogonomyrmex angustus Mayr ; Snelling & Hunt, 1975: 72, fig. 23, revived combination in Pogonomyrmex .

Worker. Diagnosis. This species is 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 ( Figure 2 ).

Measurements. 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).

Redescription. 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 ( Figure 2 ).

Queen. Diagnosis. This caste is diagnosed by: (1) caste-specific morphology of the mesosoma related to wingbearing and presence of ocelli on head, (2) mesoscutum and mesoscutellum with weak to moderately strong longitudinal rugae, interrugae weakly to strongly granulate-punctate, (3) inferior propodeal spines elongate, length similar to that of superior propodeal spines, and (4) body concolorous brownish-black to black ( Figure 3 ).

Measurements —(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. Diagnosis. This caste is diagnosed by: (1) mesopleura, metapleura, pronotal sides, and dorsum of propodeum strongly granulate, dull, with a beaded appearance, (2) at least several hairs on ventral surface of head approach or exceed MOD, and (3) scape length sometimes> 0.6 mm, SI> 70.0 ( Figure 4 ).

Measurements —(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.

Additional material examined. ARGENTINA: Chubut: El Bolsón, Feb 12, 1949 ( FML; LACM; MHNG); Lago Menéndez, no date ( USNM). Neuquén: Lago Brazo Huemul Nahual Huapi, 2840’, Jan 26, 2011 ( MCZ; RAJC); Río Caleufu, 20 mi W Collon-Curá, Mar 9–14, 1980 ( CASC); Hua Hum, Jan 26, 1949 ( CASC; LACM; MHNG); Quilaquina, no date ( MACN); San Martín de los Andes, 800 m, Jan 8, 1995 & no date ( MCZ; MLPA; PSWC; UCDC); Pucará, no date ( MHNG; MZUSP); Parque Nacional Lanín, Lago Paimun-La Cascada, Jan 26, 1999 ( FML). Río Negro: Cerro Lopez, 1003 m, Jan 2005 ( MCZ; RAJC); 11.4 km E Llao Llao, 760 m, Nov 16, 1966 ( CASC); 5.6 km N Río Foyel, 920 m, Nov 18, 1966 ( CASC); Victoria Nahuel Huapi, May 27, 1971 ( MZUSP). CHILE: La Araucanía: Cerro de Naguelbuta, Angol, 620 m & 650 m, Oct 12, 1931 ( MCZ); 10 km E Pucon, Jan 12, 1951 ( CASC; LACM); Temuco, no date ( MCZ); 20 km E Temuco, Jan 8, 1951 ( CASC; USNM); 12.3 km N Loncoche, 280 m, Nov 10–16, 1966 ( CASC; LACM). Biobío: Chillan Cordillera, Mar 12, 2005 ( CASC); Cordillera Nahuelbuta, 20 km W Caramávida, 750 m, Jan 31, 1967 ( CASC); 50 km E San Carlos, Dec 26, 1950 ( MCZ). Los Lagos: Pucatrihue, 0 m, Feb 4, 1967 ( CASC). Los Ríos: Puerto de Corral, Mar 1904 ( MHNG); Corral, no date ( MHNG); Valdivia, Feb 1879 & no date ( MCZ; MLPA). Maule: Cuyurranquill, 400 m, Jan 23–31, 1981 ( USNM); Cajón de Río Claro, SE Los Queñes, 1000 m, Oct 9, 1966 ( CASC). Metropolitan: Cuesta de la Dormida, 1000 m, Nov 1, 1966 ( CASC; LACM); Cerro el Roble, ca 2000 m, Oct 22, 1972 ( LACM); Reserva Nacional Río Clarillo, comuna Pirque (not examined, literature record from Solervicens, Estrada, & Márquez, 1991). O’Higgins: 3 km N Callejones, Jan 22, 1967 ( CASC). Valparaíso: 90 km S Illapel, Nov 28, 1950 ( CASC); Río Marga Marga, Los Perales, 330 m, Oct 13, 1966 ( CASC); Parque Nacional La Campana (not examined, literature record from Ipinza-Regla, 1985 & Sáiz & Carvajal, 1990). Region Unknown: no loc, no date ( USNM) ( Figure 5 A).

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

Discussion. Patagonomyrmex angustus co-occurs with both Pa. laevigatus and Pa. odoratus . It is distinguished from the latter two species based on the following characters: (1) dorsum of promesonotum and posterior surface of petiolar node strongly granulate-punctate, weakly shining (dorsum of promesonotum and posterior surface of petiolar node smooth and shining in Pa. laevigatus and Pa. odoratus ), and (2) inferior propodeal spines elongate, length similar to that of superior propodeal spines (the inferior propodeal spines are triangular and notably shorter than superior propodeal spines in Pa. laevigatus and Pa. odoratus ). We did not find any morphological measurements that could be used to separate Pa. angustus from its two congeners.

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.

Figures

FIGURE 2. Photograph of Patagonomyrmex angustus (Mayr) worker: (A) frontal view of head, (B) lateral view of body, (C) dorsal view of body (CASENT 0106125). Photos taken by Michael Branstetter and www. antweb. com.

FIGURE 3. Photograph of Patagonomyrmex angustus (Mayr) alate queen: (A) frontal view of head, (B) lateral view of body, (C) dorsal view of body (CASENT 0914808). Photos taken by Michele Esposito and www. antweb. com.

FIGURE 4. Photograph of Patagonomyrmex angustus (Mayr) male: (A) frontal view of head, (B) lateral view of body, (C) dorsal view of body (LACMENT 273603). Photos taken by Michele Esposito and www. antweb. com.

FIGURE 5. Geographic distribution of: (A) Patagonomyrmex angustus (Mayr), (B) Patagonomyrmex laevigatus (Santschi), and (C) Patagonomyrmex odoratus (Kusnezov); the larger filled black circle in each panel (when present) denotes the type locality.