Pogonomyrmex naegelii
Creators: name: Robert A. Johnson
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Formicidae
Pogonomyrmex
Pogonomyrmex naegelii

description: Pogonomyrmex naegelii
(Figures 54, 58–61)
Pogonomyrmex naegelii Forel, in Emery, 1878: X (worker, name made available); Forel 1886: XLI (worker description). Syntypes examined: 1 worker [MCZ], 2 workers [MSNG], 1 worker [USNM], BRAZIL, Rio de Janeiro (Carlos Naegeli leg.); Mayr, 1887: 612 (queen, male); Wheeler and Wheeler, 1972: 237 (larvae). See also Gallardo, 1932: 109, figs. 4, 5. MSNG worker here designated LECTOTYPE [CASENT0280989].
Pogonomyrmex (Ephebomyrmex) naegelii Forel: Wheeler, 1902: 390, first combination in subgenus Ephebomyrmex.
Ephebomyrmex naegelii (Forel): Kempf, 1972: 106, first combination in Ephebomyrmex.
Pogonomyrmex naegelii Forel: Bolton, 1995: 341, revived combination in Pogonomyrmex.
Pogonomyrmex (Ephebomyrmex) venezuelensis Weber, 1943: 69, fig. 2 (incorrectly captioned as Leptothorax anduzei) (worker). Syntypes examined: 4 workers [MCZ], VENEZUELA, Anzoátegui: from the llanos about 15 km north of Soledad, across from Ciudad Bolívar (Neal A. Weber leg., 27 January 1935). Kempf, 1960: 428 (synonomy under naegelii: here confirmed). MCZ worker here designated LECTOTYPE [CASENT0914121].
Pogonomyrmex (Ephebomyrmex) venezuelensis ssp. rupununi Weber, 1943: 71 (worker). Holotype worker [MCZ, MCZ- ENT00035809], BRITISH GUIANA, Upper Takutu-Upper Essequibo: in the southern Rupununi Savannah, #5606 (Dr. J.G. Myers leg., 11 November 1935). Kempf, 1960: 428 (synonomy under naegelii: here confirmed).
Worker. Diagnosis. Within the P. naegelii -group, the combination of: (1) approximately 8–10 coarse, longitudinal rugae between frontal lobes, (2) small lobe projecting dorsally from anterior margin of antennal fossa, (3) peduncle of petiole and anterior surface of petiolar node meet at an obtuse angle, (4) in dorsal view, posterior surface of petiolar node narrow, width similar to or slightly greater than distance between tips of superior propodeal spines, and (5) longest hairs on mesosoma rarely>0.7–0.8x MOD uniquely characterize this species (Figures 54 & 58).
Measurements —lectotype (n = 31 + 1 paralectotype). HL 1.15 (1.05–1.23); HW 1.15 (1.06–1.20); MOD 0.24 (0.22–0.28); OMD 0.28 (0.21–0.31); SL 0.84 (0.80–0.94); PNW 0.78 (0.69–0.84); HFL 1.15 (0.95–1.20); ML 1.34 (1.20–1.46); PW 0.30 (0.28–0.36); PPW 0.45 (0.40–0.49). Indices: SI 73.04 (68.97–85.45); CI 100.00 (91.53– 106.25); OI 20.87 (20.17–24.30); HFI 100.00 (84.82–103.64).
Redescription. Head subquadrate to quadrate (CI = 91.53–106.25), widest just posterior to eye; posterior margin flat to weakly concave. Longitudinal rugae on cephalic dorsum prominent, usually moderately to coarsely rugoreticulate especially medial to eyes and near posterior margin; approximately 8–10 coarse longitudinal rugae between frontal lobes; in full-face view, medial rugae not diverging toward posterior corners of head. In profile, area posterior to eyes moderately to strongly rugoreticulate. Cephalic interrugae moderately to strongly granulate, dull to weakly shining; vertex rugose to rugoreticulate. Anterior margin of clypeus flat to weakly concave, dorsal surface with numerous subparallel, longitudinal rugae; small lobe projects dorsally from anterior margin of antennal fossa. Mandible with six teeth; mandibular dorsum coarsely rugose. Up to several moderately long, curved, bristle-like, yellow-brown to brownish hairs project from anterior margin of clypeus and basolateral margin of mandibles. MOD ranging from 0.19–0.25x HL. In profile, eyes situated anterior to middle of head, OMD = 0.84–1.25x MOD. Antennal scapes moderately long (SI = 70.83–85.45), failing to reach vertex by 1.0–1.5x length of basal funicular segment; entire scape with strong longitudinal striae, dull to weakly shining. Basal flange of scape flattened, well-developed with carinate margin. Psammophore poorly-developed, consisting of short to medium-length hairs scattered across ventral side of head.
Mesosomal profile convex; all mesosomal surfaces rugoreticulate to vermiculate. Mesoepinotal sulcus sometimes weakly to moderately impressed. Dorsum of promesonotum and sides of pronotum rugoreticulate to vermiculate. Mesopleura with highly irregular rugae angling posterodorsally to rugoreticulate-vermiculate. Dorsum and sides of propodeum with irregular to very irregular, transverse rugae to occasionally rugoreticulatevermiculate. Superior propodeal spines moderately long, acuminate, connected by well-defined keel; spine length approximately 0.7–0.8x distance between their bases. Inferior propodeal spines well-developed, acuminate, length approximately 0.5–1.0x that of superior spines, base wider than length of superior spines; inferior and superior spines connected by crest that defines the propodeal declivity. Propodeal spiracles ovoid to circular facing posterad. Interrugae on mesosoma weakly to strongly granulate, dull to weakly shining to smooth and strongly shining. Legs moderately coriarious, weakly shining.
Peduncle of petiole about as long as petiolar node, anteroventral margin with weakly to strongly-developed triangular process. In profile, petiolar node asymmetrical with anterior surface shorter than posterior surface; apex weakly rounded to subangulate; anterior surface meeting peduncle of petiole at an obtuse angle. In dorsal view, petiolar node longer than wide, widest near middle, narrowing to spatulate to subangulate anterior margin; maximal width of posterior surface similar to slightly greater than distance between tips of superior propodeal spines; posterior surface and sides strongly rugoreticulate-vermiculate, interrugae weakly to moderately granulate, weakly shining. Dorsum of postpetiole convex in profile; in dorsal view, postpetiole widest at or near posterior margin, narrowing near middle to convex anterolateral margin; maximal width about equal to length; dorsum and sides moderately to coarsely rugoreticulate or with several irregular, longitudinal to oblique rugae, interrugae moderately to strongly granulate, dull to weakly shining. Ventral process of postpetiole large, bulbous, height similar to dorsal portion of postpetiole. First gastral tergum moderately to strongly coriarious, weakly shining, to smooth and strongly shining; anterior margin to anterior one-half often with weak to moderately strong longitudinal striae.
Erect yellow-brown to brownish pilosity moderately abundant on head, similar in length, mostly short, often with one or more longer hairs that approximate MOD. Moderately abundant suberect to semidecumbent pilosity on scape, abundant decumbent hairs on funicular segments. Legs with moderately abundant semidecumbent, brownish setae. Mesosoma, petiolar node, postpetiole, gastral terga with moderately dense, erect setae, mostly similar in length, longest approximately 0.7–0.8x MOD; hairs on propodeum less dense. Concolorous tan to tannish-brown with darker to blackish gaster (Figures 54 & 58).
Alate queen. Diagnosis. This caste is diagnosed by: (1) caste-specific morphology of the mesosoma related to wing-bearing and presence of ocelli on head, (2) small size (HW <1.35 mm), (3) petiolar node and postpetiole relatively narrow (petiolar node <0.45 mm, postpetiole <0.60 mm), (4) posterior surface of petiolar node rugoreticulate to vermiculate, and (5) mesoscutum and mesoscutellum rugoreticulate-vermiculate (Figure 59).
Measurements— (n = 11). HL 1.15–1.29; HW 1.15–1.26; MOD 0.24–0.32; OMD 0.23–0.30; SL 0.85–0.98; PNW 0.87–1.01; HFL 1.09–1.30; ML 1.56–1.75; PW 0.34–0.44; PPW 0.50–0.60. Indices: SI 73.91–78.86; CI 95.93–107.83; OI 20.69–25.40; HFI 87.90–108.47.
Ergatoid queen. Diagnosis. This caste is diagnosed by: (1) ergatoid, with small ocelli on head, (2) small species (HW <1.30 mm), (3) mesoscutum, mesoscutellum, and posterior surface of petiolar node rugoreticulate, (4) in profile, mesosomal outline discontinuous with a break between mesoscutellum and metanotum and between metanotum and propodeum (Figure 60).
Measurements— (n = 6). HL 1.12–1.27; HW 1.17–1.27; MOD 0.23–0.29; OMD 0.23–0.28; SL 0.83–0.94; PNW 0.89–0.99; HFL 1.09–1.22; ML 1.45–1.60; PW 0.39–0.41; PPW 0.56–0.63. Indices: SI 65.35–77.78; CI 94.49–110.71; OI 18.55–23.93; HFI 89.76–99.19.
Description. Ergatoid; small species (HW = 1.17–1.27 mm), head subquadrate to wider than long (CI = 94.49– 110.71), posterior margin flat to weakly concave. Longitudinal rugae on cephalic dorsum prominent medially, becoming rugoreticulate laterally; interrugae weakly to moderately coriarious, weakly shining. Mandible with six teeth, dorsal surface coarsely rugose. Psammophore poorly-developed, consisting of numerous short hairs scattered across ventral side of head.
All mesosomal surfaces rugoreticulate. In profile, mesoscutum and mesoscutellum flattened, mesoscutellum angled upward posterad; metanotum discontinuously connected to mesoscutellum and propodeum. Superior and inferior propodeal spines moderately well-developed, similar in length. Peduncle of petiole long, anteroventral margin with small to moderately well-developed acuminate triangular process. In profile, petiolar node asymmetrical with anterior surface notably shorter than posterior surface, apex angulate. Postpetiole slightly wider than long. Posterior surface of petiolar node coarsely rugoreticulate, dorsum of postpetiole finely rugoreticulate; interrugae weakly to moderately punctate, weakly shining. First gastral tergum weakly to strongly coriarious, dull to weakly shining with faint to moderately strong longitudinal striae near base that sometimes extend over anterior one-half of tergum. Most body surfaces with abundant suberect to erect, brownish hairs that are similar in length, longest approximately 0.5–0.7x MOD. Body concolorous tannish-brown to orangish-brown, posterior gastral terga often darker (Figure 60).
Male. Diagnosis. This caste is diagnosed by: (1) first gastral tergum lacking striae, (2) small (HW <1.10 mm; ML <2.00 mm), (3) in dorsal view, posterior surface of petiolar node rugoreticulate, (4) in profile, petiolar node rounded, (5) pronotal sides rugoreticulate, (6) in profile, inferior propodeal spines moderately well-developed, broadly rounded, and (7) notauli present (Figure 61). Note that males are unknown for P. abdominalis and P. tenuipubens.
Measurements —(n = 12). HL 0.89–1.10; HW 0.84–1.08; MOD 0.32–0.42; OMD 0.06–0.18; SL 0.14–0.23; HFL 1.03–1.40; ML 1.51–1.95; PW 0.33–0.43; PPW 0.44–0.58. Indices: SI 14.00–22.12; CI 94.38–109.18; OI 33.98–42.00; HFI 106.80–136.00.
Additional material examined. ARGENTINA: Buenos Aires: Campana, 10 m, Oct 31, 2002 (ALWC; MLPA); 10 km SE Campana, Dec 1, 2005 (CSC); Hwy 12 at 9 km N Zárate, 30’, Dec 3, 2003 (RAJC); Reserva Otamendi, 50’, Dec 3, 2003 (RAJC); Buenos Aires Zoo, 10’, Jan 10, 2011 (RAJC); Bella Vista, no date (MCZ); San Fernando, Aug 1963 (USNM); Rosas, Aug 1963 (USNM); Rt 12 at Rivadavia, 340’, Jan 20, 2011 (RAJC); Argerich, Feb 2, 1950 (FML). Chaco: Presidente Roque Sáenz Peña, Feb 7–9 & 19, 1933 (FML). Córdoba: Estancia Santo Domingo, Feb 24, 2009 (RGPC); Los Aromos, Sept 16, 2008 & Dec 14, 2008 (RGPC); Nono, 2940’, Jan 17, 2008 (RAJC); Rt 20 at 1.0 km N Nono, 2920’, Jan 23, 2006 (RAJC); 2.6 km N Nono, Dec 17, 2006 (CSC); Alta Gracia La Granja, Sierras de Córdoba, Jan 1922 (USNM); Rt 5 at 2.4 km N Alta Gracia, 1980’, Jan 24, 2006 (RAJC); Rt 5 at 3.4 km S Alta Gracia, 1830’, Jan 23, 2006’ (RAJC); 6 km SW Alta Gracia, 600 m, Jan 27, 1995 (MCZ); 22 km WSW Alta Gracia, Jan 28, 1995 (MCZ); Rt 9 at 6.5 mi E Bell Ville, 390’, Dec 21, 2005 (RAJC); Sierra Chica, 3670’, Jan 23, 2006 (RAJC); La Cruz, 1860’, Jan 16, 2008 (RAJC); Rt 9 at 3.5 km E Marcos Juárez, 330’, Jan 14, 2010 (RAJC); Unguillo, no date (MLPA); Río Calera (=El Calera), Apr 25, 1948 (FML). Corrientes: Rt 12 at Scorze Cue, 180’, Jan 18, 2011 (RAJC). Entre Ríos: Parque Nacional El Palmar, Feb 24, 2009 (RGPC); 34.7 km N Jct Rts 14 & 130, 70’, Dec 18, 2005 (RAJC); Jct Rts 14 & 22, 70’, Dec 18, 2005 (RAJC); 1.4 km W Pueblo Liebig, 70’, Feb 13, 2010 (RAJC). La Pampa: 51 km E Río Colorado, Nov 20, 2005 (CSC); General Pico, Jan 14, 1950 (FML). Mendoza: Rt 188 at 20 km W Río Salado, 1250’, Dec 4, 2003 (MCZ; RAJC); Rt 188 at 11.8 km W Canalejas, 1260’, Jan 27, 2008 (RAJC). Misiones: Esperanza, no date (MHNG); Loreto, no date (LACM; MZUSP); Loreto, 210’, Jan 13, 2011 (RAJC); Parque Nacional Iguazú at Puerto Canoas, 191 m, Mar 29, 2003 (USNM); 2 km E Bonpland, 460’, Jan 14, 2011 (RAJC); Corpus, 490’, Jan 15, 2011 (RAJC); Rt 12 at El Dorado, 730’, Jan 15, 2011 (RAJC); Rt 12 at Puerto Rico, 700’, Jan 15, 2011 (RAJC). Salta: Campo Quijano, Jan 20, 1948 (FML); Horcones, Jan 18, 1948 (FML). Santa Fe: Esperanza, Aug 3, 1949 (FML); 10 km E Santa Fe, 30 m, Oct 18, 2002 (ALWC); Rt 34 at Cañada Rosquín, 230’, Dec 21, 2005 (RAJC); Rt 65 at 4.2 mi SE Las Rosas, 310’, Dec 21, 2005 (RAJC); Rt 65 at 5.0 mi W Las Rosas, 330’, Dec 21, 2005 (RAJC); Rt 65 at Bouquet, 350’, Dec 21, 2005 (RAJC); Fives Lille, no date (MACN); Nare, Oct 1957 (FML). San Luis: 10 km E Jct Rts 148 & 188, 850’, Dec 4, 2003 (CASC; RAJC); Rt 188 at 32.0 km W Unión, 1360’, Jan 27, 2008 (RAJC); Villa Mercedes, 1700’, Dec 25, 2005 (RAJC); Rt 7 at Alto Pencoso, 2330’, Dec 27, 2005 (RAJC); Rt 7 at Balde, 1690’, Dec 27, 2005 (RAJC); Rt 20 at 1 km NE Luján, 1940’, Dec 26, 2005 (RAJC); Rt 20 at 38.8 km W Luján, 2030’, Dec 27, 2005 (RAJC); Potrero de los Funes, 3130’, Dec 25, 2005 (CASC; RAJC); La Florida, 3310’, Dec 25, 2005 (RAJC); 2.0 km S El Trapiche, 3350’, Dec 25, 2005 (RAJC); Rt 7 at 25 km SE San Luis, 2870’, Dec 12, 2003 (RAJC). Tucumán: Vipos, Rt 39, N 9, Dec 11, 1947 (FML); Villa Padre Monti, Jan 17–Feb 7, 1948 (FML). Prov. Unknown: no loc, no date (USNM). BOLIVIA: Asunción: Asunción, Oct 2, 1948 (FML). Beni: Ivón, Feb 1922 (USNM); Cavinas, no date (USNM); Reyes, Nov 1921 (USNM); Riberalta, Jan 1922 (USNM); Cachuela Esperanza, Mar 1922 (USNM); Rosario, no date (USNM); Guayaramerín, no date (FML). La Paz: Ixiamas, Dec 1921 (USNM). Tarija: Tarija, no date (FML). BRAZIL: Acre: Río Branco, Parque Zoologica, Nov 28, 1987 (MZUSP). Bahia: Anagé, Nov 2, 1990 (MZUSP); Fazenda Maria Inácia, Maracás, Nov 29, 1990 (MZUSP); Salvador, no date (MZUSP). Espírito Santo: Santa Teresa, 700 m, Feb 23, 1967 (MCZ); Pedro Canário, Oct 1972 (MZUSP). Goiás: Colinas do Sul, Serra da Mesa, Dec 2–15, 1995 (MZUSP); Anápolis, Dec 28, 1953 (MZUSP); Municipio de Anápolis at km 46 on road to Goiâna, May 10–12, 1971 (MCZ); Niquelândia, Sep 24—Oct 6, 1995 (MZUSP); Parque Nacional das Emas, Sep 6, 1996 (MZUSP). Maranhão: Balsas, Gerais de Basa, Río Mandacaru, Nov 4, 1999 (MZUSP). Mato Grosso: Municipio Diamantino, Fazanda Junquiera Vilela, Jul 17–18, 1973 (MCZ); 18 km SSW Pocone, 110 m, Nov 1, 1995 (MCZ); Várzea Grande, Jan 25, 1985 (MZUSP); Rondónopolis, Jun 11, 1972 (MZUSP); Salto de Céu, Nov 11, 1986 (MZUSP); no loc, no date (MSNG). Minas Gerais: Serra Caraca, 1380 m, Nov 1961 (MZUSP). Paraná: Iguazú Falls, Apr 12, 1989 (LACM); Rolândia, Nov 1–15, 1989 (LACM). Río de Janeiro: no loc, no date (AMNH; LACM; MCZ; USNM); Ilha Grande, Feb 7–8, 1999 (ALWC); Petrópolis, no date (AMNH); Mendes, Sep 11, 1933 (LACM); A Guanabara, Sep 8, 1941 (USNM). Río Grande do Sul: Tramandai, 1 m, Dec 20, 2008 (RAJC); São Leopoldo, no date (USNM); Campinas do Sul, Dec 1954 (USNM); no loc, 1954 (MSNG; USNM). Roraima: Ilha de Maracá, Sep 26, 1987 (MZUSP). Santa Catarina: Blumenau, Jan 19, 1972 (LACM; MCZ; MZUSP; USNM; ZSM); Nova Teutonia, Jul 1936 (LACM); no loc, no date (MCZ). São Paulo: Pindamonhangaba, Aug 25, 1961 (MZUSP); Agudos, Mar 1952 & Oct 12, 1952 (LACM; MCZ; USNM); Campos de Jordão, Oct 16, 1956 (LACM); Municipio Piracununga, Cachoeira de Emas, Feb 1967 (MCZ); Palestina, Sep 27, 1974 (MZUSP); Botucatu, Nov 15, 1953 (MZUSP); Jardim de Botânico, Agua Funda, Feb 1967 (MCZ); São Sebastião, Jan 30, 1955 & Dec 24, 1993 (LACM; MZUSP); Ilhabela, Dec 24, 1993 (MZUSP); Mirassol, Sep 27, 1970 (USNM); Barueri, Oct 25, 1958 (LACM; MZUSP); Mogy (=Mogi das Cruzes?), no date (USNM). Tocantins: Pedro Afonso, Nov 12, 1998 (MZUSP). Estado Unknown: no loc, no date (MCZ; USNM). COLOMBIA: Meta: Carimagua, May 15, 1996 (USNM). PARAGUAY: no loc, no date (MSNG). Amambay: Parque Nacional Cerro Corá, May 13, 1997 (ALWC); Pedro Juan Caballero, Aug 20, 1998 (ALWC). Boquerón: Mister Long, 460’, Sep 17–18, 2003 (RAJC; RBINS); General Eugenio Alejandrino Garay, Jun 3, 1995 (ALWC). Caaguazú: Pastoreo, Sep 29, 1974 (MZUSP); San Antonio, Feb 12, 1998 (ALWC). Canindeyú: Reserva Natural del Bosque Mbaracayú, Jejuimi, Jun 11, 1996 (ALWC; LACM; MCZ); Reserva Natural del Bosque Mbaracayú, Lagunita, Jun 11 & 16, 1996 (ALWC; LACM); 6 km N Ygatimi, Sep 30, 1996 (ALWC); 2 km W Arroyo Bandera, Feb 4, 1997 (ALWC); Camino a Mboi Jaguá, Apr 18, 1997 (ALWC). Central: Aregua, Oct 1, 1995 (ALWC; LACM); Guarambaré, Apr 25, 1997 (ALWC), no loc, Feb 20, 1940 (FML). Cordillera: Caacupé, Dec 1992 (ALWC). Guairá: Colonia Independencia, Feb 11, 1998 (ALWC). Parguari: Paraguari, no date (MCZ). President Hayes: Trans Chaco Hwy at km 140, Dec 3, 1993 (ALWC). San Pedro: Liberación, Jan 3, 1994 (ALWC); Naranjito, Dec 31—Jan 2, 1996 (ALWC). PERU: Huánuco: Huánuco, Oct 16, 1954 (CASC). Junín: El Campamiento Perené, Jul 1, 1920 (AMNH; LACM; MCZ); La Merced, Río Chanchamayo, Jun 20, 1920 (MCZ). Madre de Dios: Puerto Maldonado, 202 m, Nov 14, 2010 (RAJC); Pasco: Oxapampa, 1600 m, 1940 (MCZ). URUGUAY: Colonia: Carmelo, Río Uruguay, no date (MACN). VENEZUELA: Aragua: Corte Fuego de Mata Seca, Sendero de Mata Seca, Maracay, 516 m, Aug 28, 2003 (RAJC). Bolívar: Ciudad Bolívar, Jan 27, 1935 (MCZ). Delta Amacuro: Orinoco Delta, Jan 27, 1935 (MCZ). Guarico: Estación Biológica Llanos at 10 km S Calabozo, Jul 1–2, 1971 (MCZ). Locations not found. ARGENTINA: Tucumán?: Reserva Forestal, Rt 9 at km 1326, Mar 24, 1948 (FML); Rt 9 at km 1398, Dec 13, 1947 (FML). Questionable locales (appear to be outside geographic range): ARGENTINA: Neuquén: Hua-Hum, Jan 1, 1949 (USNM). Salta: no loc, Aug 19, 1898? (MSNG) (Figure 56 B).
Etymology. The specific epithet, naegelii (Latinization of Naegeli), is derived from Carlos Naegeli, who collected the syntype workers.
Discussion. Pogonomyrmex naegelii co-occurs with the other two P. naegelii -group species. Pogonomyrmex naegelii can be distinguished from P. tenuipubens by: (1) the approximately 8–10 coarse longitudinal rugae between the frontal lobes, (2) a small lobe that project dorsally from the anterior margin of the antennal fossa, and (3) the longest hairs on the psammophore and mesosoma are coarse, their length>0.5x MOD. In P. tenuipubens: (1) there are 16–20 fine, weak, longitudinal rugae between the frontal lobes, (2) the anterior margin of the antenna fossa lacks a lobe-like projection, and (3) the psammophore and abundant hairs on the mesosoma are very short, delicate, length <0.2x MOD, except for one to few long, coarse hairs that are sometimes present on the posterior margin of head and pronotum. Pogonomyrmex naegelii can be distinguished from P. abdominalis by: (1) usually smaller (HW = 1.05–1.23 mm), (2) a small lobe that projects dorsally from anterior margin of antennal fossa, (3) peduncle of petiole and anterior surface of petiolar node meet at an obtuse angle, and (4) width of posterior surface of petiolar node is similar to or slightly greater than distance between tips of superior propodeal spines. In P. abdominalis: (1) the body is usually larger (HW = 1.14–1.33 mm; Figure 57), (2) no small lobe projects dorsally from anterior margin of antennal fossa, (3) the peduncle of petiole and anterior surface of petiolar node meet at or near a right angle, and (4) the posterior surface of petiolar node is distinctly wider than distance between tips of superior propodeal spines.
Weber’s (1943) description of P. (E.) venezuelensis and P. (E.) venzuelensis subsp. rupununi appear to have been driven by geography rather than morphology as he notes that his records from Venezuela and British Guiana (= Guyana) bridge the considerable distribution gap between records in North America and South America. At that time, the southern most records for North American species were in Guatemala, and the northernmost record for South American species were in southern Brazil, Bolivia, and Chile. Moreover, it appears that Weber was unaware of or ignored comparing his specimens with those of P. abdominalis and P. naegelii because his paper did not mention either species. His only comment on P. venezuelensis var. rupunini was that it was larger and darker, and the gaster more heavily sculptured, being shallowly reticulate-punctate at the base compared to P. venezuelensis (Weber, 1943).
Kempf (1960) synonomized P. venezuelensis and P. venezuelensis var. rupunini under P. naegelii indicating that the description and figure of P. venezuelensis matched that of P. naegelii. He also noted that Dr. Weber failed to differentiate P. venezuelensis from other known species in the group. Kempf subsequently synonomized P. venezuelensis under P. naegelii, noting that Dr. Brown at the MCZ found no differences between the two forms when comparing a syntype of P. venezuelensis with P. naegelii from several locations. Kempf indicated that the same applied to P. venezuelensis ssp. rupunini, even though Kempf had not examined syntypes of this form.
I have examined syntypes of P. venezuelensis and P. venezuelensis subsp. rupununi, and both taxa fall within the range of morphological variation displayed within a nest series of P. naegelii. No consistent differences were observed between P. na e g el i i, P. venezuelensis, and P. venzuelensis subsp. rupununi, and the two latter forms are maintained as junior synonyms of P. naegelii. Also note that the types of P. venezuelensis ssp. rupununi are labeled as P. venezuelensis myersi (after Myers, who collected the type series); Weber apparently changed his mind about naming this form while writing the description.
Biology. Pogonomyrmex naegelii is a solitary forager that has a generalist and season-dependent diet that consists of grass seeds, and to a lesser extent nongrass species, various plant parts, and insects; ants and termites are the primary animal prey. The diet is primarily granivorous during the dry/cold season, whereas arthropods are collected to a greater extent during the warm/wet season (Belchior, Del-Claro, & Oliveira, 2012). Nests range from a cryptic entrance to a 10 cm tumulus, and they sometimes have a secondary entrance. Nests in the cerrado savanna of Brazil are relatively shallow, reaching about 70 cm below the soil surface and have 5–10 chambers (Belchior et al., 2012). Colonies are relatively small, ranging from 166–580 workers (n = 3 nests) (Belchior et al., 2012). Nests had one queen (n = 3) (Belchior et al., 2012), and the author has found multiple dealate queens in several nests. In the latter case, it is unknown if these queens were reproductive, especially given that colonies of the related North American species P. p i m a sometimes have numerous unmated dealate queens that forage (see Johnson et al., 2007).
Collection dates for sexuals range from 3–25 December. Mating flights have not been observed, but they likely occur during austral summer based on dates on which sexuals have been collected. Pogonomyrmex naegelii has both alate and ergatoid queens. From collections to date, the author has not seen any series in which both queen phenotypes were collected in the same colony, similar to observations for P. p i m a (Johnson et al., 2007). One alate queen had eight ovarioles (unpub. data).
Pogonomyrmex naegelii inhabits sites at elevations from 0–1115 m, and it is the most widespread and commonly collected Pogonomyrmex in South America. It is known from all countries except Chile, Ecuador, Suriname, and French Guiana (Figure 56 B). Pogonomyrmex naegelii occurs in numerous ecoregions, but appears to be absent from deserts, rainforests, and high-elevation areas.
description: Published as part of Robert A. Johnson, 2015, A taxonomic revision of South American species of the seed-harvester ant genus Pogonomyrmex (Hymenoptera: Formicidae). Part I, pp. 1-142 in Zootaxa 4029 (1) on pages 111-119, DOI: 10.11646/zootaxa.4029.1.1