Pogonomyrmex catanlilensis, Gallardo, 1931

Johnson, Robert A., 2021, A taxonomic revision of South American species of the seed-harvester ant genus Pogonomyrmex (Hymenoptera: Formicidae). Part II, Zootaxa 5033 (1), pp. 1-230 : 67-69

Pogonomyrmex catanlilensis

( Figures 29–31 )

Distribution—32A

Pogonomyrmex catanlilensis Gallardo, 1931 ; 187, fig. 2 (worker). Syntypes examined: 2 workers [MACN]. ARGENTINA, Neuquén: on the road from Zapala to Junín de los Andes near the Catán Lil River, #12261 (A. Gallardo leg., 10 April 1919). See also Gallardo, 1932: 163, fig. 43; Kusnezov, 1951: 273. MACN worker here designated LECTOTYPE [CASENT0235275].

Worker diagnosis. Workers of this species are uniquely characterized by the following combination of features: (1) striae cover anterior one-half or more of first gastral tergum, (2) head and mesosoma blackish to black, gaster dark ferruginous orange to orangish-black, (3) relatively large (HW = 1.67–2.04 mm; PNW = 1.15–1.42 mm; ML = 2.01–2.76 mm), (4) mandibles with six to eight teeth, (5) in profile, most hairs on cephalic dorsum short, length of most hairs <0.2× MOD, (6) in dorsal view, longitudinal rugae on mesonotum weakly to strongly irregular, often nearly rugoreticulate; rugae on pronotum usually rugoreticulate-vermiculate, (7) interrugae on promesonotum usually moderately to strongly granulate, weakly dull to dull, (8) superior propodeal spines consist of short to long spines for at least some workers in a series, and (9) in profile, rugae posterior to eyes fine, dense, regular, converging at or near posterior corners; interrugae, smooth and shining to moderately coriarious, weakly shining, rarely with a beaded appearance ( Figure 29 ).

Measurements — lectotype (n = 22). HL 1.74 (1.58–2.03); HW 1.87 (1.67–2.04); MOD 0.40 (0.36–0.44); OMD 0.50 (0.42–0.62); SL 1.37 (1.19–1.47); PNW 1.25 (1.15–1.42); HFL 1.64 (1.75–2.00); ML 2.44 (2.01–2.76); PW 0.52 (0.45–0.57); PPW 0.69 (0.60–0.75). Indices: SI 73.26 (63.73–83.83); CI 107.47 (93.82–117.72); OI 21.39 (18.27–25.15); HFI 87.70 (92.16–110.18).

Redescription. Head variable, from longer than wide to wider than long (CI = 93.82–117.72); posterior margin flat to weakly concave in full-face view. Longitudinal rugae on cephalic dorsum prominent, weakly wavy to irregular. In full-face view, medial rugae diverging toward posterior corners of head. Interrugae on cephalic dorsum strongly granulate-punctate, dull to weakly shining; posterior corners rugose, interrugae smooth and shining to weakly granulate, weakly shining. In profile, rugae posterior to eyes fine, dense, regular, converging at or near posterior corners; interrugae smooth and shining to moderately coriarious, weakly shining, rarely with a beaded appearance. Anterior margin of clypeus moderately concave, dorsum with several subparallel longitudinal rugae. Numerous long, curved, bristle-like, yellowish macrochaetae project from anterior margin of clypeus and basolateral margins of mandibles. Mandibles with six to seven, sometimes eight teeth (46% with six teeth, 43% with seven teeth, 11% with eight teeth, n = 37), one tooth occasionally as a denticle on one or both mandibles between tooth four and five; mandibular dorsum coarsely rugose. MOD ranging from 0.18–0.24× HL. In profile, eyes situated near middle of head, OMD = 1.0–1.7× MOD. In full-face view, eyes protruding slightly beyond lateral margins of head. Antennal scapes (SI = 63.73–83.83) failing to reach posterior corners of head by less than length of basal funicular segment. Antennal scapes with or without weak longitudinal striae, weakly to moderately granulate, weakly shining; basal flange well developed with carinate margin. Psammophore well developed.

Mesosomal profile weakly convex; all mesosomal surfaces with prominent subparallel-parallel, wavy to irregular rugae. In dorsal view, humeral shoulders of pronotum enlarged, dorsolateral margin weakly to distinctly angulate, especially in profile. In dorsal view, longitudinal rugae on mesonotum weakly to strongly irregular, often nearly rugoreticulate; rugae on pronotum usually rugoreticulate-vermiculate, irregular to rugoreticulate on pronotal sides; rugae on mesopleura angle posterodorsally. Promesonotal suture weakly to moderately impressed in a moderate number of workers. Superior propodeal spines consist of tubercles, denticles, short teeth, moderately long spines, or rarely long spines, spines usually connected by well defined keel; irregular transverse rugae on dorsum of propodeum traverse anteroventrally on sides. Inferior propodeal spines well developed, wider than high, apex blunt to subacute. Propodeal spiracles narrowly ovate facing posterad. Interrugae on mesosoma densely granulate, dull to weakly shining. Legs weakly shining to shining.

Peduncle of petiole about 0.8× as long as petiolar node, anteroventral margin flat or with a weak convex process. In profile, posterior surface of petiolar node weakly convex; node asymmetrical with anterior surface shorter than posterior surface, apex angulate. In dorsal view, petiolar node longer than wide, widest near spatulate anterior margin, narrowing posterad. Sides and posterior surface of petiolar node with wavy to irregular transverse rugae. Dorsum of postpetiole convex in profile; in dorsal view, widest near posterior margin, narrowing anterad, maximum width and length about equal. Wavy to irregular transverse rugae on dorsum of postpetiole finer, denser, than those on posterior surface of petiolar node; interrugae on both surfaces moderately coriarious, dull to weakly shining. First gastral tergum with striae over anterior one-half or more of segment, striae often extending to posterior margin of segment or with posterior margin strongly coriarious, dull.

Erect, mostly short, whitish pilosity moderately abundant on head, length of most hairs <0.2× MOD, often one to few long hairs that exceed MOD. Moderately abundant suberect to semidecumbent pilosity on scape; abundant decumbent hairs on funicular segments. Legs with moderately abundant suberect to decumbent whitish setae. Rest of body with erect, moderately dense, medium-length, whitish setae. Head, mesosoma, petiolar node, postpetiole black; gaster dark ferruginous orange to orangish-black with darker bands along posterior margin of terga ( Figure 29 ).

Queen diagnosis. Queens of this species are diagnosed by the following combination of features: (1) castespecific morphology of the mesosoma related to wing-bearing and presence of small ocelli, (2) striae cover more than anterior one-half of first gastral tergum, (3) head and mesosoma black, gaster (including posterior margin of terga) concolorous ferruginous orange, and (4) longest hairs along posterior margin of first and second gastral terga notably longer than MOD ( Figure 30 ).

Measurements —(n = 3). HL 1.90–1.97; HW 2.03–2.16; MOD 0.42–0.46; OMD 0.42–0.67; SL 1.41–1.49; PNW 1.60–1.63; HFL 1.80–2.06; ML 2.91–2.96; PW 0.54–0.66; PPW 0.82–0.91. Indices: SI 65.58–73.40; CI 106.84–113.09; OI 20.47–21.30; HFI 83.33–100.00.

Description. With caste-specific morphology of the mesosoma related to wing-bearing and presence of ocelli on head. In full-face view, head subquadrate to wider than long (CI = 106.84–113.09), widest just posterior to eyes, posterior margin flat. Longitudinal rugae on cephalic dorsum prominent, wavy. In full-face view, medial rugae weakly diverging toward posterior corners of head; posterior corners rugose, interrugae on cephalic dorsum and posterior corners moderately granulate-punctate, weakly shining. Mandibles with seven to eight teeth (seven on one mandible, eight on the other), dorsal surface coarsely rugose. Psammophore well developed.

All mesosomal surfaces except pronotal sides with subparallel, regular to wavy rugae, rugae irregular to rugoreticulate on pronotal sides; interrugae weakly to moderately granulate-punctate, weakly shining; superior propodeal spines minute, acuminate; inferior propodeal spines moderately well developed, wider than tall, acuminate. Peduncle of petiole about 0.8× as long as petiolar node, ventral margin flat. In profile, petiolar node asymmetrical with anterior surface shorter than posterior surface, apex angulate, anterior margin with a small crest. Posterior surface of petiolar node with wavy to irregular transverse rugae, crest along anterior margin weakly concave medially. In dorsal view, dorsum of postpetiole slightly wider than long; dorsum with wavy, transverse rugae that are finer, denser than those on posterior surface of petiolar node; interrugae on posterior surface of petiolar node and dorsum of postpetiole weakly granulate-punctate, weakly shining. Striae extend over more than anterior one-half of first gastral tergum. Most body surfaces with moderately abundant suberect to erect, short to long, yellowish setae, longest hairs on head and mesosoma> MOD; longest hairs along posterior margin of first and second gastral terga notably> MOD. Head, mesosoma, peduncle of petiole black; petiolar node blackish-orange; postpetiole dark ferruginous orange; gaster (including posterior margin of terga) concolorous ferruginous orange ( Figure 30 ).

Male diagnosis. Males of this species are diagnosed by the following combination of features: (1) striae extend over more than anterior one-half of first gastral tergum, (2) in dorsal view, rugae on cephalic dorsum posterior to eyes longitudinal, subparallel-parallel, continuing to posterior margin, (3) anterior one-half or more of anepisternum and usually katepisternum smooth and shining; subparallel-parallel, longitudinal rugae present posterad, (4) bicolored: head and mesosoma black, gaster ferruginous orange to dark orange, (5) larger: HW = 1.34–1.44 mm, PW = 0.58–0.68 mm, PPW = 0.79–0.84 mm, (6) rugae on posterior surface of petiolar node and dorsum of postpetiole usually regular or wavy to moderately irregular, (7) interrugae on mesoscutum, mesoscutellum, posterior surface of petiolar node, and dorsum of postpetiole usually mostly smooth and shining ( Figure 31 ).

Measurements —(n = 5). HL 1.35–1.48; HW 1.34–1.44; MOD 0.48–0.53; OMD 0.15–0.28; SL 0.40–0.47; HFL 1.82–1.97; ML 2.68–2.87; PW 0.58–0.66; PPW 0.79–0.84. Indices: SI 28.78–34.33; CI 93.92–106.67; OI 35.25–37.41; HFI 129.86–141.73.

Additional material examined. ARGENTINA: Chubut: Rt 25 at 91.7 km W Paso de Indios, 2610’, Feb 22, 2014 ( MCZC; RAJC) . Mendoza: Rt 145 at 25.1 km W Bardas Blancas, 4830’, Jan 26, 2008 ( LACM; MACN; MCZC; RAJC; UCDC; USNM) ; Rt 145 at 33.8 km W Bardas Blancas, 5010’, Jan 25, 2008 ( IFML; RAJC) . Neuqu é n: 6 km S Laguna Blanca, 4600’, Dec 7, 2003 ( CASC; MCZC; RAJC) ; Rt 46 at 8.5 km SW Zapala, 3530’, Feb 10, 2011 ( RAJC) ; Rt 242 at 34.3 km SW Las Lajas, 3970’, Feb 27, 2014 ( MCZC; RAJC) ( Figure 32A ).

Etymology. The name of this species, catanlilensis , was derived from Gallardo collecting the syntype series either near the Catán Lil River or in Departamento Catán Lil, Neuquén Province, Argentina.

Discussion. Pogonomyrmex catanlilensis is likely to co-occur with several P. rastratus -group species, but its coloration (black head and mesosoma and light to dark ferruginous orange gaster) and striae that cover the anterior one-half or more of the first gastral tergum distinguish it from all congeners except P. forelii , P. granulatus , and P. varicolor . Pogonomyrmex catanlilensis is separated from P. granulatus by: (1) superior propodeal spines variable, consisting of tubercles, denticles, and short teeth to long spines, (2) relatively large (HW = 1.67–2.04 mm; PNW = 1.15–1.42 mm; ML = 2.01–2.76 mm), (3) in profile, most hairs on cephalic dorsum short, length of most hairs <0.2× MOD, and (4) mandibles with six to eight teeth (> 50% with seven to eight teeth). For P. granulatus : (1) superior propodeal spines consist of tubercles, denticles, or short blunt teeth, but never moderately long to long spines, (2) relatively small (HW = 1.42–1.70 mm; PNW = 0.96–1.14 mm; ML = 1.67–2.12 mm), (3) in profile, most hairs on cephalic dorsum moderately long, length of numerous hairs> 0.4× MOD, and (4) mandibles with six teeth. Pogonomyrmex catanlilensis is distinguished from P. forelii by: (1) superior propodeal spines variable, consisting of tubercles, denticles, and short teeth to long spines, and (2) rugae on anterodorsal margin of pronotum longitudinal, oblique, or rugoreticulate for most workers in a series. For P. forelii : (1) superior propodeal spines moderately long to long, and (2) one to several transverse (sometimes very irregular) rugae present on anterodorsal margin of pronotum for most workers in a series. Pogonomyrmex catanlilensis is separated from P. varicolor by: (1) larger (HW = 1.67–2.04 mm; PNW = 1.15–1.42 mm; ML = 2.01–2.76 mm), (2) in dorsal view, longitudinal rugae on mesonotum weakly to strongly irregular, often nearly rugoreticulate; rugae on pronotum usually rugoreticulate-vermiculate, and (3) interrugae on promesonotum usually moderately to strongly granulate, weakly dull to dull. For P. varicolor : (1) smaller (HW = 1.48–1.79 mm; PNW = 0.98–1.18 mm; ML = 1.56–2.07 mm), (2) in dorsal view, rugae on promesonotum regular to wavy, longitudinal rugae on mesonotum continue to anterodorsal margin of pronotum or diverge to humeral shoulders of pronotum with one to few transverse rugae along anterodorsal margin, and (3) interrugae on promesonotum smooth and shining to moderately granulate, weakly shining.

Pogonomyrmex catanlilensis displays morphological variation among populations. For example, compared to other series, workers from 91.7 km west of Paso de Indios, Chubut Province, were generally larger, their superior propodeal spines were reduced to tubercles or denticles, and their promesonotal suture was sometimes impressed.

Biology. Pogonomyrmex catanlilensis workers are solitary foragers. Nests of P. catanlilensis typically are placed in a clump of Stipa sp. (Poaceae) , at the base of a small shrub, or under a rock; one nest had two entrances, one in the open and one in a clump of Stipa sp. The nest entrance is surrounded by a tumulus up to 10–15 cm in diameter. Nests are most easily located by baiting workers with cookie crumbs, then following them back to the nest. Partial nest excavations indicated that colonies contain up to approximately 2000 workers. Sexuals have been collected from 25 January–27 February indicating that mating flights occur during the austral summer.

Pogonomyrmex catanlilensis inhabits elevations from 790–1520 m in the Southern Andean steppe and Patagonian steppe ecoregions, as per Olson et al. (2001) ( Figure 32A ).

Figures

FIGURE 29. Photographs of Pogonomyrmex catanlilensis worker: (A) frontal view of head, (B) lateral view of body, and (C) dorsal view of body (CASENT0102695). Photographs by April Nobile from www.AntWeb.org.

FIGURE 30. Photographs of Pogonomyrmex catanlilensis alate queen: (A) frontal view of head, (B) lateral view of body, and (C) dorsal view of body (CASENT0235276). Photographs by Will Ericson from www.AntWeb.org.

FIGURE 31. Photographs of Pogonomyrmex catanlilensis male: (A) frontal view of head, (B) lateral view of body, and (C) dorsal view of body (CASENT0914362). Photographs by Michele Esposito from www.AntWeb.org.

FIGURE 32. Geographic distribution of: (A) Pogonomyrmex catanlilensis, and (B) P. colca, and (C) P. cusquena. The large black circle in each panel denotes the type locality.