Pogonomyrmex cusquena, Johnson, 2021

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 : 76-79

Pogonomyrmex cusquena NEW SPECIES

( Figures 7B , 34 )

Distribution—32C

Holotype worker [ MUSM: CASENT0922566 ]: PERU, Cusco Region: Moray Valle Sagrado (see below), 13º19.8’S 72º11.8’W, 3000 m, 2 May 2007 (Alain Lenoir, unnumbered) . Paratypes, same data as holotype: CPDC (1w) , MCZC (1w) , RAJC (1w), USNM (1w).

Worker diagnosis. Workers of this species are uniquely characterized by the following combination of features: (1) first gastral tergum smooth and shining, sometimes weakly coriarious anterad, (2) superior propodeal spines consist of acuminate denticles to short teeth, length usually similar to or less than that of inferior propodeal spines, (3) in profile, lateral portion of head from posterior margin of eyes to posterior corners faintly rugose to mostly smooth and shining, rugae weakening posterad, posterior corners smooth and shining to strongly shining, (4) longitudinal rugae on promesonotum regular to moderately irregular with few lateral branches, (5) promesonotal suture usually weakly to moderately impressed, and (6) rugae present on posterior surface of postpetiole ( Figures 7B , 34 ).

Measurements — holotype (n = 4 paratypes). HL 1.51 (1.50–1.61); HW1.52 (1.51–1.66); MOD 0.30 (0.32– 0.35); OMD 0.40 (0.38–0.43); SL 1.19 (1.12–1.30); PNW 1.05 (1.02–1.12); HFL 1.56 (1.46–1.65); ML 1.68 (1.80– 1.95); PW 0.37 (0.41–0.42); PPW 0.56 (0.55–0.57). Indices: SI 78.29 (74.17–79.87); CI 100.66 (100.00–103.11); OI 19.74 (19.28–22.01); HFI 102.63 (93.98–100.61).

Description. Head quadrate to slightly wider than long (CI = 100.00–103.11); posterior margin flat in full-face view. Longitudinal rugae on cephalic dorsum prominent, regular to wavy; in full-face view, medial rugae continuing to posterior margin. Interrugae on cephalic dorsum weakly to moderately granulate, weakly shining; in profile, lateral portion of head from posterior margins of eyes to posterior corners faintly rugose, rugae weakening posterad, posterior corners smooth and shining to strongly shining. Anterior margin of clypeus moderately concave, dorsum with numerous subparallel, longitudinal rugae; interrugae smooth and shining. Numerous long, curved, bristle-like, yellowish macrochaetae project from anterior margin of clypeus and basolateral margin of mandibles. Mandibles with six teeth; mandibular dorsum coarsely rugose. MOD ranging from 0.19–0.22× HL. In profile, eyes situated slightly anterior to middle of head, OMD = 1.08–1.35× MOD. In full-face view, eyes protruding slightly beyond lateral margins of head. Antennal scapes (SI = 74.17–79.87) failing to reach posterior corners of head by less than length of basal funicular segment, scapes smooth and shining to weakly striate, interstriae weakly shining to smooth and shining. Basal flange well developed with carinate margin. Psammophore well developed.

Mesosomal profile weakly to moderately convex; all mesosomal surfaces with prominent, regular to weakly irregular, subparallel-parallel rugae. Rugae on dorsum of promesonotum well defined, regular to weakly irregular, subparallel, usually lacking lateral branches; longitudinal rugae on mesonotum continue onto pronotum, lateralmost rugae diverging onto humeral shoulders of pronotum and continuing ventrally on pronotal sides, medial rugae usually continue to anterior margin of pronotum or sometimes weakly rugoreticulate. In dorsal view, humeral shoulders of pronotum enlarged, dorsolateral margin angulate. Promesonotal suture weakly to moderately impressed. Regular to weakly irregular rugae on mesopleura angle posterodorsally or posterad; regular to wavy, transverse rugae on dorsum of propodeum traverse ventrally or anteroventrally on sides or oblique or longitudinal rugae that continue posterad to superior propodeal spines. Superior propodeal spines consist of acuminate denticles to short teeth, well defined keel connecting spines present or absent. Inferior propodeal spines wider than high, broadly triangular, tips bluntly rounded to subacute, height similar to or greater than length of superior propodeal spines. Propodeal spiracles narrowly ovate facing posterad. Interrugae on mesosoma smooth and shining to moderately granulatepunctate, weakly shining, pronotal sides and mesopleura usually more granulate than dorsal surface. Legs weakly to moderately coriarious, weakly shining to smooth and shining.

Peduncle of petiole about as long as petiolar node, anteroventral margin with a moderately well developed, broadly rounded process. In profile, posterior surface of petiolar node weakly convex; petiolar node asymmetrical with anterior surface notably shorter than posterior surface, apex subangulate. In dorsal view, petiolar node longer than wide, sides subparallel anterad, widest near spatulate anterior margin, narrowing slightly posterad. Sides and posterior surface of petiolar node with regular, transverse rugae. Dorsum of postpetiole convex in profile; in dorsal view, widest near posterior margin, narrowing anterad, maximum width and length similar; transverse to arcuate, regular to wavy rugae posterad, anterad rugae concentric and traversing medially from lateral margin then curving anterad to become longitudinal; rugae on dorsum of postpetiole finer, denser than those on posterior surface of petiolar node; interrugae on both surfaces smooth and shining. First gastral tergum smooth and shining, anterad portion sometimes weakly coriarious, weakly shining.

Erect, mostly short to medium length, whitish pilosity moderately abundant on head, most hairs <0.2–0.3× MOD. Moderately abundant suberect to semidecumbent pilosity on scape; abundant decumbent hairs on funicular segments. Legs with moderately abundant suberect to decumbent, yellowish setae. Rest of body with moderately dense, erect, medium-length, whitish to cream-colored hairs, longest hairs on dorsum of mesosoma approximately 0.4–0.5× MOD. Head ferruginous orange to reddish-orange; mesosoma, antennae darker reddish-orange; gaster, legs blackish with a moderate orangish infusion; petiolar node and postpetiole concolorous with mesosoma or gaster ( Figures 7B , 34 ).

Queen. Unknown.

Male. Unknown.

Additional material examined. None.

Etymology. The specific epithet, cusquena , is derived from the type workers being collected in the Cusco Region of Peru.

Discussion. Pogonomyrmex cusquena is distinguished from all congeners by the combination of: (1) psammophore well developed, (2) superior propodeal spines consist of acuminate denticles to short teeth, (3) first gastral tergum smooth and shining, sometimes weakly coriarious anterad, (4) in profile, lateral portion of head from posterior eye margin to posterior corners faintly rugose to mostly smooth and shining, rugae weakening posterad, posterior corners smooth and shining to strongly shining, and (5) rugae present on posterior surface of postpetiole ( Figure 34 ).

The type locality given above differs from the label, which reads Maray Vale Sagrado, Peru, 300 m, 2 May 2007, A. Lenoir. Both the location and elevation on the labels were problematic because there is no Maray in Vale Sagrado and the elevation of Vale Sagrado is approximately 3000 m. This issue was resolved by contacting Alain Lenoir, who indicated that the locality was probably the archaeological site Moray (not Maray) Valle Sagrado at an elevation of approximately 3000 m (A. Lenoir, pers. comm.).

Biology. Nothing is known about the biology of P. cusquena . Pogonomyrmex cusquena is only known from the type locality at approximately 3000 m elevation, which is in the Peruvian Yungas ecoregion and probably the Central Andean wet puna ecoregion, as defined by Olson et al. (2001) ( Figure 32C ).

Figures

FIGURE 7. Photographs showing rugae patterning on dorsum of promesonotum: (A) Pogonomyrmex colca (CASENT0923342) with longitudinal rugae on promesonotum strongly irregular with numerous lateral branches to rugoreticulate, and (B) Pogonomyrmex cusquena (CASENT0922566) with longitudinal rugae on promesonotum regular to moderately irregular with few lateral branches. Photographs by Robert Johnson 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.

FIGURE 34. Photographs of Pogonomyrmex cusquena holotype worker: (A) frontal view of head, (B) lateral view of body, and (C) dorsal view of body (CASENT0922566). Photographs by Michele Esposito from www.AntWeb.org.