Pheidole ferruginea

The species was collected between 20–1312 m in elevation, in rainforest, montane rainforest, and littoral rainforest. Nests were located in rotten logs and tree stumps, rotten sticks on ground, and the petioles of Melastomataceae.

Identification
Salata and Fisher (2020) - Head in full-face view cordate, widened posteriorly; sides of the head with sparse, long, suberect pilosity; antennal scrobes strongly developed, well delimited and forming distinct dorsal concavity beneath frontal carina; scrobe surface shiny, with sparse, thick, longitudinal and sometimes additional irregular rugae; delimited ventrally and posteriorly by carinulae; propodeal spines long (PSL: 0.23-0.28 (0.26)); first gastral tergite shagreened, at least on its basal part. Minor: Head foveolate, sometimes with additional longitudinal rugae on frons; propodeal spines very long (PSL: 0.15-0.18 (0.16)); promesonotum box-like; mesosoma foveolate, sometimes with additional rugae on mesosomal dorsum, and katepisternum with smooth notch.

This species is most similar to Pheidole rugocephala. Major workers. Pheidole ferruginea can be distinguished from P. rugocephala by the surface of antennal scrobes never foveolate; presence of longitudinal rugae on frons; inner hypostomal teeth newer pointed inward; never smooth surface of promesonotum; and lack of horizontal lobes on the basal part of petiolar peduncle. Minor workers. Pheidole ferruginea can be distinguished from P. rugocephala by long propodeal spines and foveolate clypeus, and lack of promesonotal and metanotal grooves.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  ferruginea. Pheidole ferruginea Salata & Fisher, 2020: 92, figs. 35A–F, 84P, 86P (w.) MADAGASCAR.

Worker
Major (N = 10): HL: 1.18-1.34 (1.25); HW: 1.15-1.31 (1.23); SL: 0.61-0.69 (0.64); EL: 0.13-0.17 (0.15); WL: 0.93-1.05 (0.99); PSL: 0.23-0.28 (0.26); MTL: 0.58-0.66 (0.61); PNW: 0.5-0.6 (0.53); PTW: 0.13-0.17 (0.16); PPW: 0.45-0.58 (0.51); CI: 97.4-101.3 (99.0); SI: 48.7-55.8 (52.1); PSLI: 18.9-21.9 (20.8); PPI: 27.5-33.7 (30.7); PNI: 40.9-45.0 (43.0); MTI: 47.6-52.2 (49.7). Head. In full-face view cordate, widened posteriorly. In lateral view oval; ventral and dorsal faces strongly convex; inner hypostomal teeth visible. Sides of the head with sparse, long, suberect pilosity; whole head with moderately dense, long, suberect to erect pilosity. Antennal scrobes strongly developed, well delimited and forming distinct dorsal concavity beneath frontal carina, scrobe surface shiny, with sparse, thick, longitudinal, and sometimes additional irregular rugae, delimited ventrally and posteriorly by carinulae. Occipital lobes shiny, with sparse and thick rugoreticulation; genae shiny, with moderately dense to dense, fine rugoreticulation; frons and malar area with sparse, thick, and longitudinal rugae, interspaces smooth or with fine rugulae. Centre of clypeus smooth and shiny, lateral sides with longitudinal rugae; median notch present, narrow, and shallow; median longitudinal carina present but sometimes indistinct; lateral longitudinal carinae absent. Scape, when laid back, reaching slightly beyond the midlength of head; pilosity decumbent to erect. Inner hypostomal teeth distinct, closely spaced, triangular, with rounded apex and moderately narrow base; outer hypostomal teeth distinct, slightly lower than inner hypostomal teeth, lobe-like, with base wide and tops directed slightly inward. Mesosoma. In lateral view, promesonotum short, angular, and moderately high, posterior mesonotum with tubercle-like projection, dropping steeply to propodeum; promesonotal groove absent; metanotal groove absent; propodeal spines long, massive basally, with acute apex; humeral area laterally weakly produced. Surface shiny, with thick and dense rugoreticulation, sometimes sculpture weakening on dorsum. Pilosity moderately sparse, long, and erect. Petiole. Shagreened; peduncle relatively long, without horizontal lobes on its basal part; node low, triangular, with rounded apex, in rear view node slightly convex; pilosity moderately sparse and erect. Postpetiole. Shagreened; in dorsal view sides with acute, triangular, moderately long projections; pilosity long, moderately sparse, and erect. Petiole. First gastral tergite shagreened, at least on its basal part; pilosity moderately sparse, long, and erect. Colour. Head and mesosoma reddish brown to brown; dorsum of mesosoma dark brown; gaster brown; legs yellow to brown.

Unless otherwise noted above, the following characters occur in this species, and the majority of Pheidole majors of Madagascar described by Salata and Fisher 2020a. Antennal sockets shallow; frontal lobes absent; head in full-face view with distinct median concavity; antenna 12-segmented, with 3-segmented club; masticatory margin of mandible with large, stout apical and preapical teeth, followed by a long diastema and then a short and crenulate tooth just before the rounded basal angle; outer surface of mandible mostly smooth and shining, sometimes with weak and sparse foveolae; antennal scrobes present; promesonotum strongly convex, well above the level of propodeum; postpetiole short with slightly convex dorsum; ventral process absent.

Minor (N = 10): HL: 0.52-0.57 (0.55); HW: 0.44-0.48 (0.46); SL: 0.57-0.63 (0.6); EL: 0.11-0.13 (0.12); WL: 0.67-0.72 (0.7); PSL: 0.15-0.18 (0.16); MTL: 0.44-0.49 (0.46); PNW: 0.31-0.35 (0.33); PTW: 0.07-0.09 (0.08); PPW: 0.13-0.14 (0.13); CI: 80.9-86.2 (83.9); SI: 124.6-134.8 (130.0); PSLI: 27.5-31.4 (29.3); PPI: 57.4-67.9 (63.1); PNI: 69.6-74.8 (71.7); MTI: 96.9-102.3 (100.9). Head. Occipital margin straight or indistinctly concave; occipital carina absent. Pilosity sparse, long, suberect to erect. Whole head foveolate, sometimes with additional longitudinal rugae on frons. Clypeus foveolate; median longitudinal carina absent; two lateral longitudinal carinae absent. Scape, when laid back, surpassing posterior head margin by two-fifths of its length; pilosity suberect to erect. Mesosoma. In lateral view, promesonotum box-like; promesonotal groove absent; metanotal groove absent; propodeal spines very long, massive basally, with acute apex. Whole surface foveolate, sometimes with additional rugae on mesosomal dorsum; sometimes katepisternum with smooth notch. Pilosity sparse, long, and erect. Petiole. Peduncle relatively long and thin; node low, globular; with few long, erect setae. Postpetiole. Short, low, and convex; with few long, erect setae at the anterior edge. Petiole. Pilosity sparse and erect. Colour. Unicolourous, yellow to brown.

Unless otherwise noted above, the following characters occur in this species, and the majority of Pheidole minors of Madagascar described by Salata and Fisher 2020a. Antennal sockets shallow; frontal lobes absent; head in full-face view oval, posterior and anterior of eyes convex; antenna 12-segmented, with 3-segmented club; humeral area not developed; clypeus smooth and shiny; its anterior margin regularly convex; promesonotum well above the level of propodeum; petiole smooth; petiole with node moderately low, triangular and small postpetiole smooth; gaster smooth and shiny.

Type Material
Holotype. Madagascar. •1 major worker; Antsiranana; Parc National de Marojejy, Manantenina River, 27.6 km 35°NE Andapa, 9.6 km 327°NNW Manantenina; -14.435, 49.76; alt. 775 m; 16 Nov 2003; B.L. Fisher leg.; BLF08998, CASENT0494997, middle specimen on the pin. Paratypes. Madagascar. •9w., 5s.; same data as for holotype; CASENT0494993-CASENT0494996, CASENT0872087, CASENT0872230-CASENT0872238 (CASC).

Etymology
Latin for rusty, in reference to body colouration of major workers.