Pheidole rugocephala

The species was collected between 15–1200 m in elevation, in rainforest, montane rainforest, and littoral rainforest. Nesting preferences unknown.

Identification
Salata and Fisher (2020) - Major: Head in full-face view cordate, widened posteriorly; sides of the head with moderately dense, long, suberect to erect pilosity; antennal scrobes present, strongly developed, well delimited and forming distinct dorsal concavity beneath frontal carina; scrobe surface foveolate; delimited ventrally and posteriorly by carinulae; propodeal spines long (PSL: 0.13-0.2 (0.15)); first gastral tergite shagreened on its basal part. Minor:. Head foveolate; propodeal spines long (PSL: 0.09); promesonotum box-like; mesosoma foveolate; katepisternum with smooth notch.

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

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Worker
Minor

Major

Nomenclature

 *  rugocephala. Pheidole rugocephala Salata & Fisher, 2020: 98, figs. 36A–F, 85U, 88E (w.q.) MADAGASCAR.

Worker
Major (N = 10): HL: 0.86-1.18 (0.97); HW: 0.87-1.12 (0.93); SL: 0.42-0.52 (0.45); EL: 0.12-0.14 (0.13); WL: 0.72-0.99 (0.82); PSL: 0.13-0.2 (0.15); MTL: 0.43-0.51 (0.45); PNW: 0.47-0.62 (0.53); PTW: 0.13-0.19 (0.14); PPW: 0.35-0.53 (0.41); CI: 95.3-101.3 (97.5); SI: 46.0-50.9 (48.2); PSLI: 14.3-17.0 (15.7); PPI: 30.9-36.9 (33.6); PNI: 53.7-59.9 (56.4); MTI: 45.5-52.3 (48.5). Head. In full-face view cordate, widened posteriorly. In lateral view oval; ventral face convex; dorsal face relatively flat; inner hypostomal teeth visible. Sides of the head with moderately dense, long, suberect to erect 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 foveolate, delimited ventrally and posteriorly by carinulae. Occipital lobes shiny, with sparse and thick rugae, sculpture weakening posteriorly; frons and malar area with thick, sparse, longitudinal or irregular rugae, interspaces smooth; genae with dense and fine rugulae. Centre of clypeus smooth and shiny, lateral sides with longitudinal rugae; median notch present, narrow, and shallow; median longitudinal carina absent; lateral longitudinal carinae present. 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 pointed inward; outer hypostomal teeth distinct, slightly higher than inner hypostomal teeth, lobe-like, with base wide and acute tops directed outward; inner and outer teeth closely spaced and connected by concavity. 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, with narrow base and acute apex; humeral area laterally weakly produced. Surface shiny, with sparse rugoreticulation, dorsum with weaker sculpture and sometimes smooth patches. Pilosity moderately sparse, long, and erect. Petiole. Finely foveolate; peduncle relatively long, with horizontal, triangular lobes on its basal part; node high, triangular, with rounded apex, in rear view node dorsoventrally depressed; pilosity moderately sparse and erect. Postpetiole. Finely foveolate; short; in dorsal view sides with acute, very wide, and long triangular projections; pilosity long, moderately dense and erect. Petiole. First gastral tergite shagreened on its basal part; pilosity moderately dense, very long and erect. Colour. Head and mesosoma reddish brown to 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 = 1): HL: 0.48; HW: 0.43; SL: 0.42; EL: 0.09; WL: 0.6; PSL: 0.09; MTL: 0.35; PNW: 0.3; PTW: 0.08; PPW: 0.14; CI: 89.4; SI: 99.1; PSLI: 18.6; PPI: 58.6; PNI: 69.2; MTI: 82.2. Head. Occipital margin straight or indistinctly concave; occipital carina absent. Pilosity sparse, long, suberect to erect. Whole head foveolate. Clypeus with median longitudinal carina absent; two lateral longitudinal carinae absent. Scape, when laid back, surpassing posterior head margin by one-fifth of its length; pilosity suberect to erect. Mesosoma. In lateral view, promesonotum box-like; promesonotal groove present; metanotal groove present; propodeal spines moderately long, triangular, with acute apex. Whole surface foveolate, only katepisternum with smooth notch. Pilosity sparse, long and erect. Petiole. Shiny; peduncle foveolate, short and thin; node finely foveolate, globular; with few long, erect setae. Postpetiole. Finely foveolate with smooth centre; short, low and convex; with few long, erect setae at the anterior edge. Petiole. With few long, erect setae. Colour. Unicolourous, yellow.

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; Toamasina; 6.9 km NE Ambanizana, Ambohitsitondroina; -15.58506, 50.00952; alt. 825 m; 2 Dec 1993; B.L. Fisher leg.; BLF00976, CASENT0923224. Paratypes. Madagascar. 1w., 1q.; same data as for holotype; CASENT0198470, CASENT0872239 (CASC).

Etymology
Latin for strong and distinct head sculpture on major workers.