Pheidole petax

The species was collected between 64–1343 m in elevation, in rainforest, montane rainforest, transitional humid forest, an urban garden, and grassland. Nests were located in rotten logs and tree stumps, and in dead twigs above ground.

Identification
Salata and Fisher (2020) - Major: Head in full-face view rectangular, anterior and posterior of eyes relatively straight; sides of head with sparse, short, decumbent pilosity; scrobe surface with dense, fine rugulae and sometimes with additional sparse and fine, longitudinal rugae, interspaces and rugulae finely foveolate; inner hypostomal teeth distinct, big, thick, triangular, with rounded apex; outer hypostomal teeth approximately as high as inner hypostomal teeth but thinner, triangular, with rounded tips and wide base; first gastral tergite shagreened, at least on its basal part; body brown to dark brown. Minor:. Head foveolate, only genae with smooth notches, covering at least their central part; promesonotum slightly convex, with relatively steep posterior declivity; mesosoma foveolate, only katepisternum and sometimes lateral sides of propodeum smooth; propodeal spines very short and triangular; body yellowish brown.

This species in most similar to Pheidole brevipilosa and Pheidole glabra. Major workers. Pheidole petax can be distinguished from P. brevipilosa and P.  glabra by never erect pilosity on sides of head, and more rectangular head shape in full-face view. Minor workers. Pheidole petax can be distinguished from P. brevipilosa by yellowish brown body colouration, lack of additional indistinct, longitudinal rugae on frons and malar area, lack of additional sparse, irregular rugae on promesonotal dorsum, and foveolate clypeus; from P.  glabra by yellowish brown body colouration, sparser pilosity on head, lack of additional indistinct, longitudinal rugae on frons and malar area, never reduced or absent sculpture on the central part of frons, and dorsal surface of pronotum with never reduced sculpture.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  petax. Pheidole nemoralis var. petax Forel, 1895h: 488 (s.w.) MADAGASCAR.
 * Status as species: Salata & Fisher, 2020: 174.

Worker
Salata and Fisher (2020) - Major (N = 10): HL: 1.37-1.6 (1.52); HW: 1.22-1.48 (1.4); SL: 0.56-0.64 (0.59); EL: 0.13-0.19 (0.16); WL: 1.08-1.24 (1.17); PSL: 0.21-0.24 (0.23); MTL: 0.57-0.66 (0.61); PNW: 0.72-0.88 (0.79); PTW: 0.18-0.25 (0.21); PPW: 0.61-0.75 (0.69); CI: 88.8-96.0 (91.7); SI: 40.3-45.6 (42.5); PSLI: 14.1-16.1 (15.0); PPI: 28.5-34.0 (30.7); PNI: 53.3-59.6 (56.7); MTI: 40.5-46.8 (43.9). Head. In full-face view rectangular, anterior and posterior of eyes relatively straight. In lateral view sub-rectangular; ventral and dorsal faces finely convex; dorsal face finely depressed posteriorly, forming shallow transverse depression between frons and occipital lobes; inner hypostomal teeth visible. Sides of head with sparse, short, decumbent pilosity; whole head with moderately dense, short, decumbent to erect pilosity. Antennal scrobes indistinct and not delimited by carinulae. Occipital lobes with thick, sparse, irregular rugae, interspaces smooth and shiny; frons with thick, sparse to moderately sparse, longitudinal rugae, interspaces variable, smooth to finely foveolate; malar area and lateral sides of head with dense, fine rugulae and sometimes with additional sparse and fine, longitudinal rugae, interspaces and rugulae finely foveolate; genae with very fine and dense rugulae, sometimes rugulae weakening posteriorly or absent. Clypeus shiny and smooth, with a few indistinct, longitudinal rugae on the lateral sides; median notch present, wide, and shallow; median longitudinal carina absent; lateral longitudinal carinae absent. Scape, when laid back, reaching slightly beyond midlength of head; pilosity decumbent to erect. Inner hypostomal teeth distinct, big, thick, triangular, with rounded apex; outer hypostomal teeth approximately as high as inner hypostomal teeth but thinner, triangular, with rounded tips and wide base. Mesosoma. In lateral view, promesonotum short, angular and relatively low, posterior mesonotum convex or slightly steep, without projections; promesonotal groove absent; metanotal groove absent; propodeal spines small, with base wide, apex rounded; humeral area with wide and flat tubercles. Pronotum shiny, with sparse, irregular, thin rugae, interspaces smooth to finely foveolate; mesonotum and anepisternum finely foveolate; katepisternum smooth; propodeum finely foveolate and sometimes with additional rugae. Pilosity moderately dense, long, and erect. Petiole. Shiny; peduncle finely foveolate, without horizontal lobes on its basal part; node smooth, moderately high and narrow, with convex apex, in rear view node dorsoventrally concave; pilosity moderately dense and erect. Postpetiole. Finely foveolate and shiny; in dorsal view sides with moderately long, acute, narrow, and horn-like projections; pilosity long, moderately dense, and erect. Petiole. First gastral tergite shagreened, at least on its basal part; pilosity dense, moderately short, and erect. Colour. Brown to dark brown, legs yellow to bright 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: 0.53-0.58 (0.55); HW: 0.48-0.51 (0.49); SL: 0.47-0.53 (0.5); EL: 0.09-0.12 (0.11); WL: 0.6-0.69 (0.67); PSL: 0.07-0.09 (0.06); MTL: 0.37-0.44 (0.4); PNW: 0.29-0.36 (0.32); PTW: 0.05-0.08 (0.07); PPW: 0.11-0.16 (0.14); CI: 86.7-93.6 (89.5); SI: 98.2-103.8 (101.5); PSLI: 12.6-16.7 (14.4); PPI: 41.5-58.8 (49.4); PNI: 61.3-70.0 (65.8); MTI: 76.4-88.2 (82.2). Head. Occipital margin straight or indistinctly concave; occipital carina indistinct, weakly developed. Pilosity moderately dense, moderately long, decumbent to erect. Whole head foveolate, only genae with smooth notches covering at least their central part. Clypeus shiny, foveolate; median longitudinal carina present; two lateral longitudinal carinae absent. Scape, when laid back, surpassing the posterior head margin by two-fifths of its length; pilosity suberect to erect. Mesosoma. In lateral view, promesonotum slightly convex, with relatively steep posterior declivity; promesonotal groove absent; metanotal groove indistinct; propodeal spines very short and triangular, apex acute. Sculpture foveolate, only katepisternum and sometimes lateral sides of propodeum smooth. Pilosity moderately sparse, long, and erect. Petiole. Peduncle short and thin with ventral face slightly convex; node low, globular, and small; with few long, erect setae. Postpetiole. Short, low, and slightly convex; with few short, erect setae. Petiole. With sparse, erect pilosity. Colour. Unicolourous, yellowish 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

 * Lectotype (designated by Salata & Fisher, 2020): major worker (CASENT0101321): Madagascar, Central Madagascar, coll. Sikora [examined].
 * Paralectotype: 1 minor worker (the same pin as lectotype, CASENT0101322) (MHNG) [examined]: the same data as lectotype.