Pheidole sparsa

The species was collected at 1606 m in elevation, in montane rainforest. Nests were located in rotten logs.

Identification
Salata and Fisher (2020) - A member of the Pheidole sikorae species group. Moderately large species. Major: Head in full-face view sub-oval, not widening posteriorly, with anterior and posterior sides relatively straight, in lateral view sub-oval; ventral and dorsal faces convex; sides of the head with dense, moderately long, suberect to erect pilosity; medial part of frons with moderately sparse, thick, longitudinal, and interrupted rugae, rugae in posteromedial slightly directed outward, interspaces shiny with sparse and indistinct rugofoveolae; anterolateral sides with longitudinal, thick, and relatively sparse rugae; posterolateral sides with irregular, thick, and relatively sparse rugae; interspaces shiny with sparse and indistinct rugofoveolae; occipital lobes and area posterolateral from eyes without smooth notches; scape, when laid back, exceeding the midlength of head by two-fifths of its length; inner hypostomal teeth distinct, large, closely spaced, triangular, with rounded apex directed upward; outer hypostomal teeth lobe-like, approximately the same height and width as inner hypostomal teeth, apex directed outward; inner and outer hypostomal teeth closely spaced and not connected by concavity; promesonotum predominantly smooth, with indistinct rugofoveolae on lateral sides; katepisternum rugofoveolate with smooth notch; propodeum rugofoveolate; gaster smooth; body dark orange. Minor: Head foveolate; medial part of frons with smooth notch and indistinct, short rugulae; area posterolateral from eyes predominantly smooth; scape, when laid back, surpassing the posterior head margin by one-fifth of its length; promesonotum moderately low and moderately long, arched; promesonotal groove absent; propodeal spines small and triangular; pronotum with very indistinct and sparse foveolae; mesonotum, anepisternum, katepisternum, and propodeum smooth; body dark yellow.

Pheidole sparsa, described from Bemanevika in Mahajanga, is most similar to Pheidole dasos, known from Makirovana forest in Antsiranana, and Pheidole hazo, recorded so far only from the vicinity of Andranoma in Antananarivo. Majors of P. sparsa can be distinguished from both taxa mentioned above by medial part of frons with moderately sparse rugae, interspaces with sparse and indistinct rugofoveolae, and predominantly smooth promesonotum with indistinct rugofoveolae on lateral sides; minors of P. sparsa can be distinguished from P. hazo by dark yellow body colouration and propodeum with indistinct and sparse foveolae, and from P. dasos by dark yellow body colouration, shorter scape surpassing the posterior head margin by one-fifth of its length, and pronotum with very indistinct and sparse foveolae.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 * . Pheidole sparsa Salata & Fisher, 2020: 147, figs. 55A–F, 64M, 67E (w.) MADAGASCAR.

Worker
Major (N = 4): HL: 0.94-1.13 (1.06); HW: 0.94-1.1 (1.04); SL: 0.61-0.72 (0.67); EL: 0.12-0.14 (0.13); WL: 0.93-1.0 (0.98); PSL: 0.16-0.2 (0.18); MTL: 0.6-0.65 (0.62); PNW: 0.41-0.5 (0.45); PTW: 0.14-0.18 (0.16); PPW: 0.27-0.32 (0.3); CI: 99.0-103.0 (101.7); SI: 62.7-65.5 (64.7); PSLI: 15.9-17.5 (16.7); PPI: 45.2-61.7 (53.9); PNI: 42.6-45.4 (43.6); MTI: 55.9-64.7 (59.4).

Head. In full-face view sub-oval, not widening posteriorly, with anterior and posterior sides relatively straight. In lateral view sub-oval; ventral and dorsal faces convex; inner hypostomal teeth visible. Sides of the head with dense, moderately long, erect pilosity; whole head with dense, long, decumbent to erect pilosity. Medial part of frons with moderately sparse, thick, longitudinal, and interrupted rugae, posteromedial rugae slightly directed outward, interspaces shiny with sparse and indistinct rugofoveolae; anterolateral sides with longitudinal, thick, and relatively sparse rugae; posterolateral sides with irregular, thick, and relatively sparse rugae; interspaces shiny with sparse and indistinct rugofoveolae. Occipital lobes with sparse, thick, and irregular rugae; interspaces smooth. Gena with relatively sparse, thick, and longitudinal rugae and smooth interspaces. Area posterolateral from eyes with thin and dense rugofoveolae and smooth interspaces. Centre of clypeus smooth and shiny, lateral sides with indistinct rugulae; median notch present, moderately wide, and shallow; median longitudinal carina absent; lateral longitudinal carinae absent. Scape, when laid back, exceeding the midlength of head by two-fifths of its length; pilosity subdecumbent to erect. Inner hypostomal teeth distinct, large, closely spaced, triangular, with rounded apex directed upward; outer hypostomal teeth lobe-like, approximately the same height and width as inner hypostomal teeth, apex directed outward; inner and outer hypostomal teeth closely spaced and not connected by concavity. Mesosoma. In lateral view, promesonotum short, angular, and moderately low, posterior mesonotum moderately steep, mesonotal process indistinct, tubercle-like; promesonotal groove absent; metanotal groove indistinct; propodeal spines moderately long, moderately narrow, with acute apex; humeral area laterally weakly produced. Surface shiny; promesonotum predominantly smooth, with indistinct rugofoveolae on lateral sides; katepisternum rugofoveolae with smooth notch; propodeum rugofoveolate. Pilosity relatively dense, long, and erect. Petiole. Shiny with fine and sparse rugofoveolae; node smooth, low, triangular, with rounded and thin apex, in rear view node dorsoventrally slightly convex; pilosity moderately sparse and erect. Postpetiole. Shiny and smooth; in dorsal view oval, lateral margins medially with two dentate projections; pilosity long, moderately sparse, and erect. Gaster. Shiny and smooth; pilosity moderately dense, long, and erect. Colour. Dark orange; mandibles and gaster slightly darker; legs yellowish.

The following characters are found in most Pheidole sikorae species-group majors in Madagascar (Salata and Fisher 2020b). These characters also occur in , except for any differences noted in the paragraph above. Dorsal face of head in lateral view not depressed posteriorly; 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 absent; promesonotum strongly convex, well above the level of propodeum; petiolar peduncle with small horizontal lobes on its basal part; postpetiole short with slightly convex dorsum; petiolar peduncle without horizontal lobes on its basal part; body unicolourous.

Minor (N = 4): HL: 0.59-0.6 (0.59); HW: 0.49-0.52 (0.51); SL: 0.58-0.66 (0.62); EL: 0.09-0.11 (0.1); WL: 0.7-0.73 (0.72); PSL: 0.08-0.1 (0.09); MTL: 0.47-0.52 (0.49); PNW: 0.34-0.35 (0.34); PTW: 0.08-0.1 (0.09); PPW: 0.14-0.15 (0.14); CI: 116.0-119.6 (117.1); SI: 115.0-133.4 (123.3); PSLI: 14.0-16.2 (15.4); PPI: 53.1-69.9 (63.1); PNI: 65.3-69.6 (67.6); MTI: 92.9-102.4 (97.9).

Head. Cephalic margin indistinctly convex or straight. Pilosity relatively sparse, long, decumbent to suberect. Sculpture foveolate; medial part of frons with smooth notch and indistinct, short rugulae; area posterolateral from eyes predominantly smooth. Clypeus with median longitudinal carina absent; two lateral longitudinal carinae absent. Scape, when laid back, surpassing the posterior head margin by one-fifth of its length; pilosity dense, subdecumbent to erect. Mesosoma. In lateral view, promesonotum moderately low and moderately long, arched; promesonotal groove absent; metanotal groove distinct; propodeal spines small and triangular. Pronotum with very indistinct and sparse foveolae; mesonotum, anepisternum, katepisternum, and propodeum smooth. Pilosity very sparse, moderately long, and erect. Postpetiole. Short, low, and relatively flat; with few short, erect setae. Gaster. With sparse, erect pilosity. Colour. Dark yellow, vertex and gaster slightly darker.

The following characters are found in most Pheidole sikorae species-group minors in Madagascar (Salata and Fisher 2020b). These characters also occur in , except for any differences noted in the paragraph above. Antennal sockets shallow; frontal lobes absent; occipital carina 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, with node moderately low, triangular, and small, with few short, erect setae; petiolar peduncle with ventral face slightly convex; postpetiole smooth, short, low, and slightly convex, with few short, erect setae; gaster smooth and shiny; body unicolourous.

Type material
Holotype. Madagascar. 1 major worker; Mahajanga; Region Sofia, Bemanevika; -14.337, 48.58874; alt. 1606 m; 14 Jan 2015; B. L. Fisher et al. leg.; montane rainforest, ex rotten log; BLF35640; CASENT0705586. Paratype. 1w.; same data as for holotype; CASENT0923289 (CASC).

Etymology
Latin for sparse in reference to sparse rugae on the frons.