Pheidole parvula

The species was collected between 750-1490 m in elevation, in montane forest and rainforest. Nests were located in rotten logs and litter.

Identification
Salata and Fisher (2020) - A member of the Pheidole sikorae species group. Minute species. Major: HL < 0.9 mm and WL < 0.8 mm; head in full-face view sub-oval, slightly widening posteriorly, with anterior and posterior sides convex, in lateral view sub-oval; ventral and dorsal faces convex; body dark orange; sides of head with moderately dense, moderately long, suberect pilosity; entire head distinctly sculptured, medial part of frons with thick and dense rugae and distinctly rugulate interspaces, rugae predominantly irregular and only centre and basal parts with few longitudinal rugulae; scape, when laid back, exceeding the midlength of head by one-fifth of its length; pronotum distinctly foveolate with additional irregular rugae on dorsum; anepisternum, katepisternum, and propodeum with fine rugulae and smooth interspaces; inner hypostomal teeth distinct, large, closely spaced, triangular, with rounded apex directed upward; outer hypostomal teeth lobe-like, slightly lower and wider than inner teeth; inner and outer hypostomal teeth moderately closely spaced and not connected by concavity; base of first gastral tergite smooth. Minor: HL < 0.5 mm and WL < 0.6 mm, scape, when laid back, surpassing the posterior head margin by one-fifth of its length; propodeal spines small and triangular; head relatively oval; body dark yellow; medial frons smooth; lateral sides of frons and vertex with fine, sparse, and irregular rugulae with smooth interspaces; area posterolateral from eyes smooth; mesosoma predominantly smooth with very sparse, fine, and irregular rugulae.

Pheidole parvula belongs to the group of species characterised by small body size (major workers: HL < 1.05 mm, WL < 0.9 mm and minor workers HL < 0.5 mm, WL < 0.6 mm), head sub-oval and slightly widening posteriorly with anterior and posterior sides convex in major workers, and minor workers with yellow to brown body colouration and head foveolate or predominantly smooth and relatively oval. The group includes six species: Pheidole havoana, Pheidole kely, P. parvula, Pheidole parvulogibba, Pheidole volontany, and Pheidole midongy. Within this group, P. parvula, described form two localities, Réserve Speciale d'Ambohitantely in Antananarivo and Ankerana in Toamasina, is most similar to parapatric P. kely P. parvula may also be confused with two taxa known only from the Anosyenne Mts. in Toliara, P. parvulogibba and P. havoana Minor workers of P. parvula distinctly differ from P. kely and P. havoana in never foveolate head; and from P. parvulogibba in lateral sides of frons and vertex with fine, sparse and irregular rugulae with smooth interspaces. Major workers of P. parvula differ from P. kely and P. parvulogibba by medial part of frons with thick and dense rugae and distinctly rugulate interspaces; and differ from P. havoana in promesonotum foveolate with sparse, thick to moderately thick, transverse to irregular rugae on dorsum and lack of smooth notches.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 * . Pheidole parvula Salata & Fisher, 2020: 127, figs. 49A–F, 64G, 66K (w.) MADAGASCAR.

Worker
Major (N = 2): HL: 0.86, 0.91; HW: 0.88, 0.9; SL: 0.49, 0.51; EL: 0.11, 0.12; WL: 0.79, 0.83; PSL: 0.15, 0.16; MTL: 0.48, 0.46; PNW: 0.43, 0.43; PTW: 0.09, 0.15; PPW: 0.28, 0.32; CI: 97.6, 101.7; SI: 56.1, 57.1; PSLI: 17.8, 17.8; PPI: 31.8, 45.3; PNI: 48.5, 48.2; MTI: 54.3, 51.7.

Head. In full-face view sub-oval, slightly widening posteriorly, with anterior and posterior sides convex. In lateral view sub-oval; ventral and dorsal faces convex; inner hypostomal teeth visible. Sides of the head with moderately dense, moderately long, suberect pilosity; whole head with dense, long, decumbent to erect pilosity. Medial part of frons with thick and dense rugae and distinctly rugulate interspaces, rugae predominantly irregular and only centre and basal parts with few longitudinal rugulae; lateral sides with thick, dense, and irregular rugae, interspaces shiny and distinctly rugulate. Occipital lobes with denser, irregular rugae and distinctly rugofoveolate interspaces. Area posterolateral from eyes with thick, dense, and irregular rugae, interspaces shiny and distinctly rugulate, posteriormost part distinctly foveolate with few thick, irregular rugae. Gena with relatively sparse, thick, and longitudinal rugae and indistinctly rugoreticulate interspaces. Centre of clypeus smooth and shiny, lateral sides with indistinct rugulae; median notch present, moderately wide, and shallow; median longitudinal carina present; lateral longitudinal carinae absent. Scape, when laid back, exceeding the midlength of head by one-fifth 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, slightly lower and wider than inner teeth; inner and outer hypostomal teeth moderately closely spaced and not connected by concavity. Mesosoma. In lateral view, promesonotum short, angular, and moderately low, posterior mesonotum moderately steep, mesonotal process very indistinct, tubercle-like, or absent; promesonotal groove absent; metanotal groove absent; propodeal spines long, with moderately narrow base and acute apex; humeral area laterally weakly produced. Surface shiny; pronotum distinctly foveolate with additional irregular rugae on dorsum; anepisternum, katepisternum, and propodeum with fine rugulae and smooth interspaces. Pilosity moderately dense, long, and erect. Petiole. Shiny with fine foveolae; node smooth to finely foveolate, triangular, with rounded and thick apex, in rear view node dorsoventrally straight to slightly convex; pilosity moderately sparse and erect. Postpetiole. Shiny and foveolate; dorsum with reduced sculpture; in dorsal view oval, lateral margins medially with two dentate projections; pilosity long, moderately sparse, and erect. Gaster. Shiny and smooth; pilosity dense, moderately long, and erect. Colour. Dark orange; mandibles and gaster brown.

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 = 3): HL: 0.45-0.49 (0.47); HW: 0.4-0.43 (0.42); SL: 0.43-0.45 (0.44); EL: 0.09-0.1 (0.09); WL: 0.55-0.59 (0.57); PSL: 0.05-0.05 (0.05); MTL: 0.34-0.36 (0.35); PNW: 0.27-0.29 (0.28); PTW: 0.06-0.07 (0.06); PPW: 0.09-0.1 (0.1); CI: 111.5-116.3 (113.5); SI: 103.0-108.5 (106.3); PSLI: 9.3-11.2 (10.1); PPI: 64.6-71.0 (67.3); PNI: 65.8-68.1 (66.9); MTI: 82.9-85.8 (84.3).

Head. Cephalic margin indistinctly concave to straight. Pilosity relatively dense, moderately long, decumbent to suberect. Sculpture shiny; medial frons smooth; lateral sides of frons and vertex with fine, sparse, and irregular rugulae with smooth interspaces; area posterolateral from eyes smooth; antennal sockets with few thick, curved outward rugae and indistinctly foveolate interspaces. 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 high and short, arched; promesonotal groove absent; metanotal groove distinct; propodeal spines small and triangular. Sculpture shiny and predominantly smooth with very sparse, fine, and irregular rugulae. Pilosity moderately sparse, moderately long, and erect. Gaster. With sparse, erect pilosity. Colour. Dark yellow, gaster and vertex brownish.

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; Toamasina; Ankerana; -18.40062, 48.81311; alt. 865 m; 17 Jan 2012; B. L. Fisher et al. leg.; rainforest, ex rotten log; BLF27754; CASENT0274865. Paratype. 1w.; same data as for holotype, CASENT0923270 (CASC).

Etymology
Latin for small in reference to the body size.