Pheidole atsirakambiaty, Salata & Fisher, 2020

Salata, Sebastian & Fisher, Brian L., 2020, The ant genus Pheidole Westwood, 1839 (Hymenoptera: Formicidae) in Madagascar-taxonomic revision of the bessonii species-group, Zootaxa 4843 (1), pp. 1-64 : 15-17

Pheidole atsirakambiaty sp. nov.

Figs 10 A–F, 27B, 28B

HOLOTYPE: 1s., Madagascar, Fianarantsoa, Forêt d’Atsirakambiaty , 7.6 km 285° WNW Itremo, -20.59333 46.56333, 1550 m, 22-Jan-2003, montane rainforest, ex rotten log/termite mound, Fisher et al. leg. BLF07274, CASENT0491660 ( CASC) . PARATYPES: 6w., 2s., 1m., 1q., the same data as holotype, CASENT0491661, CASENT0491664, CASENT0491665, CASENT0491666, CASENT0872258, CASENT0491662 ( CASC, MHNG, PBZT) .

Other material. Madagascar. Fianarantsoa: 11w., 3s., Forêt d’Atsirakambiaty , 7.6 km 285° WNW Itremo, - 20.59333 46.56333, 1550 m, Fisher et al. leg. ( CASC) .

Geographic range. Madagascar, Fianarantsoa, Forêt d’Atsirakambiaty.

Diagnosis. Major workers. Head in full-face view sub-rectangular, not widening posteriorly, lateral margin relatively straight; sides of head with moderately dense, moderately long, suberect pilosity; frons with moderately thick and moderately dense costulae that arch posterolaterally; interspaces between costulae smooth to indistinctly rugopunctate; occipital lobes with thin and sparse rugulae that arch posterolaterally; interspaces between rugulae sparsely rugopunctate; scape, when laid back, exceeding the midlength of head by two-fifths of its length; inner hypostomal tooth absent; outer hypostomal tooth lobe-like, high, and wide, with top arching posterolaterally; median tooth present; promesonotum short, angular, and moderately low; posterior mesonotum moderately steep; mesonotal process tubercle-like; promesonotum with thick, dense and transverse rugae; interspaces between rugae distinctly punctate; katepisternum and propodeum with sparse rugae; interspaces between rugae rugopunctate; gaster shagreened; body black. Minor workers. Occiput slightly elongated; nuchal collar distinct; head mostly smooth; frons rugopunctate; scape, when laid back, exceeding posterior head margin by half its length; promesonotum low, long, and arched; promesonotal groove present; metanotal groove distinct; propodeal spines moderately small with wide base; mesosoma punctate; promesonotal dorsum with sparser puncta and transverse, thin rugae; body black.

Description. Major workers. Measurements (n=7): HL: 1.88–2.1 (1.99); HW: 1.75–1.97 (1.86); SL: 1.21– 1.25 (1.24); EL: 0.23–0.29 (0.26); WL: 1.62–1.74 (1.69); PSL: 0.23–0.32 (0.28); MTL: 1.36–1.49 (1.42); PNW: 0.59–0.74 (0.64); PTW: 0.19–0.31 (0.23); PPW: 0.52–0.73 (0.6); CI: 103.4–110.8 (107.0); SI: 61.5–71.5 (66.7); PSLI: 11.2–15.9 (14.0); PPI: 32.2–42.7 (39.3); PNI: 32.6–37.6 (34.5); MTI: 72.1–79.2 (76.1).

Head. In full-face view sub-rectangular, not widening posteriorly, lateral margin relatively straight ( Fig. 10B ). In lateral view sub-oval, not depressed posteriorly; ventral and dorsal margins convex; inner hypostomal tooth not visible. Side of the head with moderately dense, moderately long, suberect pilosity; head dorsum with relatively dense, long, decumbent to erect pilosity. Frons with moderately thick and moderately dense costulae that arch posterolaterally; interspaces between costulae smooth to indistinctly rugopunctate. Occipital lobe with thin and sparse rugulae that arch posterolaterally; interspaces between rugulae sparsely rugopunctate. Gena with dense and thick costulae; interspaces between costulae indistinctly rugopunctate. Sides posterolateral from eyes with dense but thin rugocostulae; interspaces between rugocostulae rugopunctate. Center of clypeus shiny and indistinctly punctate, lateral sides with distinct rugulae; median notch present, moderately wide and shallow; median and lateral longitudinal carinae present. Scape, when laid back, exceeding the midlength of head by two-fifths of its length; pilosity subdecumbent to erect ( Fig. 10B, D ). Inner hypostomal tooth absent; outer hypostomal tooth lobe-like, high and wide, with top arching posterolaterally; median tooth present ( Fig. 27B ). Mesosoma. In lateral view, promesonotum short, angular, and moderately low; posterior mesonotum moderately steep; mesonotal process distinct and tuberclelike; promesonotal groove absent; metanotal groove present; propodeal spines moderate with wide base and acute top; humeral tubercle weakly produced ( Fig. 10D ). Surface shiny; promesonotum with thick, dense, and transverse rugae; interspaces between rugae distinctly punctate; katepisternum and propodeum with sparse rugae; interspaces between rugae rugopunctate. Pilosity moderately dense, long, and erect ( Fig. 10D, F ). Petiole. In rear view node dorsoventrally convex ( Fig. 10D, F ). Gaster. Dull and shagreened; pilosity moderately sparse, long, and erect ( Fig. 10D, F ). Color. Black, antennae and legs brown, mandibles ochraceous ( Fig. 10D, F ).

Description. Minor workers. Measurements (n=10): HL: 0.85–0.95 (0.91); HW: 0.59–0.71 (0.65); SL: 1.13– 1.29 (1.23); EL: 0.16–0.2 (0.18); WL: 1.16–1.29 (1.23); PSL: 0.12–0.15 (0.13); MTL: 1.07–1.21 (1.13); PNW: 0.41–0.47 (0.44); PTW: 0.1–0.14 (0.12); PPW: 0.17–0.22 (0.2); CI: 133.4–143.6 (139.1); SI: 180.3–196.8 (189.1); PSLI: 13.0–16.5 (14.8); PPI: 47.7–68.3 (59.2); PNI: 64.1–72.1 (67.9); MTI: 163.4–183.0 (173.8).

Head. In full-face view oval, occiput slightly elongated; nuchal collar distinct ( Fig. 10A ). Pilosity relatively dense, moderately long, subdecumbent to erect. Sculpture shining and smooth; frons rugopunctate. Clypeus with median longitudinal carina present; two lateral longitudinal carinae absent. Scape, when laid back, exceeding posterior head margin by half its length; pilosity dense, subdecumbent to erect ( Fig. 10A, C ). Mesosoma. In lateral view, promesonotum low, long and arched; promesonotal groove present; metanotal groove distinct; propodeal spines moderately small, triangular and with wide base ( Fig. 10C ). Surface punctate; promesonotal dorsum with sparser puncta and thin, transverse rugae. Pilosity very sparse, long, and erect ( Fig. 10C, E ). Gaster. With sparse and erect pilosity ( Fig. 10C, E ). Color. Black, with legs, mandibles, and antennae brown ( Fig. 10C, E ).

Biology. The specimens were collected at 1550 m elevation, in montane rainforest and grassland. Nests were located in rotten logs on termite mounds and under stones.

Comments. Considering the ants known from northern Madagascar, Pheidole atsirakambiaty is most similar to P. voreios and parapatric P. bessonii . Its majors can be separated based on the black body and the presence of moderately thick, moderately dense costulae that arch posterolaterally, and rugulate frons and occipital lobes with smooth to indistinctly rugopunctate interspaces between rugulae. Majors of P. voreios and P. bessonii have a body that is brown to blackish brown, their head sculpture is never arches uniformly posterolaterally, and interspaces between rugocostulae are smooth to punctate. Minors can be distinguished based on their black body and distinctly punctate mesosoma. In contrast, minors of P. voreios and P. bessonii have a body that is bright brown to brown and their mesosoma is never distinctly punctate.

Etymology. From the type locality.

Figures

FIGURE 10. Pheidole atsirakambiaty, full-face view (A), profile (C), and dorsal view (E) of paratype minor worker (CASENT0491661) and full-face view (B), profile (D), and dorsal view (F) of holotype major worker (CASENT0491660).

FIGURE 27. Major worker, hypostomal tooth. Pheidole antsahabe (A). Pheidole atsirakambiaty (B). Pheidole bessonii (C). Pheidole clara (D). Pheidole decollata (E). Pheidole flammea (F). Pheidole flavodepressa (G). Pheidole grallatrix (H). Pheidole madecassa (I). Pheidole mantadioflava (J). Pheidole maro (K). Pheidole oswaldi (L). Pheidole ovalinoda (M). Pheidole similis (N). Pheidole tenebrovulgaris (O). Pheidole uranus (P). Pheidole voreios (Q). Pheidole zirafy (R).