Pheidole mikros, Salata & Fisher, 2020

Salata, Sebastian & Fisher, Brian L., 2020, Taxonomic revision of the Pheidole sikorae species group (Hymenoptera, Formicidae) from Madagascar, ZooKeys 949, pp. 1-185 : 1

publication ID

https://dx.doi.org/10.3897/zookeys.949.51269

publication LSID

lsid:zoobank.org:pub:93BFA448-BB73-43CD-BC4E-A86090DA63D5

persistent identifier

https://treatment.plazi.org/id/6378BC54-2DA8-44F8-9768-7210E473D2CF

taxon LSID

lsid:zoobank.org:act:6378BC54-2DA8-44F8-9768-7210E473D2CF

treatment provided by

ZooKeys by Pensoft

scientific name

Pheidole mikros
status

sp. nov.

Pheidole mikros sp. nov. Figs 46A-F View Figure 46 , 64D View Figure 64 , 66H View Figure 66

Type material.

Holotype. Madagascar. • 1 major worker; Antsiranana; Sakaramy; -12.44131, 49.22723; alt. 365 m; 13 May 2011; B. L. Fisher et al. leg.; tropical dry forest, under tree bark, live tree; BLF27321; CASENT0923271 (CASC). Paratype. • 1w.; same data as for holotype, CASENT0261101 (CASC).

Other material.

Madagascar. - Antsiranana: •1w.; Parc National de Marojejy, Manantenina River, 28.0 km 38°NE Andapa, 8.2 km 333°NNW Manantenina; -14.43667, 49.775; alt. 450 m; 23 Nov 2004; B. L. Fisher et al. leg.; rainforest, ex rotten log; BLF10982 (CASC). •1w., 1s.; Réserve Spéciale de l’Ankarana, 22.9 km 224°SW Anivorano Nord; -12.90889, 49.10983; alt. 80 m; 10 Feb 2001; B. L. Fisher et al. leg.; tropical dry forest, ex rotten log; BLF03008 (CASC).

Diagnosis.

Minute species. Major workers. HL <0.9 mm and WL <0.75 mm; head in full-face view elongate, not widening posteriorly with posterior sides slightly convex, in lateral view sub-oval and short with convex dorsal and ventral sides; body brownish orange; sides of head with moderately sparse, moderately long, subdecumbent to suberect pilosity; entire head distinctly sculptured, medial part of frons with thick and longitudinal rugae and indistinctly rugulate and never smooth interspaces, occipital lobes with dense and irregular rugae with distinctly rugoreticulate interspaces; scape, when laid back, slightly exceeding the midlength of head; lateral sides of promesonotum distinctly foveolate with additional sparse and indistinct rugulae; inner hypostomal teeth large, closely spaced, triangular, with rounded apex directed upward; outer hypostomal teeth lobe-like, slightly lower and narrower than inner teeth; inner and outer hypostomal teeth moderately closely spaced and not connected by concavity; base of first gastral tergite shagreened. Minor workers. 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, triangular; head relatively rectangular; body yellowish brown; lateral sides of frons with fine, sparse, and irregular rugulae with smooth interspaces; vertex with distinct, sparse, and transverse rugulae; mesosoma with sparse and moderately thick network of irregular rugulae; mesonotum and katepisternum smooth.

Description.

Major workers. Measurements (N = 2): HL: 0.86, 0.88; HW: 0.8, 0.83; SL: 0.49, 0.47; EL: 0.12, 0.11; WL: 0.74, 0.77; PSL: 0.12, 0.13; MTL: 0.44, 0.41; PNW: 0.46, 0.46; PTW: 0.13, 0.14; PPW: 0.35, 0.37; CI: 107.6, 105.2; SI: 61.7, 56.5; PSLI: 13.9, 15.0; PPI: 37.8, 38.7; PNI: 57.3, 55.6; MTI: 54.8, 49.7.

Head. In full-face view elongate, not widening posteriorly, with anterior and posterior sides slightly convex (Fig. 46B View Figure 46 ). In lateral view sub-oval; ventral and dorsal faces convex; inner hypostomal teeth visible. Sides of the head with moderately sparse, moderately long, subdecumbent to suberect pilosity; whole head with dense, long, decumbent to erect pilosity. Medial part of frons with thick, longitudinal, and dense rugae and indistinctly rugulate interspaces, rugae more irregular and directed slightly outward on posteromedial part; lateral sides with thick, sparse, and predominantly longitudinal rugae, interspaces shiny and distinctly foveolate. Occipital lobes with denser, irregular rugae and distinctly foveolate interspaces. Area posterolateral from eyes foveolate with sparse and moderately thick rugae. Gena with relatively sparse, thick, and longitudinal rugae and indistinctly foveolate 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, slightly exceeding the midlength of head; pilosity subdecumbent to erect (Fig. 46B, D View Figure 46 ). Inner hypostomal teeth distinct, large, closely spaced, triangular, with rounded apex directed upward; outer hypostomal teeth lobe-like, slightly lower and narrower than inner teeth; inner and outer hypostomal teeth moderately closely spaced and not connected by concavity (Fig. 64D View Figure 64 ). Mesosoma. In lateral view, promesonotum short, angular, and moderately low, posterior mesonotum moderately steep, mesonotal process very indistinct, tubercle-like; promesonotal groove absent; metanotal groove absent; propodeal spines moderately long, with wide base and acute apex; humeral area laterally weakly produced (Fig. 46D View Figure 46 ). Surface shiny and distinctly foveolate with additional sparse and indistinct rugulae on promesonotum. Pilosity moderately sparse, moderately long, and erect (Fig. 46D, F View Figure 46 ). Petiole. Shiny with dense foveolae; node smooth to finely foveolate, triangular, with rounded and thick apex, in rear view node dorsoventrally concave; pilosity moderately sparse and erect (Fig. 46D, F View Figure 46 ). Postpetiole. Shiny and foveolate; dorsum with slightly reduced sculpture; in dorsal view trapezoid, lateral margins medially with two large dentate lobes; pilosity long, moderately sparse, and erect (Fig. 46D, F View Figure 46 ). Gaster. Shiny, its base shagreened; pilosity dense, moderately short, and erect (Fig. 46D, F View Figure 46 ). Colour. Brownish orange; mandibles and gaster brown (Fig. 46D, F View Figure 46 ).

Minor workers. Measurements (N = 3): HL: 0.47-0.48 (0.47); HW: 0.4-0.42 (0.41); SL: 0.42-0.43 (0.43); EL: 0.08-0.08 (0.08); WL: 0.54-0.56 (0.55); PSL: 0.07-0.07 (0.07); MTL: 0.3-0.31 (0.31); PNW: 0.29-0.3 (0.29); PTW: 0.07-0.07 (0.07); PPW: 0.12-0.13 (0.12); CI: 110.8-117.7 (115.1); SI: 101.9-105.4 (104.2); PSLI: 14.4-15.5 (15.0); PPI: 54.7-57.5 (56.4); PNI: 67.7-73.7 (71.6); MTI: 73.4-76.0 (74.4).

Head. Cephalic margin indistinctly concave to straight (Fig. 46A View Figure 46 ). Pilosity relatively dense, moderately long, decumbent to suberect. Sculpture shiny; medial frons smooth; lateral sides of frons with fine, sparse, and irregular rugulae with smooth interspaces; vertex with distinct, sparse, and transverse rugulae; area posterolateral from eyes with fine, sparse, and irregular rugulae with smooth interspaces; 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 (Fig. 46A, C View Figure 46 ). Mesosoma. In lateral view, promesonotum moderately high and short, arched; promesonotal groove absent; metanotal groove distinct; propodeal spines small and triangular (Fig. 46C View Figure 46 ). Sculpture shiny with sparse and moderately thick network of irregular rugulae; mesonotum and katepisternum smooth. Pilosity moderately sparse, moderately long, and erect (Fig. 46C, E View Figure 46 ). Gaster. With sparse, erect pilosity (Fig. 46C, E View Figure 46 ). Colour. Yellowish brown, legs and antenna yellow (Fig. 46C, E View Figure 46 ).

Etymology.

Greek for small in reference to the body size.

Biology.

The species was collected between 80-450 m in elevation, in rainforest and tropical dry forest. Nests were located in rotten logs and under tree bark.

Comments.

Pheidole mikros sp. nov. 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 elongate and not widening posteriorly in major workers, and minor workers with head predominantly smooth and relatively rectangular, and body colouration yellow to brown. The group includes four species: P. flavominuta sp. nov., P. nitidobruna sp. nov., P. mikros sp. nov., and P. beanka sp. nov. Pheidole mikros sp. nov. is known from the area between Andapa and Antisiranana and is parapatric with Pheidole nitidobruna sp. nov. described from Makirovana forest in Antsiranana. Major workers of P. mikros sp. nov. can be separated from P. nitidobruna sp. nov. by predominantly indistinctly rugulate interspaces on frons, occipital lobes with distinctly foveolate or rugoreticulae interspaces, and absence of smooth notches on lateral sides of promesonotum. Minor workers of P. mikros sp. nov. can be separated from P. nitidobruna sp. nov. based on presence of sculpture on vertex and frons and presence of small, triangular propodeal spines. However, the morphology of P. mikros sp. nov. is most similar to P. beanka sp. nov., which is known from Réserve forestière Beanka in Mahajanga. Pheidole mikros sp. nov. differs from P. beanka sp. nov. by the combination of the following characters: major workers have medial part of frons with indistinctly rugulate interspaces and their propodeal spines are moderately long; minor workers have lateral sides of frons with fine, sparse, and irregular rugulae, mesosoma covered by a sparse and moderately thick network of irregular rugulae, and body is yellowish brown.

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Hymenoptera

Family

Formicidae

Genus

Pheidole