Pheidole nimba Bernard, 1953

FISCHER, GEORG., GARCIA, FRANCISCO HITA & PETERS, MARCELL K., 2012, Taxonomy of the ant genus Pheidole Westwood (Hymenoptera: Formicidae) in the Afrotropical zoogeographic region: definition of species groups and systematic revision of the Pheidole pulchella group, Zootaxa 3232 (1), pp. 1-43 : 31-32

Pheidole nimba Bernard

( Figures 48–50 )

Pheidole nimba Bernard, 1953: 224 , fig. 8. Syntypes (2 minor workers): GUINEA, Nion , 1300 m, maqun crête lamothe (F. Bernard) “No. 228 types ” ( MNHN) [examined].

Diagnosis: Pheidole nimba is the species with the most extensive and strongest sculpture in this group. Color is dark brown. Minor worker: head shape rounded (CI: 90), with medially impressed occipital carina. Uniformly and coarsely punctate on all dorsal surfaces from clypeus to anterior half of first gastral tergite, except smooth triangular spot between frontal carinae, and spaces between cross-ribs of metanotal groove. Standing hairs present on head, meso- and metasoma, moderately long and stiff. Scape and metatibia pilosity decumbent.

Description of minor worker: Measurements (syntype): HL: 0.856, HW: 0.767, SL: 0.989, MDL: 0.578, EL: 0.189, MFL: 1.133, MTL: 0.889, WL: 1.156, PSL: 0.233, PTH: 0.178, PPH: 0.211, PTL: 0.356, PPL: 0.233, PTW: 0.122, PPW: 0.222, PW: 0.517; CI: 90, SI: 129, MDI: 75, PSLI: 27, PWI: 67, FI: 148, PpWI: 182, PpLI: 152.

Head longer than wide (CI: 84–90), almost elliptical, with posterior margin weakly compressed. Face strongly punctate, median part of clypeus weakly punctate, median carina conspicuous and short, lateral carinae well-developed. Punctures on malar area overlain by weak to irregular rugulae, ending at eye-level. Occipital carina narrow, medially conspicuously impressed, scapes relatively short (SI: 129), with decumbent pilosity. Promesonotal outline weakly convex in lateral view, subangulate towards posterior declivity. Mesonotal process flatly produced, angulate, declivity long and straight. Second mesonotal process more shallowly produced, similar in shape to first process, metanotal groove conspicuous and deep. Dorsopropodeum in lateral view distinctly declining towards propodeal declivity. Mesosoma strongly punctate except small superficially sculptured spot on posterior lateropronotum, punctures on anteropronotum overlain with weak and irregular transverse rugulae. Propodeal spines and metafemur moderately short (PSLI: 27, FI: 148), metatibia with decumbent pilosity. Petiole and postpetiole densely punctate dorsally, except anterodorsal surface of petiole ventrally punctate. Anterior half of first gastral tergite punctate, posterior half shagreened. Standing hairs moderately long and stiff, partly with blunt to truncate apices and relatively scarce on head and on pronotum. Pilosity on mesonotum and propodeum subdecumbent and shorter, additional short decumbent to subdecumbent pubescence present. Color uniformly brown.

Discussion: In habitus and amount of punctate sculpture Pheidole dea is the species that most closely resembles P. n i m b a. However, the clypeus, central area on frons, and posterior dorsopropodeum are smooth to superficially punctate, and standing hairs are relatively rare to almost absent in P. d e a. Pheidole nimba was found in the Mount Nimba Nature Reserve in Guinea, close to the border of Ivory Coast, on the Nion crest and at an altitude of 1300 m. It was described on the basis of four minor workers, two of which were examined for this redescription (one was without head, and thus was not measured). Major workers remain unknown, but one specimen from Ghana, which did not match with any of the other species presented here, might be conspecific with P. n i m b a, although the differences in sculpture to the type specimens are relatively strong. Until additional material from the different localities becomes available the description of major workers will not be possible.

Figures

FIGURE 48 – 50 P. nimba Bernard: full-face, lateral & dorsal view of minor worker (Guinea, CASENT 0227967).