Pheidole pulchella Santschi, 1910

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 : 33-35

Pheidole pulchella Santschi

( Figures 51–56 )

Pheidole pulchella Santschi, 1910: 360 . Syntype workers: D.R. CONGO, Brazzaville, 1907 (A. Weiss) ( NHMB) [2 major workers and 4 minor workers examined]. [Misspelled as P. putchella by Emery, 1921: 89.]

Pheidole niapuana Wheeler 1922: 136 , fig. 34. Syntype workers: CONGO, Niapu, vi.1913 (H. O. Lang) (USNM) [7 major workers and 5 minor workers examined]. [Junior synonym of P. pulchella: Santschi, 1930: 59 ; confirmed here].

Pheidole pulchella var. achantella Santschi 1939: 242 . Holotype worker: D.R. CONGO, Brazzaville, 1907 (A. Weiss) (NHMB) [examined]. syn. n.

Diagnosis: Color orange (minor) to dark orange with lighter appendages (major). Minor workers: head shape rounded and relatively wide (CI: 82–90), occipital carina narrow. Scape and metafemur relatively long (SI: 147– 161, FI: 169–194), pilosity decumbent. Promesonotal outline in lateral view flat, without raised peak at humeri. Mesonotal processes relatively shallow, metanotal groove broad and deep in lateral view. Dorsopropodeum straight, propodeal spines relatively short (PSLI: 25–29). Standing hairs comparatively thick. Major workers: frontal carinae and antennal scrobes present, rugae in face of varying lengths, grading into weak oblique rugulae on posterolateral lobes, ground sculpture weakly to superficially punctate. Dorsal promesonotum transversely rugulose and weakly punctate, posteriorly towards mesonotum partly smooth and shiny. Mesonotal process strongly produced, right-angled. In lateral view dorsopropodeum anterior to propodeal spines longer than horizontal width of base of spines. Standing hairs relatively long and thick, absent from propodeum.

Description of minor worker: Measurements (n=15): HL: 0.856–0.944 (0.895), HW: 0.733–0.800 (0.766), SL: 1.133–1.254 (1.192), MDL: 0.578–0.644 (0.610), EL: 0.167–0.189 (0.173), MFL: 1.317–1.508 (1.414), MTL: 1.056–1.133 (1.092), WL: 1.156–1.317 (1.258), PSL: 0.222–0.267 (0.244), PTH: 0.172–0.211 (0.190), PPH: 0.206–0.244 (0.221), PTL: 0.289–0.389 (0.347), PPL: 0.211–0.256 (0.237), PTW: 0111–0.133 (0.122), PPW: 0.222–0.267 (0.235), PW: 0.478–0.544 (0.506); CI: 82–90 (86), SI:147–161 (156), MDI: 75–83 (80), PSLI: 25–29 (27), PWI: 64–68 (66), FI: 169–194 (185), PpWI: 182–218 (193), PpLI: 117–175 (147).

Head longer than wide (CI: 82–90), with sides posterior of eye-level evenly rounded towards posterior margin. Occipital carina conspicuous, medially and laterally faintly impressed. Mandibles of moderate length (MDI: 75– 83), dorsally smooth to superficially rugulose. Clypeus smooth, median and submedian carinae absent, lateral carinae conspicuous, sometimes short. Frons and vertex smooth, hexagonally micropunctate, with superficial punctures on malar area and near eyes. Malar carinae weak and interrupted, disappearing at posterior eye-level. Scape relatively long (SI: 147–161) in full-face view and when laid back surpassing posterior margin by more than one third of its length with decumbent pilosity. Promesonotal outline in lateral view flat, obtusely angulate at posterior declivity. First and second mesonotal process weakly produced, at edges slightly rounded, not marginate dorsally. Humeri with small, weakly marginate angle, not peaked in lateral view. Pronotal and mesonotal declivities shallow and flatly declining towards deeply and broadly impressed metanotal groove. Promesonotum anteriorly on neck weakly punctate, with short to moderately long, irregular rugulae, remainder smooth and shiny to superficially punctate. Mesonotum dorsally smooth to superficially punctate. Mesopleuron and propodeum weakly punctate, with superficially sculptured or almost smooth spots on anepisternum, katepisternum, and posterior dorsopropodeum. Spines relatively short (PSLI: 25–29), in dorsal view, at apices almost parallel. Metafemur relatively long (FI: 169–194), metatibia pilosity decumbent. Petiolar node and postpetiole weakly punctate lateroventrally and ventrally, dorsum with superficially punctate to smooth and shiny area, peduncle also weakly to superficially punctate dorsally, without smooth strip medially. First gastral tergite smooth and shiny, except very narrow, superficially punctate anterior strip. Standing hairs relatively stiff and of varying lengths, longest hairs on pronotum, gaster and head. Mesonotum and propodeum with shorter subdecumbent hairs, also present on head and projecting beyond lateral margin anterior and posterior of eye-level. Color yellow to light orange.

Description of major worker: Measurements (n=13): HL: 1.940–2.225 (2.140), HW: 2.000–2.275 (2.162), SL: 1.056–1.167 (1.134), MDL: 0.900–1.111 (1.016), EL: 0.233–0.256 (0.243), MFL: 1.667–1.840 (1.738), MTL: 1.286–1.429 (1.353), WL: 1.397–1.740 (1.651), PSL: 0.244–0.378 (0.316), PTH: 0.333–0.389 (0.357), PPH: 0.367–0.500 (0.443), PTL: 0.533–0.644 (0.594), PPL: 0.333–0.411 (0.378), PTW: 0.200–0.267 (0.240), PPW: 0.422–0.611 (0.524), PW: 0.811–1.033 (0.950); CI: 98–103 (101), SI: 51–56 (53), MDI: 43–50 (47), PSLI: 11–17 (15), PWI: 39–47 (44), FI: 76–90 (80), PeI: 22–29 (25), PpI: 47–61 (55), PpWI: 200–239 (218), PpLI: 141–167 (157).

Head about as long as wide (CI: 98–103), frontal carinae and antennal scrobes conspicuous. Frons longitudinally rugose, with irregular pattern of moderately long to shorter rugae, spaces between rugae weakly punctate to almost smooth. Rugae grading weaker posteriorly and curving towards posterolateral lobes, or replaced by oblique, weak, rugulose-punctate sculpture. Scape pilosity appressed. Promesonotal outline in lateral view rounded or very weakly subangulate, dorsally and anterolaterally with transverse and irregular rugulose and weakly punctate sculpture. Posterolaterally with smooth area, posterodorsally towards well-produced, right-angled mesonotal process weakly sculptured and partly smooth, at its edges weakly marginate, steeply declining towards small or inconspicuous second mesonotal process, terminating in narrow and short transverse ridge. Metanotal groove in lateral view narrow and shallow, dorsopropodeum weakly to superficially punctate. In profile, dorsopropodeum anterior to propodeal spines subequal to horizontal width of base of spine. Propodeal spines weakly curved posteriorly, posteropropodeum with weak transverse rugulae overlaying punctures. Punctures on mesopleuron and metapleuron weak and dense, posterobasally around long and conspicuous metapleural carina and gland scrobe superficial to smooth and shiny. Metatibia with short appressed pilosity. Petiole and postpetiole very densely punctate, anterodorsal petiole superficially sculptured, posterodorsal postpetiole with short irregular rugulae. Anterior half of first gastral tergite shagreened, posterior half smooth and hexagonally microsculptured. Long standing hairs acute, relatively slender, abundantly present on dorsal head, promesonotum, waist segments, and gaster, with additional short appressed pubescence. Color orange to darker orange, legs lighter.

Discussion: Type specimens of the three synonyms Pheidole pulchella , P. pulchella achantella and P. niapuana are conspecific. All of them were collected from only two different localities in Congo and in the D.R. Congo. As they share the same morphometric and diagnostic characters, measurement values for the junior synonym specimens were combined with those for the P. pulchella types and the new material from Gabon. The latter was collected in rainforest habitat from sifted leaf-litter. Minor workers of P. pulchella can be differentiated easily from those of P. christinae and P. heliosa by the relatively wider, more circular, head (CI: 82–90 [ P. pulchella ] versus CI: 79–84 [ P. christinae ] and CI: 73–76 [ P. heliosa ]), less abundant and thicker standing hairs, short, decumbent scape and metatibia pilosity versus suberect to erect hairs, and shorter propodeal spines (PSLI: 25–29 versus PSLI: 26–36 and PSLI: 28–37). Major workers of P. pulchella are separated from those of P. heliosa by presence of frontal carinae and antennal scrobes. They have a less coarsely sculptured face and promesonotum, a mesonotal processes which is separated from the pronotum by an obtuse angle, and curved versus straight propodeal spines. Majors from the P. niapuana types and the newer material from Gabon differ slightly in coloration from the P. pulchella and P. pulchella achantella type material. The latter are somewhat darker which might be a result of age or former storage conditions. Most of the material from Gabon was collected from pitfall traps and sifted leaf-litter within rainforests.

Additional material examined: GABON: (1 major worker, 2 minor workers) La Makande, Foret des Abeilles, i–ii.1999 (S. Lewis); (2 major workers, 2 minor workers) Prov. Ogooue Maritime, Reserve Monts Doudou, 24.3 km 103° NW Doussala, 02° 13.4' S, 10° 24.4' E, 6–11.iii. 2000, 375 m (B.L. Fisher); (3 minor workers) Prov. Woleu-Ntem, 31.3 km 108° ESE Minvoul, 02° 04.8' N, 12° 24.4' E, 600 m, 12.ii.1998 (B.L. Fisher); (1 major worker, 1 minor worker) Prov. Woleu-Ntem, 31.3 km 108° ESE Minvoul, 02° 04.8' N, 12° 24.4' E, 600 m, 11.ii.1998 (B.L. Fisher).

Figures

FIGURE 51 – 56: P. pulchella Santschi: full-face, lateral & dorsal view of minor (Fig. 51 – 53) (Gabon, CASENT 0227963) and major worker (Fig. 54 – 56) (Gabon, CASENT 0218336).