The Ants of Africa
Genus Pheidole
Pheidole semidea Fischer, Hita Garcia & Peters

Pheidole semidea Fischer, Peters & Hita Garcia

return to key {link to the Hymenoptera Name Server} Type location Nigeria (Fischer, Hita Garcia & Peters, 2012, 38, Figs. 63-68), Gambari, 22.vii.69, in log (B. Bolton) (BMNH: CASENT0227959). Paratypes: (2 major workers, 5 minor workers) same data as holotype (BMNH: CASENT0227960, CASENT0227961).
major and minor described .

Diagnosis: Color light to dark brown.
Major: Frons with moderately long rugae, vertex weakly rugose-reticulate, and posterolateral lobes with oblique rugulae. Mesonotal process in lateral view almost right-angled, second process very shallow and raised above level of dorsopropodeum. In profile, dorsopropodeum anterior to propodeal spines longer than horizontal width of base of spine. Postpetiole moderately wide (PWI 192–221) and standing hairs on pronotum medially inclined.
Minor: Head shape rounded (CI 85–89), with medially impressed occipital carina. Dorsal surfaces of head, promesonotum and metasoma smooth, at most superficially punctate. Second mesonotal process in lateral view distinctly raised above level of anterior dorsopropodeum. Petiole relatively short (PpLI: 126–144).

Description of major worker:  Face entirely rugose-punctate, rugae relatively long and sometimes interrupted on frons, posteriorly with some weak cross-meshes, disappearing towards obliquely and weakly rugulose-punctate posterolateral lobes. Outer corners of posterolateral lobes and spaces between rugae on frons superficially punctate, laterally of antennal scrobe irregularly rugose-reticulate. Scape with decumbent pilosity. Promesonotum in lateral view short, posteriorly sub-angulate, declivity short, anterodorsally and anterolaterally weakly and irregularly rugulose-punctate, grading to superficially punctate posteriorly on dorsopronotum, lateropronotum and mesonotum. First mesonotal process right-angled, with a steep declivity. Second process small or reduced to short, narrowly raised carina, but raised above level of dorsopropodeum. Meso- and metapleuron punctate, with smooth area on katepisternum and posteroventral metapleuron. Metapleural carina relatively short and weak, gland scrobe weak to inconspicuous. Dorsal and posterior propodeum smooth to superficially punctate, with transverse rugula(e) between spines and moderately developed, longitudinal rugula(e) posteriorly along spines. Petiole and postpetiole punctate, except medial area of anterodorsal petiole. First gastral tergite shagreened, posteriorly slightly weaker. Metatibia with appressed pilosity. Acute, long standing hairs present on head, postpetiole, dorsal gaster and pronotum, on the latter medially inclined. Color reddish brown, gaster darker.
Measurements (holotype): HL 1.800, HW 1.760, SL 0.978, MDL 0.833, EL 0.222, MFL 1.444, MTL 1.078, WL 1.429, PSL 0.300, PTH 0.333, PPH 0.367, PTL 0.500, PPL 0.311, PTW 0.222, PPW 0.467, PW 0.800
Indices: CI 98, SI 56, MDI 47, PSLI 17, PWI 45, FI 82, PeI 28, PpI 58, PpWI 210, PpLI 161.
Measurements (n=3): HL 1.619–1.860 (1.705), HW 1.635–1.820 (1.724), SL 0.922–1.000 (0.975), MDL 0.722–0.833 (0.792), EL 0.211–0.222 (0.215), MFL 1.349–1.444 (1.393), MTL 1.000–1.111 (1.061), WL 1.286–1.476 (1.365), PSL 0.244–0.306 (0.285), PTH 0.250–0.311 (0.285), PPH 0.311–0.406 (0.357), PTL 0.489–0.556 (0.515), PPL 0.333–0.344 (0.336), PTW 0.200–0.233 (0.211), PPW 0.383–0.500 (0.447), PW 0.711–0.800 (0.764)
Indices: CI 98–106 (101), SI 55–58 (57), MDI 43–48 (46), PSLI 15–18 (16), PWI 39–47 (44), FI 79–83 (81), PeI 25–30 (28), PpI 50–66 (579, PpWI 192–221 (212), PpLI 147–161(153).

Description of minor worker:  Head shape in full-face view slightly elliptical with roundly convex posterior margin (CI 85–89). Occipital carina conspicuous and medially impressed. Clypeus smooth, lateral carinae weak. Face smooth, except hexagonal microsculpture, superficially punctate laterally towards eyes. Malar rugulae well-developed, disappearing posterior of eyes. Scape surpassing posterior margin by about one third of its length (SI 134–150), with decumbent pilosity, apically some hairs subdecumbent. Promesonotum in lateral view flat, subangular, anterodorsally towards neck weakly punctate, rest smooth. First mesonotal process obtusely angulate, dorsally smooth. Second process conspicuous and distinctly raised above level of dorsopropodeum. Metanotal groove asymmetrically impressed, posteriorly more shallowly. Mesopleuron and propodeum punctate, with superficially sculptured spots on katepisternum and posterior dorsopropodeum. Spines moderately long (PSLI 26–35), posteriorly strongly curved. Metafemur long (FI 158–173), metatibial pilosity decumbent. Petiole punctate laterally and ventrally, dorsolateral postpetiole and ventral process weakly punctate, dorsum of both waist segments smooth, partly micropunctate. Gaster smooth, anteriorly near insertion of postpetiole superficially punctate. Standing hairs on head, postpetiole and gaster long and acute, on petiole short and on promesonotum mostly moderately long and subdecumbent, directed towards center or dorsopronotum. Body surface also with several short and relatively long appressed hairs. Color light to dark brown, gaster darker, mandibles partly transparent.
Measurements (n=5): HL 0.778–.0811 (0.796), HW 0.689–0.722 (0.697), SL 0.967–1.033 (0.989), MDL 0.533–0.544 (0.542), EL 0.156–0.189 (0.169), MFL 1.111–1.190 (1.149), MTL 0.900–0.911 (0.904), WL 1.044–1.111 (1.084), PSL 0.206–0.233 (0.222), PTH 0.167–0.172 (0.168), PPH 0.178–0.200 (0.192), PTL 0.256–0.289 (0.276), PPL 0.189–0.222 (0.207), PTW 0.111–0.122 (0.114), PPW 0.200–0.222 (0.211), PW 0.467–0.478 (0.475)
Indices: CI 85–89 (88), SI 134–150 (142), MDI 75–79 (78), PSLI 26–29 (28), PWI 68–69 (69), FI 160–173 (165), PpWI 173–200 (185), PpLI 126–144 (134).

Discussion: Pheidole semidea, in morphometrics and overall habitus, is closest to P. dea, but differentiated from the latter by the following characters: sculpture of minor workers in face strongly reduced to mostly smooth and shiny versus weakly to superficially punctate in P. dea, second mesonotal process higher situated and raised above dorsopropodeal outline, spines more strongly curved, petiole shorter and postpetiole longer (PpLI 126–144 versus PpLI 156–223). Rugae on frons and vertex of major workers moderately long, posterolateral lobes with oblique rugulae versus very long, longitudinal and subparallel rugae from frons to head margin in P. dea, postpetiole on average wider (PpWI 192–221) in P. semidea versus relatively narrow (PpWI 177–210) in P. dea, and first gastral tergite almost completely shagreened versus only anteriorly shagreened in P. dea. Given the relatively minor differences between minor workers of the two species, it is possible that they are conspecifics and that intermediate forms exist within or between the West and East African populations. Yet, we propose that P. semidea and P. dea should be considered separate species until additional data from future sampling proves otherwise. The P. semidea types were collected from a log at Gambari, Nigeria, and another major was collected from Ibadan, Nigeria.
Additional material examined: NIGERIA: (1 major worker) Ibadan, IITA (= International Institute of Tropical Agriculture), 18.v.81, no. 16 (A. Russel-Smith).

{Pheidole semidea} Nigeria specimens (Pheidole species D in Taylor, 1980a: 19).

Major - TL 5.6 mm, HL 1.80, HW 1.80, SL 1.18, PW 0.84
Minor - TL 3.39 mm, HL 0.86, HW 0.73, SL 0.98, PW 0.50
Colour very dark red-brown to black.
Major markedly rugose all over the dorsum of the head. Alitrunk faintly reticulorugose; the pedicel and gaster finely punctate. Propodeal spines long, slender, acute and slightly curved.
Minor almost unsculptured and shiny, with a faint reticulation on the propodeum and pedicel. Erect hairs coarse and relatively sparse. Propodeal spines long, slender and acute.

Collected from dead wood on the ground and from the base of a cocoa tree at the Cocoa Research Institute of Nigeria, Idi Ayunre.

Found in Ghana cocoa at Kade by Majer (1975, 1976b), using pkd, with two workers in a single sample (not listed by Fischer, Hita Garcia & Peters, 2012)

{Pheidole semidea} The photomontage is from Fischer, Hita Garcia & Peters (2012). The minor is exactly as I drew it.

2007, 2008, 2009, 2010, 2011, 2012, 2014 - Brian Taylor CBiol FSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.