Pheidole darwini Fischer, Hita Garcia &
Type location Gabon
(Fischer, Hita Garcia & Peters, 2012: 19, Figures 21-26); Prov.
km 108° ESE Minvoul, 02° 04.8' N, 12° 24.4' E, 600 m, 7.ii.1998 (B.L.
Fisher) (CASC: CASENT0218307).
Major & minor only described .
Paratypes: (8 major workers) same data
as holotype (BMNH: CASENT0218300; CASC: CASENT0218303,
MHNG: CASENT0218301, SAMC: CASENT0218302); (12 minor workers) 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) (BMNH: CASENT0218313, CASENT0218315, CASC:
CASENT0218311, CASENT0218317, CASENT0218318, MHNG: CASENT0218316, SAMC:
CASENT0218319); (18 minor workers) Prov. Woleu-Ntem, 31.3 km 108° ESE
Min- voul, 02° 04.8' N, 12° 24.4' E, 600 m, 12.ii.1998 (B.L. Fisher)
(CASC: CASENT0218324, CASENT0218325, CASENT0218326, CASENT0218327,
medium to dark brown, appendages slightly lighter.
Major worker: head
sculpture weakly rugose-punctate, with moderately long rugae.
Posterolateral lobes smooth and shiny, scape with appressed to
decumbent pilosity plus a few erect hairs along outer edge.
Dorsopropodeal sculpture weakly and irregularly transversely
In profile, dorsopropodeum anterior to propodeal spines shorter than
or subequal to horizontal width of base of spine. Standing hairs long
and thick, present everywhere except propodeum. Metatibia pilosity
appressed to decumbent with additional subdecumbent to suberect hairs
along outer edge.
Minor worker: head shape elliptical (CI: 84–89),
posterior of eye-level with laterally projecting hairs. Posterior head
narrow, vertex smooth. Scapes moderately long (SI: 139–160) with
suberect pilosity. Dorsopronotum punctate anteriorly, partly overlain
with irregular rugulae, posteriorly smooth. Spines relatively long
(PSLI: 29–35), metatibia pilosity subdecumbent.
Frons and sides of head weakly to superficially
rugose-punctate, grading weaker on anterior posterolateral lobes,
posteriorly smooth and
shiny, median excavation with a narrow superficially sculptured strip.
Laterally and in profile view smooth area extending anteriorly, almost
towards eye-level. Pilosity on scape basally appressed, apically
decumbent, in addition with three to five erect hairs, distributed
along outer edge. Promesonotal outline slightly rounded, mesonotal
process subangulate, with relatively steep posterior declivity. Second
process inconspicuous, weakly raised carina or narrow ridge present
instead. Pronotum transversely to irregularly rugulose-punctate,
posterodorsally less rugulose, punctures either slightly weaker or
superficial, posterolaterally smooth and shiny or superficially
punctate-rugose. Humeral area slightly processed to subangulate
laterally, promesonotal declivity smooth, with hexagonal
microsculpture. Meso- and metapleuron punctate, dorsopropodeum weakly
punctate. In profile, dorsopropodeum anterior to propodeal spines
shorter than horizontal width of base of spine. Area between spines and
posteropropodeum punctate or weakly punctate, overlain by weak or
superficial transverse rugulae, also posterolateral rugae towards
metapleural carinae present. Petiole and postpetiole densely punctate,
except smooth anterodorsal petiole. Postpetiolar ventral process
significantly anteriorly produced. Punctures on anterior half of first
gastral tergite grading to hexagonal microsculpture on second half.
Long standing, often truncated, hairs relatively abundant on dorsal
body, but absent from propodeum. Metatibia with appressed to decumbent
pilosity and with subdecumbent to suberect hairs along outer edge.
Color brown to dark brown, appendages lighter.
Measurements (holotype): HL 1.960, HW
1.960, SL 1.044, MDL 1.000, EL 0.239, MFL 1.571, MTL 1.190, WL
1.476, PSL 0.356, PTH 0.322, PPH 0.400, PTL 0.556, PPL 0.356, PTW
0.222, PPW 0.500, PW 0.878.
Indices: CI 100, SI 53, MDI 51, PSLI 18, PWI
45, FI 80, PeI 25, PpI 57, PpWI 225, PpLI 156.
Measurements (n=9): HL 1.980–2.200 (2.099), HW 1.960–2.225 (2.120),
SL 1.011–1.133 (1.056), MDL 0.944–1.056 (1.011), EL 0.239–0.267
(0.251), MFL 1.556–1.714 (1.623), MTL 1.206–1.667 (1.293), WL
1.492–1.651 (1.570), PSL 0.333–0.389 (0.354), PTH 0.322–0.378
(0.341), PPH 0.367–0.467 (0.422), PTL 0.544–0.667 (0.590), PPL
0.333–0.389 (0.360), PTW 0.211–0.267 (0.236), PPW 0.467–0.589
(0.546), PW 0.856–0.978 (0.931).
Indices CI 99–104 (101), SI 49–53 (50),
MDI 42–51 (48), PSLI 16–18 (17), PWI 43–45 (44), FI 75–80 (77),
PeI 24–27 (25), PpI 55–63 (59), PpWI 219–252 (231), PpLI 151–176
Head elliptical, longer than wide (CI 84–89), with sides of head
rounded towards relatively narrow posterior margin and head margin
posterior of eye-level in full-face view with laterally projecting
hairs. Occipital carina conspicuous, medially with a weak concavity in
full-face view. Dorsum of head smooth and shiny, hexagonally
micropunctate to very faintly punctuate. Malar space with few short
carinae next to antennal insertion ending at posterior eye-level.
Scapes moderately long (SI 139–160), pilosity basally subdecumbent to
decumbent, apically subdecumbent to suberect. Dorsopronotum in lateral
view flat, anteriorly towards neck weakly punctate, partly overlain by
some weak irregular rugulae, posteriorly grading to smooth and
relatively steep posterior declivity. Lateropronotum partly to
completely smooth and shiny. Both metanotal processes conspicuous and
well-developed, sharply angulate, metanotal groove deep and broad.
Mesopleuron and propodeum uniformly punctuate, dorso- propodeum in
lateral view level to declining gently towards base of spines.
Propodeal spines moderately long (PSLI 29–35). Petiole and postpetiole
punctate, dorsally superficially and partly smooth. Gaster smooth and
shiny, anteriorly with superficially punctate central area, in size not
larger than dorsal surface of postpetiole. Pilosity generally
abundant with long erect setae and shorter suberect to subdecumbent
hairs present. Metatibia with appressed to decumbent pilosity on inner
edge, subdecumbent on outer edge. Color medium to dark
Measurements (n=17): HL 0.772–0.878
(0.838), HW 0.667–0–756 (0.721), SL 0.989–1.206 (1.076), MDL
0.522–0.611 (0.562), EL 0.161–0.189 (0.171), MFL 1.133–1.381 (1.277),
MTL: 0.878–1.067 (0.981), WL 1.078–1.254 (1.163), PSL 0.244–0.300
(0.271), PTH 0.167–0.189 (0.179), PPH 0.189–0.222 (0.210), PTL:
0.300–0.356 (0.332), PPL 0.189–0.244 (0.220), PTW 0.106–0.128
(0.118), PPW 0 211–0.256 (0.225), PW 0.444–0.511 (0.484)
Indices: CI 84–89 (86), SI 139–160 (149), MDI 75–82 (78), PSLI 29–35
(32), PWI 66–68
(67), FI 169–189 (177), PpWI 165–211 (191), PpLI 135–176 (151).
darwini, P. batrachorum,
and P. setosa are
the only darkly colored species with minor workers possessing several
laterally projecting hairs on the head margin posterior of the
eye-level. Pheidole darwini can
be distinguished from P. batrachorum
by the following characters: lack of [darwini]
versus presence of
impressed punctures on frons and vertex,
wider head, shorter scapes, and longer spines (CI 84–89, SI 139–160,
PSLI 29–35 [darwini] versus
CI 79–86, SI 153–172, PSLI 21–29
[batrachorum]). From minor
workers of P. setosa it is
significantly narrower head margin, mostly decumbent to subdecumbent
scape pilosity versus decumbent pilosity with additional erect to
suberect hairs along outer edge, metatibia pilosity with subdecumbent
hairs along outer edge versus uniform pilosity without subdecumbent
hairs, and metafemur marginally longer (FI 169–189 versus 167–168).
The major workers are unique in their combina tion of diagnostic
characters, in particular by the three to five erect hairs along the
outer edge of the scape.
Pheidole darwini occurs
in Cameroon, Central
African Republic and Gabon. The specimens have been collected from
sifted leaf-litter and rotten logs.
Fischer, Hita Garcia & Peters (2012).