Crematogaster (Sphaerocrema) gabonensis Emery
Type location Gabon (Emery, 1899e: 484, worker; Santschi,
1911i: 281, male); subspecies fuscitatis (Forel, 1913h:
351, worker) from Zaïre, Kondué, collected by
Luja; (see Bolton, 1995)
 .
Emery's (1899e) description is at
 .
Male first described by Santschi (1911i), from Ivory Coast,
collected by J H Lohier, 1911, with numerous workers.
WORKER - TL 2.8-3.5 mm; colour black; mandibles, antennae and
tarsi testaceous; smooth and shiny, with fine striations on the
sides of the propodeum and metapleuron. Pilosity mediocre, denser
on the propodeum. Head small, trapezoidal as wide as long,
occipital border transverse and narrowing to half the width of the
anterior of the head. Eyes very convex occupying the anterior half
of the sides. Clypeus convex with anterior border arched.
Mandibles smooth and with four teeth. Scape length as that of the
3rd funiculus segment. Alitrunk less than a quarter longer than
high, highly convex anteriorly forward of sill at midpoint. Dorsum
and declivity of the propodeum separated by a slightly angular
curve. Pedicel like that of the worker but the petiole is about
half as short, postpetiole without a median notch.
Forel (1913h) described fuscitatis as identical to the
type but - TL 3.9-5.5; colour darker brown and gaster
brownish-black. Photographs of this form can be seen below.
Wheeler (1922) also listed it (under Atopogyne) from
Ivory Coast (by Lohier) and Cameroun (at Victoria by
Fickendey).
Found on cocoa in Ghana by Majer, who found it in 3.5%
of his 144 pkd samples at Kade, with 700-800 workers per sample
(1975, 1976a, b, c). Also from cocoa mistletoe (Room, 1972a,
1975), where it ranked 13th in terms of abundance (550 workers)
but was in less than 30 of 630 samples of mistletoe/cocoa
junction. |
 It
(identified by B. Bolton) was among the dominant species studied
at Nko'emvon in Cameroun by Jackson (1984), occurring on
36% of the trees in one cocoa plot and negatively associated with
Tetramorium aculeatum. Jackson described it as being
independent of canopy density but did not mention its nest sites.
Also identified by Bolton, it was reported as one of the six most
common species on oil palm at Mpundu and Mondoni, southwestern
Cameroun, by Dejean et al (1997). At Mpundu it occupied
86% of the oil palms, and at Mondoni it was on 26.2% to 81.6% of
the palms. They noted that it builds "numerous smooth
carton nests distributed in the oil palm foliage but not against
the trunk as do other carton nest builder Crematogaster
species". The largest carton nests in their survey reached 35
cm in diameter.
The photomontages are of specimens collected in Cameroun
- south-western tropical coastal forest area between Edéa
and Campo (McKey Wolbachia project) - Cameroon 50 from
location Ebodjé, 05 April 2001, on Terminalia catappa
in village. Other images can be seen in the folder at -
Distinguishing features - Polymorphic. Overall colour deep
castaneous brown; head, antenna, especially the apical two
segments of funiculus and tarsi lighter. Head unsculptured and
polished; lateral mesonotum and propodeum including spines oblique
to longitudinally striate; otherwise all surfaces shiny but dulled
by dense decumbent pilosity. Head in full face view very like clariventris,
frontally densely but finely longitudinally striate, right across
from cheek to cheek but fading around midline to a completely
smooth occiput. Mandibles striated, apices darker, with five stout
equally sized teeth. Scapes fairly short and thick, as are
funicular segments, with segment 1 longer than next six; apical
two more enlarged to form a short thick club. Pronotum and
mesonotum dorsum convex, mesonotal carina shallow; metanotal
declivity with a vertical drop into shallow groove. Propodeum
convex in profile ahead of long, flat, sharp spines. Petiole short
and thick in lateral view, with short anterior ventral tooth. Few
erect hairs, except on anterior margin of clypeus, and where there
are erect hairs they are hardly longer or thicker than the
decumbent pilosity. Antennae, tibiae and tarsi very bristly.
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Cameroon 50 minors.
The photomontage of fuscitatis is derived from