Genus Crematogaster - Subgenus Sphaerocrema
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The Ants of
Africa Genus Crematogaster - Subgenus Sphaerocrema |
| Genus Crematogaster Introduction |
Diagnostic Features - Antennae 11-jointed. Frontal carinae well developed. Petiole broadened in front, trapezoidal, sometimes truncated or rounded at the anterior angles. Postpetiole entire and without a median furrow.
Santschi's (1918d) subgenus description is at 
.
Key to Workers - not fully dichotomous in the old tradition but
separations split to groups of relatively similar morphology and colour
| ° |  Workers poorly defined and
apparently consisting of a mixture of species - type similar to kneri
but varieties in striatula group (see striatula below) |
Guinea - lamottei |
| . | Long headed queens (cf Cr. wellmani) | - |
| ° | Queen only - no images available but may well be
synonymous with angusticeps |
Mali - longiceps |
| ° |  Queen only; TL 7.5 mm, with elongated rectangular head;
propodeum unarmed but with distinct angle at transition from dorsum to
decilivity (transition simply rounded on the queen of wellmani); testaceous red with the
legs lighter and the gaster
blackish brown; photographs on
species page |
Mali - angusticeps |
| ° |  Queen only; head narrower than angusticeps; other characters
similar - no photographs available |
Senegal - stenocephala |
| . | - | |
| 1 | Propodeum with spines absent or reduced to tubercles | 2 |
| -- | Propodeum with distinct spines | 4 |
| 2 | TL 3.8-4.0 mm; propodeum with denticles; colour generally black, appendages red-brown; head wider than long | Equatorial Guinea - microspina |
| -- | Colour orange-brown darkening posteriorly but not black; head longer than wide | 3 |
| 3 |  TL 3.0-5.0 mm;
propodeum with rounded tubercles; colour
darkening posteriorly from orange-red head to brown gaster; |
Pan-African - wellmani |
| -- |  TL 2.5-3.75 mm;
propodeum with tubercles sharper and a
distinctive large bordered spiracle; colour brownish-yellow, gaster
darker |
North-east Africa - pseudinermis |
 |
Propodeum with distinct spines | - |
| 4 |
Peropodeal
spines short and
triangular |
5 |
| -- |
Propodeal spines long and sharp |
6 |
| 5 |  TL 2.8-4.5 mm;
propodeal spines
stout and fairly blunt: essentially shiny with clypeus smooth and with
an arcuate anterior
margin; colour reddish-brown, gaster darker |
Pan-African - gambiensis |
| -- |  TL 3.7-4.0 mm; head
rectangular; eyes only about one-fifth
of head length and set behind the mid-point; scape surpasses occiput by
about twice its own width; propodeal spines slender and short, only
about a third or quarter the interval between their bases; lateral
mesonotum densely reticulo-punctate; anterior of pronotum dorsum with
coarse irregular striations, finer more posteriorly, rest of insect
smooth; gaster with quite long moderately abundant pubescence; colour
black or blackish-brown, appendages lighter |
Zimbabwe - hemiceros |
| -- |  TL 2.0-2.1 mm; head
as long as wide, sides moderately
arcuate; eyes fairly convex, occupying the third quarter of the head
but relatively small; scape slightly surpassing the occiput; metanotal
declivity steep but metanotal groove shallow; weakly sculptured and
slightly dull; colour uniform red-brown; separable from Crematogaster nigeriensis by
the large subpetiolar spine, erect hairs on the pronotum and
longitudinal striation on the dorsum and sides of the propodeum |
Congo Basin - wilniger |
| -- |  TL 4.5-5.3 mm; scape
surpassing occiput by about its
maximum width; dorsum of alitrunk with strong longitudinal rugae,
running right back to rear of propodeum; colour testaceous red, gaster
slightly darker |
Somalia & Sudan - paolii |
| -- |  TL 2.3-4.5 mm; head
as long as wide, sides moderately
arcuate; eyes fairly convex, occupying the third quarter of the head
but relatively small; scape slightly surpassing the occiput; metanotal
declivity steep but metanotal groove shallow; propodeal spines about as
long as one-third the spaces between the bases, horizontal with a large
basal spiracle; a pair of erect hairs on each node of the pedicel;
pubescence sparse short slightly raised on the thorax; smooth and
shiny; colour red-brown with head and postpetiole darker, gaster
brown-black with base more or less yellow-brown |
West Africa - nigeriensis |
| Propodeal
spines long and sharp |
||
| 6 |
Promesonotum concave | 7 |
| -- | Promesonotum flat or convex | 8 |
| 7 |  TL
3.0-3.75 mm; head near square in full face view; scape surpassing the
occiput; pronotal dorsum distinctly concave; metanotal groove deep;
propodeal spines long, sharp and distinctly divergent; colour chestnut
brown, head and gaster very dark |
West Africa
& Congo Basin - concava |
| . |  |
(also, possible junior synonym lotti from Sudan) |
| Promesonotum flat or convex | - | |
| 8 |
Promesonotum distinctly convex | - 9 |
| -- |
Promesonotum flat | 12 |
| 9 | Base colour red-brown | - 10 |
| -- |
Base colour - brown-black | 11 |
| 10 |  TL 4 mm; not
obviously differing from above two other than
somewhat larger and darker brown |
CAR & Eastern Zaïre - similis |
| -- |  TL 2.7-3.0 mm; head
square, very slightly longer than
wide; scape reaching occiput; eyes slightly convex, about one-fifth of
head and placed behind the mid-line; pronotum slightly concave (less
than concava); head shiny very finely striate on gena; rest of
body mostly smooth; few erect hairs but decumbent pubescence quite
abundant, dense and erect on antennae; colour yellow brown, occiput
darker, gaster blackish in posterior half |
Zaïre - juventa |
| . |
The
following may all be forms of striatula - with at least the apical segments of the funiculus yellow contrasting with the dark scape and head |
. |
| -- | TL at least 3.5-3.8 mm = major workers? |
11 |
| -- |  TL 2.7 mm; pronotum
with fine but distinct median longitudinal
carina; propodeal spines long but quite thick with distinct down curve;
petiole quite short, as hemiceros; very dark |
northern Congo Basin - fauconneti |
| 11 |  TL
ca. 4.0; head large, sides arcuate, in profile anterior strongly domed;
scapes relatively thick; promesonotum forming a
single dome; promesonotal suture distinct; metanotal groove wide and
deep; propodeal spines slightly downcurved; distinct spiculation on
lateral mesonotum;
colour very dark red-brown, dark rust-red |
Kenya &
CAR - horatii |
| -- |  TL
3.0-3.5 mm; head
and lateral alitrunk finely but
densely striate; appendages distinctively paler yellowish; propodeal
spines moderately long and sharp, with a distinct downturn; Congo
specimens darker and somewhat larger; usually with distinctive,
contrasting, yellow apex to funiculus; larger workers have a square head |
Pan-African - striatula |
| -- |  TL 3.5-3.8 mm; eyes occupy more than the third
quarter of the head; propodeal spines slender throughout, slightly
upcurved; in dorsal view postpetiole almost square; head matt, densely
and finely striate except on the occiput; colour black; ends of tarsi
and antennae rust-brown? = striatula major worker |
Tanzania - phoenix |
| -- |  TL 3.5-4.2 mm; seems likely to be synonymous with phoenix; if so this is the senior name |
northern Congo Basin - nigrans |
| -- |  TL
4.0-4.2 mm; eyes set behind mid-point of head, frontal carinae reaching
level of eyes; head with distinct median furrow; propodeal spines
narrow & acute but seemingly shorter; petiole from above with
convex lobate sides, 1.5 x wider than long; sub-lucid, anterior of head
shiny, rest striato-punctate; castaneous, appendages brown (the MCZ
cotype has yellow funiculi) - may be a junior synonym of striatula |
Southern Sudan - zonacaciae |
| Promesonotum
flat |
||
| 12 | Heavily sculptured, with
distinct striations on head, and long propodeal spines |
13 |
| -- |
Not heavily sculptured |
14 |
| 13 |  TL 3.5 mm; propodeal spines
very long and splayed out seen from above; petiole of distinct narrow
shape; with strong
rugose sculpturation on dorsal alitrunk; colour brown-black, base of
gaster lighter |
West Africa & Congo Basin - rugosa |
| -- |
 TL 5 mm; alitrunk densely spiculat not striated; red
brown darkening from head to gaster |
East Africa - gerardi |
| 14 |
Propodeal
spines moderate and
slightly raised in profile |
15 |
| -- |
Propodeal spines long and flat
in profile |
16 |
| 15 |  TL 3.0 mm;
pronotum flat to slightly convex; metanotal
groove not impressed; petiole spines straight, moderately long and
flat; subpetiolar spine short and blunt; head very finely
longitudinally
striate; colour brown, shiny (type specimen dull); gaster with
semi-decumbent hairs on first
tergite |
West African - dakarensis |
| -- |  TL 4-6.3 mm; HW >
HL; propodeal spines very long, about 1.5 X length of propodeum dorsum;
head, alitrunk and pedicel mat, densely reticulate-punctate; slightly
brownish-red, gaster blackish |
Pan-African - bequaerti type form |
| -- |  TL 2.8 mm plus; head
very finely and densely striate, with
distinct but small hair pits, as is thorax; propodeal spines quite
robust longer than the propodeal dorsum, divergent and a little
recurved; petiole with small anterior ventral tooth; colour varying
from brownish-yellow to darker yellow-brown; posterior border of gaster
segments with a blackish border |
Congo Basin - wilwerthi |
| -- |  TL
3.4-3.8 mm; close to luctans; head wider than long; scape
slightly surpassing the occiput; propodeal spines more slender and
closer together; shiny but sculpturation of most of body more strongly
striated; colour brown more or less with reddish tinge; posterior
border of gaster segments yellowish |
Congo Basin - rugosior |
| . |
Propodeal spines
long and flat |
. |
| 16 |
Base
colour yellow or yellow-brown |
17 |
| -- |
Base colour red-brown or darker |
18 |
| 17 |  TL
3.0-3.8 mm; unusually convex eyes; scape quite thick and distinctly
wider apically; propodeal spines long, acute and
divergent but near horizontal in profile; colour piceous (?, original
description, darker than striatula),
funiculus and
tarsi rust; pubescence pallid |
West Africa & Congo Basin - zavattarii |
| -- |  TL 2.5-3.3 mm; kneri
group but pronotum shorter
and wider; scapes shorter; anterior margin of clypeus weakly impressed;
occipital margin weakly impressed; dorsum of propodeum short, spines
more robust; pronotal dorsum weakly but distinctly sculptured; colour
ferruginous-red or yellower, basal segment of gaster clear brown, rest
darker but segments with narrow yellowish borders |
West Africa, Congo Basin, Kenya - luctans |
| -- |  TL 3.0-3.5 mm; close
to kneri but head and
pronotum mostly smooth and shiny; colour testaceous yellow with apex of
abdomen blackish |
West Africa & Congo Basin - chlorotica |
| -- |  TL 4.0 mm; head rounded
slightly wider than long; pro- and
mesonotum marginate laterally; sculpturation of fine reticulation with
overlying rugulation on anterior head and alitrunk; propodeal spines
long and acute; colour yellowish, gaster darkertype form |
Pan-African - kneri |
| -- |
 TL ca 4.8 mm; dark yellow brown |
Senegal
to Congo Basin - pronotalis |
| -- |
 TL 3.4-3.6 mm; shiny |
Congo
Basin - liebknechti |
| Base colour
red-brown or darker |
||
| 18 |  TL 3.0-3.9 mm; propodeal
spines horizontal and short; head
smooth and shining with only fine striation on anterior; head and
thorax variably dull yellow, gaster dark brown; cf kneri |
South Africa - hottentota. |
| -- |  TL 3.7 mm; eyes
occupy about the third quarter of the
head; promesonotal suture very deep, pronotum convex but mesonotum
flat; propodeal spines about as long as the propodeum dorsum slightly
raised and divergent; head finely and densely striate longitudinally;
thorax with short longitudinal rugae with interspaced
rugo-reticulation; lateral alitrunk densely striate; colour
reddish-brown; mandibles, funiculus and articulations of scape and
tarsi clear rust, rest of scape tarsi and petiole more brown |
Uganda - rustica |
| -- |  TL 3.5-4.3 mm;
promesonotal suture distinct (deeper than
in kneri); mesonotum with distinct median carina; colour
dark-brown, base of gaster paler; appendages paler to reddish-brown; |
Tanzania & Zimbabwe - amita |
| -- |  TL 4.5 mm; not very
obviously different to gabonensis,
but head seemingly rather narrower; type with a dark brown head |
Congo Basin (& West Africa?) - libengensis |
| -- |  TL
4.5 (holotype); head large, sides arcuate; promesonotum forming a
single dome; promesonotal suture distinct; metanotal groove wide and
deep; propodeal spines flat and sharp as long as propodeum dorsum;
colour dark rust-red, gaster pitch brown |
West Africa
& Congo Basin - gabonensis |
 |
MYRMICINAE Introduction |
© 2007, 2008, 2009, 2010, 2011, 2013, 2015, 2016, 2017, 2018 -
Brian
Taylor
CBiol
FRSB FRES 11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K. |
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