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
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Key to Workers
| ° | Workers poorly defined and apparently consisting of a mixture of species - type similar to kneri but varieties in striatula group | Guinea - lamottei |
| ° | queen only | Mali - longiceps |
| ° | queen only; TL 7.5 mm, with elongated rectangular head; propodeum unarmed; testaceous red with the legs lighter and the gaster blackish brown (perhaps the female of wellmani) | Mali - angusticeps |
| ° | queen only | 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; |
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| . |  |
Pan-African - wellmani |
| -- |  TL
2.5-3.75 mm; propodeum with tubercles sharper and a distinctive large
bordered spiracle; colour brownish-yellow, gaster darker |
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| . |  |
North-east Africa - pseudinermis |
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Propodeum with distinct spines | - |
| 4 |  Propodeal
spines stout and fairly blunt: TL 2.8-4.5 mm; essentially shiny with
clypeus smooth and with an arcuate anterior margin; colour
reddish-brown, gaster darker |
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| . |  |
Pan-African - gambiensis |
| -- | Propodeal spines sharp | 5 |
| 5 | Promesonotum concave | 6 |
| -- | Promesonotum flat or convex | 7 |
| 6 |  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) |
| -- |  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 |
| -- |  TL
4 mm; not obviously differing from above two other than somewhat larger
and darker brown |
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| . |  |
CAR & Eastern Zaïre - similis |
| Promesonotum flat or convex | - | |
| 7 | Promesonotum distinctly convex | striatula-group - 8 |
| -- | Promesonotum flat | kneri-group - 13 |
| 8 | Base colour brown or darker | 9 |
| -- | Base colour reddish | 11 |
| 9 |  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 |
| -- |  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
4.0-4.2 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 |
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| . |  |
Southern Sudan - zonacaciae |
| -- | Unicolorous brown | 10 |
| 10 |   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 finely longitudinally striate;
colour brown, shiny |
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| . |  |
Pan-African - bequaerti |
| -- |  TL
3.0-3.5 mm; head and lateral alitrunk finely but densely striate;
appendages distinctively paler yellowish; Congo specimens darker and
somewhat larger |
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| . |  |
Pan-African - striatula |
| Base colour reddish | - | |
| 11 |  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; |
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| . |  |
Somalia - paolii |
| -- | Colour red-brown | 12 |
| 12 |  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 |
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| . |  |
West Africa & Congo Basin - nigeriensis |
| -- |  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-Congo Basin - rustica |
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Promesonotum flat - kneri group | - |
| 13 |  Petiole
of distinct narrow shape; TL 3.5 mm; with strong rugose sculpturation on
dorsal alitrunk; colour brown-black, base of gaster lighter |
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| . |  |
West Africa & Congo Basin - rugosa |
| -- | Petiole essentially triangular | 14 |
| 14 | Base colour black or blackish | 15 |
| -- | Base colour brown, a shade of red-orange or lighter | 17 |
| 15 |  TL
3.0-3.8 mm; unusually convex eyes; propodeal spines long, acute and
divergent; colour piceous but cotype (in photo) much lighter
?, darker than striatula, funiculus and tarsi rust;
pubescence pallid |
. |
| . |  |
West Africa & Congo Basin - zavattarii |
| -- |  Pronotum
with fine but distinct median longitudinal carina; propodeal spines long
but quite thick with distinct downcurve; petiole quite short, as hemiceros;
very dark |
northern Congo Basin - fauconneti |
| -- | Propodeal spines short | 16 |
| 16 |  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 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 | Tanzania - phoenix |
| Base colour brown or lighter | - | |
| 17 | Base colour brown | 18 |
| -- | Base colour lighter | 19 |
| 18 |  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 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 |
| 19 |  TL
2.5-3.3 mm; kneri group but pronotum shorter and wider; scapes
shorter; anterior margin of clypeus weakly impressed; occiptal 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 - luctans |
| -- | Base colour yellowish | 20 |
| 20 | Head and alitrunk essentially smooth and shiny | 21 |
| -- | Head and alitrunk distinctly sculptured | 22 |
| 21 |  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
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 |
| 22 |   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 darker |
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| . |  |
Pan-African - kneri |
| -- |  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 |
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| . |  |
Congo Basin - wilwerthi. |
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MYRMICINAE Introduction | © 2007, 2008 - Brian Taylor CBiol
FIBiol FRES 11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K. |
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