Genus Crematogaster - Subgenus Orthocrema
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The Ants of
Africa Genus Crematogaster - Subgenus Orthocrema |
| Genus Crematogaster Introduction |
Diagnostic Features - Antennal club 2-jointed. Frontal carinae well developed. Petiole with parallel sides, usually straight or scarcely arcuate, rarely broader posteriorly than anteriorly. Postpetiole entire.
Santschi's (1918d) subgenus description is at 
. Described by Bernard (1952) as primarily
oriental, small ants, often soil-inhabiting, considered as the most
primitive of the genus by virtue of the petiole structure.
Key to workers
| 1 | Overall with numerous fine erect hairs; head more circular than square; promesonotum marginate and wider in front than long; in dorsal view petiole quadrate and straight-sided; erect hairs quite abundant and slender | 2 |
| -- | With few or no erect hairs |
3 |
| - | Numerous fine erect hairs |
-- |
| 2 |  L ca 2.7 mm, HL 0.62, HW 0.57, SL 0.65, PW 0.35; CI 91,
SI 107. Head sub-square
with rounded occipital corners;
scapes long; propodeal spines long and slender; postpetiole entire and
slightly
narrower in dorsal view than the petiole; abundant quite long, fine,
erect pilosity on all surfaces, including the scapes; colour dark brown
with mandibles, legs, apex of scapes and funiculi lighter orange-brown. |
Ivory Coast - n. sp. Dupont |
| -- |  Head ovoid in full face view; scapes relatively shortCr. sordidula marocana type TL ca. 2.8 mm, HL 0.60, HW 0.54, SL 0.47, PW 0.35; CI 92, SI 89. |
Circum-mediterranean - sordidula |
| -- |  TL 2.8 mm; eyes convex but
petiole longer; propodeal spines long but not longer than the interval
between their bases; body near smooth and shiny, two or three rugae or
reticulae effaced on alitrunk dorsum; reddish to yellowish brown,
gaster brown |
Tanzania - dolens |
| -- | Few erect hairs |
-- |
| 3 |  TL 2.2 mm; with long
scapes, surpassing occiput, and
convex elongated eyes; head rectangular, as long as wide; eyes convex,
elongated, as long as a third of the head and placed in the posterior
third; scape arcuate surpassing posterior border of head; pronotum
bordered transversely with distinct anterior angles; propodeal spines
about 2/3 as long as basal interval, recurved apically; thorax with
three pairs of erect hairs, one pair on each node of pedicel; shiny,
anterior of cheeks and mesopleuron finely striate; colour red-brown,
appendages and anterior half of gaster yellowish, rest of gaster
blackish |
Zaïre & Gabon - gratiosa |
| -- | Scape not or only just surpassing the occiput, eyes convex or flat | 4 |
| 4 |
Alitrunk flat to slightly concave; few erect hairs in pairs on alitrunk and pedicel; relatively long propodeal spines | 5 |
| -- | Alitrunk convex; no or only short propodeal teeth | 7 |
| -- | Alitrunk flat to slightly concave; few erect hairs in pairs on alitrunk and pedicel; long propodeal spines | -- |
| 5 |  Unicolourous black; TL 3 mm;
head regularly and finely longitudinally striate but with median smooth
strip; most of rest of body reticulo-punctate; erect pilosity whitish,
set out in pairs on each segment of alitrunk and pedicel; shiny black,
mandibles and tarsi brown |
Kenya - jeanneli |
| -- | Other than unicolourous black | 6 |
| 6 |  Propodeal spines not or only slightly longer
than the distance between their bases |
Congo & South Sudan - molongori |
| -- |  Propodeal spines much longer
than the distance between their basesTL 2.0-2.6 mm; head wider than long, angles rounded; eyes placed well back; scape robust and surpassing occiput; club two-segmented; alitrunk distinctly bordered; propodeum with a small circular spiracle, the spines long and straight angled upward posteriorly; pubescence fine and sparse, erect hairs slender and obtuse; few and short on anterior of head, on alitrunk three pairs of large long hairs placed on lateral border placed as shown; petiole and postpetiole each with one pair; gaster with only narrower hairs; smooth and shiny, sides of alitrunk reticulate, pedicel and gaster finely punctate; colour testaceous yellow, gaster more brown-red; |
West Africa & Congo Basin - pauciseta |
| -- | Alitrunk convex; no or only short propodeal teeth | -- |
| 7 |
Head more circular than square; promesonotum marginate and wider in front than long; in dorsal view petiole quadrate and straight-sided; erect hairs quite abundant and slender | 8 |
| -- | Head rectangular; petiole not quadrate in dorsal view | 10 |
| 8 |  Without propodeal
spines; TL 2.2-2.5 mm; scape reaching
occiput; reddish-yellow, head brownish, gaster bright yellow |
Comoro Is - voeltzkowi |
| -- | With short, sharp propodeal spines | 9 |
| 9 |  TL 1.8-2.1 mm; petiole short,
wider than long, straight-sided in dorsal view; colour pale ochreous
yellow |
Zimbabwe - rectinota |
| -- |  TL
2.0-2.2 mm; eyes flat, placed posterior of mid-point and about
one-quarter length of face; petiole straight-sided but longer than
wide; colour generally ochreous but posterior border of first gastral
segment and rest of gaster black; pubescence very sparse and yellowish,
few erect hairs (no type photos) |
Kenya - litoralis |
| -- | Head rectangular; petiole not quadrate in dorsal view | -- |
| 10 |  Head longer than
wide; TL 2.7-2.8 mm; head rectangular,
wider behind; eyes large in posterior third; pronotum fairly distinctly
marginate and with small longitudinal median carina; metanotal suture
shallow; propodeal spines short; colour dark castaneous-brown,
appendages lighter; erect pilosity sparse and fairly coarse |
South Africa - transvaalensis |
| -- | Head square not longer than wide | 11 |
| 11 |  TL 2.8-2.9 mm; body colour all
over black; head square; eyes as large as one-fifth of face, placed in
posterior third; scape reaches posterior sixth of head; promesonotum
with convex profile; cheeks and thorax longitudinally striate; colour
black; appendages brownish; |
Zimbabwe - boera |
| -- | TL no more than 2.5 mm | 12 |
| 12 |  TL 2.0-2.5 mm;
promesonotum narrower and longer not wider
in front than long; colour yellowish anteriorly and no more than
reddish-brown |
South Africa - natalensis |
| Promesonotum wider in front than long | 13 | |
| 13 |  TL 2.2-2.4 mm; metanotal groove
deep and narrow; sculpturation on pronotum and lateral mesonotum of
distinct fine longitudinal striations; pubescence of thin decumbent
yellowish hairs very scanty; erect hairs yellowish few on thorax and
petiole, more on the gaster, where they are slightly clavate; shiny;
colour piceous; appendages brownish-yellow |
West Africa & Central African Republic - muralti |
| -- |  TL 1-8-2.2 mm; head and
alitrunk
lightly striated; dark brown to black |
Uganda - ugandensis |
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MYRMICINAE Introduction |
© 2007, 2008, 2009, 2010, 2013, 2015, 2016, 2018 - Brian
Taylor
CBiol
FRSB FRES 11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K. |
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