The Ants of Africa
Genus Crematogaster - Subgenus Orthocrema
Genus Crematogaster Introduction

Subgenus Orthocrema Santschi (1918d: 182)

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 {original description}. 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
- Numerous fine erect hairs
2 n. sp. DupontL 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
-- Crematogaster sordidulaHead ovoid in full face view; scapes relatively short
Cr. 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
-- Crematogaster dolensTL 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 Crematogaster gratiosaTL 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 Zare & Gabon - gratiosa
-- Scape not or only just surpassing the occiput, eyes convex or flat 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 Creamtogaster jeanneliUnicolourous 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 Crematogaster molongoriPropodeal spines not or only slightly longer than the distance between their bases Congo & South Sudan - molongori
-- {pauciseta}Propodeal spines much longer than the distance between their bases
TL 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 --
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 {short description of image}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 {rectinota}TL 1.8-2.1 mm; petiole short, wider than long, straight-sided in dorsal view; colour pale ochreous yellow Zimbabwe - rectinota
-- {Crematogaster litoralis}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 {Crematogaster transvaaalensis}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 Crematogaster boeraTL 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 Crematogaster natalensisTL 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 {Crematogaster muralti}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
-- {Crematogaster ugandensisTL 1-8-2.2 mm; head and alitrunk lightly striated; dark brown to black Uganda - ugandensis
Contents MYRMICINAE Introduction
2007, 2008, 2009, 2010, 2013, 2015, 2016, 2018 - Brian Taylor CBiol FRSB FRES
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