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

Subgenus Oxygyne Forel (1901e: 375)

Diagnostic Features - Antennae 11-jointed, with 3-segmented club. Frontal carinae short. According to Santschi (1935) the workers are completely lacking in erect hairs on the dorsum of the body, save for some on the anterior of the head and on the femora.

Arnold (1920a: 542) gave a translation and comments, this is at {original description}.

Worker diagnosis of Crematogaster (Oxygyne) (Blainer, 2012)
1. In lateral view, median portion of clypeus more or less prominently convex and in full-face view medially protruding over mandibles.
2. Masticatory margin of mandibles with four teeth.
3. Fronto-clypeal suture [notch] impressed, often anterior portion of frons (above suture) transversely concave.
4. Head usually rounded and equally long as wide or slightly wider than long, cephalic index 0.97–1.18.
5. Promesonotal suture often complete and distinct.
6. Propodeal spines present.
7. Subpetiolar process absent.
8. Postpetiole with median impression.
9. Leg length variable, fairly long to moderately short, leg–body index 1.10–1.43, length of hind tibia 0.59–1.25 mm.
10. Body size highly variable, small to very large, head width 0.73–1.26 mm and Weber’s length 0.80–1.40 mm.

Blaimer, B. B. 2012. Untangling complex morphological variation: taxonomic revision of the subgenus Crematogaster (Oxygyne) in Madagascar, with insight into the evolution and biogeography of this enigmatic ant clade (Hymenoptera: Formicidae). Systematic Entomology, 37, 240–260.

Separation of species (based on historical descriptions)

1 Propodeal spines short, reduced to sharp denticles 2
- Propodeal spines relatively long and narrow 3
2 {Crematogaster margariyae}TL 2.9-3.3 mm; black-brown; shiny with sculpturation mostly of fine shagreening Cameroun & Congo Basin - margaritae
-- {Crematogaster donisthorpei}TL 3.0-3.5 mm; black to dark brown; very finely reticulate, effaced in small individuals; head longer than wide rounded behind the eyes; antennal club indistinct 4-segmented; propodeum convex, spines, short and dentiform Zimbabwe - donisthorpei
-- {Crematogaster brevamarta}TL 2.9-3.4 mm; dull black-brown; noticeably sculptured with short scapes, SI
Cameroun & Congo Basin - brevarmata
. Propodeal spines relatively long and narrow .
3 {short description of image}TL 3.5-4.0 mm; black, moderately shining; head finely but densely striate, alitrunk more coarsely longitudinally striate; no pilosity but sparse fine yellowish pubescence; mandibles narrow but with four teeth; scape surpassing occiput by one-third its length, club distinctly 3-segmented; propodeal spines very acute, as long as dorsum of propodeum South Africa - oscaris
-- Polished and shiny near black appearance 4
4 {Crematogaster trautweini}TL 3.0 mm; with overall fine spiculate sculpturation; gaster black, alitrunk and most of head brown-black, appendages reddish-brown; pronotum rounded; propodeal spines sharp Cameroun & Congo Basin - trautweini
-- {short description of image}TL < 2.0 mm; black to dark brown; almost unsculptured, very shiny; HL = HW rounded behind the eyes; antennal club 4-segmented; propodeum convex, spines relatively long and sharp Zare & South Africa - santschii
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