Key to Afrotropical Calyptomyrmex workers

Bolton (1981) revises the genus for the Afrotropical Region. No new species have been added since then.

1

 * Hairs on first gastral tergite scale-like and with the outer edge of each hair having 15-20 freely projecting short filaments so that the margin of the hair has a fringed ray-like appearance …..Calyptomyrmex stellatus


 * Hairs on first gastral tergite variously shaped, sometimes scale-like, but never with the outer edge of each hair with freely projecting filaments giving a fringed or ray-like appearance .....2

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return to couplet .....1


 * Hair closest to apex on outer margin of clypeal fork short, stout and conspicuously thickened, usually blunt, contrasting strongly with the fine hairs which project forward from the vertical face of the clypeus below the fork. Hairs on outer margin of fork behind the apicalmost always stout and like the apicalmost hair .....3


 * Hair closest to apex on outer margin of clypeal fork elongate, simple and fine, similar in structure to the fine hairs which project forward from the vertical face of the clypeus below the fork, but shorter. Hairs on outer margin of fork behind the apicalmost either similar to the apicalmost hair or distinctly thickened .....6

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return to couplet .....2
 * Maximum diameter of eye much greater (2-4 times greater) than the maximum width of the hairs in the first transverse pronotal row .....4


 * Maximum diameter of eye at most equal to the maximum width of the hairs in the first transverse pronotal row, usually distinctly less .....5

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return to couplet .....3
 * Flattened hairs on first gastral tergite scale-like short and squat, widely scattered …..Calyptomyrmex arnoldi


 * Flattened hairs on first gastral tergite elongate and narrow, spatulate and with a tapering long basal stem, dense …..Calyptomyrmex tensus

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return to couplet .....3
 * Eyes with 5-6 facets, maximum diameter c. 0.04, about 0.05-0.06 x HW. Smaller species, HW 0.62-0.68, AL 0.60-0.64 …..Calyptomyrmex brevis


 * Eyes with more than 6 facets, maximum diameter 0.06-0.08 x HW. Smaller species, HW 0.68-0.80, AL 0.66-0.84…..Calyptomyrmex piripilis

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return to couplet .....2
 * First gastral tergite without scale-like, spatulate or clavate hairs; all hairs erect, simple, stout and acute apically…..Calyptomyrmex barak


 * First gastral tergite with scale-like, spatulate or clavate hairs present .....7

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return to couplet .....6


 * Maximum diameter of eye usually less than the maximum width of the hairs in the first transverse pronotal row, at most the widths about equal …..Calyptomyrmex kaurus


 * Maximum diameter of eye distinctly greater than the maximum width of the hairs in the first transverse pronotal row .....8

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return to couplet .....7


 * Bizarre hairs similar to those on first gastral tergite present everywhere on the first gastral sternite…..Calyptomyrmex shasu


 * Bizarre hairs similar to those on first gastral tergite restricted to the posterior one-third of the first gastral sternite or entirely absent from the first sternite .....9

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return to couplet .....8


 * With first gastral tergite in dorsal view the hairs squamate scale-like to tear drop shaped, without a long tapering basal stem .....10
 * With first gastral tergite in dorsal view the hairs not squamate, either elongate-clavate, long spatulate or Indian club-shaped, with a long tapering basal stem .....12

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return to couplet .....9


 * Large species, HW 0.78-0.98, PW 0.54-0.68 with abundant large squamate hairs. On the first gastral tergite the width of each hair about equal to or greater than the distance to the hairs on each side of it. Mandibles longitudinally striated, usually sharply and conspicuously so …..Calyptomyrmex nummuliticus


 * Smaller species, HW 0.56-0.70, PW 0.40-0.50 with small squamate hairs. On the first gastral tergite the width of each hair distinctly less than the distance to the hairs on each side of it. Mandibles smooth or with vestigial marking, not longitudinally striate .....11

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return to couplet .....10


 * Dorsum of head predominantly longitudinally rugulose, with a reticulum occipitally but without a triangular area on the vertex which is transversely rugulose …..Calyptomyrmex nedjem


 * Dorsum of head with longitudinal rugulae on each side which diverge towards, with a reticulum occipitally but with a triangular area on the vertex which is transversely rugulose …..Calyptomyrmex foreli

12
return to couplet .....9


 * Hairs on outer margin of clypeal fork behind the apicalmost hair as fine as the apicalmost, similar in appeareance. Clavate hairs on first gastral tergite very long and slender, longer than the maximum diameter of the eye …..Calyptomyrmex rennefer


 * Hairs on outer margin of clypeal fork behind the apicalmost hair much stouter than the apicalmost, very different in appearance. Clavate hairs on first gastral tergite stout, at most only slightly longer than the maximum diameter of the eye, usually shorter. .....13

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return to couplet .....12


 * Propodeal dorsum strongly transversely rugose, without reticulate-punctuate sculpture. Larger species, HW 0.76-0.82, PW 0.52-0.60 …..Calyptomyrmex duhun


 * Propodeal dorsum reticulate-punctuate, without strong transverse rugae but sometimes with one to two very feeble irregular rugulae. Smaller species, HW 0.52-0.66, PW 0.34-0.50 .....14

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return to couplet .....13
 * Postpetiole in dorsal view distinctly broader and more massively developed than the petiole. Eyes with 15 or fewer ommatidia .....15


 * Postpetiole and petiole in dorsal view of approximately equal widths, the former not obviously broader than the latter. Eyes with 18 to > 20 ommatidia …..Calyptomyrmex clavatus

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return to couplet .....14
 * Larger species, HW 0.64 or more. Prongs of clypeal fork long, their outer edges not strongly bowed outwards …..Calyptomyrmex brunneus


 * Smaller species, HW 0.52-0.60, PW 0.34-0.42. Prongs of clypeal fork short and stout, their outer edges strongly bowed outwards …..Calyptomyrmex claviseta