Key to Afrotropical Strumigenys (as Pyramica)

This worker key is based on: Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028.

Bolton noted: The socially parasitic P. inquilina (Strumigenys inquilina), known only from queens found in a nest of P. lujae, (Strumigenys lujae) is omitted from the key; comparative notes on the queens are given under inquilina.

This key is from a revision study that included the now synonymized genus Pyramica. Therefore there are two keys that treat two sets of Strumigenys species, the key found below (the group of species once classified as Pyramica) and a key to Afrotropical Strumigenys.

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1

 * Antenna with 4 segments; the first funicular segment followed directly by the 2-segmented club . . . . . 2


 * Antenna with 6 segments; the first funicular segment separated from the 2-segmented club by two much smaller segments . . . . . 9

2
return to couplet #1
 * Mandibles linear, elongate and narrow, without preapical teeth; MI > 25. At full closure mandibles engage only at their extreme apices and enclose a large open space between the blades; labral lobes visible between mandibles even at full closure. Cephalic dorsum with small orbicular hairs present; CI 1 00 - 107. (Ghana, Cameroun, Uganda) . . . . . Strumigenys minima


 * Mandibles short and triangular, with preapical teeth; MI 6-17. At full closure mandibles engage throughout their visible length, without a space between the blades; labral lobes not visible when mandibles fully closed . Cephalic dorsum without orbicular hairs; CI 51-88 . . . . . 3

3
return to couplet #2
 * Anterior clypeal margin convex in full-face view. Pronotal humerus with a long flagellate or stiffly projecting specialised hair. Hairs on leading edge of scape fine to narrowly spatulate, all curved toward scape apex . Basal lamella of mandible a low lobe and principal dental row with 7 teeth . . . . . 4


 * Anterior clypeal margin concave in full-face view. Pronotal humerus without a specialised projecting hair of any form . Hairs on leading edge of scape broadly spatulate to spoon-shaped, one or more distinctly curved toward the scape base. Basal lamella of mandible a long narrow triangle that may be truncated apically and principal dental row with 5 teeth . . . . . 6

4
return to couplet #3
 * Clypeus broad, its lateral margins approximately parallel. With head in full-face view the outer margins of the fully closed mandibles intersect the anterior clypeal margin mesad of the anterolateral clypeal angles, so that there is a section of the anterior clypeal margin that projects laterally beyond the outline of the mandible. Dorsum of clypeus without hairs. (Ivory Coast, Ghana, Kenya, Tanzania, Zimbabwe, South Africa) . . . . . Strumigenys marginata


 * Clypeus narrow, its lateral margins more or less evenly convergent anteriorly. With the head in full-face view the outer margins of the fully closed mandibles intersect the anterior clypeal margin at the anterolateral clypeal angles, so that there is no section of the anterior clypeal margin that projects laterally beyond the outline of the mandible. Dorsum of clypeus with abundant short curved hairs . . . . . 5

5
return to couplet #4
 * Pronotum sharply marginate dorsolaterally, the dorsum un sculptured. Hairs on clypeal dorsum spatulate. Metanotal groove indistinct to absent. Ventral lobe of postpetiole spongiform . Small species with short scape and broad head, HL 0.42-0.46, SI 61-67, CI 65-70. (Ivory Coast, Ghana, Cameroun , Gabon , Zaire, Uganda) . . . . . Strumigenys tacta


 * Pronotum not marginate dorsolaterally, the dorsum weakly sculptured. Hairs on clypeal dorsum simple. Metanotal groove broad and deeply impressed. Ventral lobe of postpetiole laminate. Larger species with very long scape and narrow head, HL 0.74, SI 116, CI 51. (Cameroun) . . . . . Strumigenys vodensa

6
return to couplet #3
 * Entire body coloured with broad alternating yellow and black transverse bands. Basigastral costulae form a continuous row across the tergite, without a central noncostulate area. Ventral spongiform crest of petiolar peduncle absent between insertion and node. (Ivory Coast, Ghana, Cameroun, Gabon) . . . . . Strumigenys tigrilla


 * Body uniformly coloured, without alternating yellow and black broad transverse bands. Basigastral costulae radiate from each side of a non-costulate central area. Ventral spongiform crest of petiolar peduncle complete from insertion to apex of segment . . . . . 7

7
return to couplet #6
 * With head in profile the dorsum with a pair of short erect hairs close to the occipital margin. (Kenya, Tanzania, Angola, South Africa, Madagascar) . . . . . Strumigenys mandibularis


 * With head in profile the dorsum without erect hairs . . . . . 8

8
return to couplet #7
 * Anterior half of clypeus with a broad longitudinal impression mid-dorsally which is filled with short scale-like hairs that are directed toward the midline. Subbasal bend of scape extensively developed, its anterior margin strongly angular. Pronotal dorsum with dense fine longitudinal rugulae or costulae. (Ivory Coast, Ghana) . . . . . Strumigenys fulda


 * Anterior half of clypeus without a longitudinal impression mid-dorsally, this area without short scale-like hairs that are directed toward the midline. Subbasal bend of scape weakly developed, its anterior margin evenly rounded and not angled. Pronotal dorsum smooth or at most with faint superficial shagreening on the glossy surface. (Ivory Coast, Ghana, Nigeria, Chad, Cameroun, Gabon , Zaire, Uganda) . . . . . Strumigenys ninda

9
return to couplet #1
 * Apical (masticatory) margin of mandible serially minutely multidenticulate or serrate, with a continuous row of well over 25 tiny denticles or a continuous finely saw-like edge. Clypeus with two anterior margins: a lower secondary margin that is convex, thinly lamellate and difficult to see, and a broader, more conspicuous primary (true) margin from which anteriorly directed hairs arise, close behind and slightly above the secondary margin . . . . . 10


 * Apical (masticatory) margin of mandible not serially minutely multidenticulate nor serrate, with distinctly fewer than 20 teeth and denticles and lacking a continuous finely saw-like edge. Clypeus with a single anterior margin; without a thinly lamellate lower secondary margin that projects farther anteriorly than the primary (true) margin . . . . . 23

10
return to couplet #9
 * Apicoscrobal hair absent: with the head in full-face view the dorsolateral margin at about the level of the apex of the scrobe without a freely laterally projecting specialised hair . . . . . 11


 * Apicoscrobal hair present: with the head in full-face view the dorsolateral margin at about the level of the apex of the scrobe with a freely laterally projecting long flagellate or fine simple hair . . . . . 17

11
return to couplet #10
 * Pronotal humerus with a freely projecting hair, which may be short and straight or long and flagellate . . . . . 12


 * Pronotal humerus lacking a freely projecting straight or flagellate hair . . . . . 14

12
return to couplet #11
 * Pronotal humerus with a short stout clavate hair. Mandibles shorter, MI 26, the basal 4-5 denticles suddenly and conspicuously enlarged. Metanotal groove not impressed. (Ghana) . . . . . Strumigenys miccata


 * Pronotal humerus with a long fine flagellate hair. Mandibles longer, MI 32 - 45, the basal 4 - 5 denticles not enlarged . Metanotal groove impressed . . . . . 13

13
return to couplet #12
 * Mandibles and scapes relatively long, MI > 40, SI > 120. All hairs on leading edge of scape curved toward the scape apex. Cephalic dorsum with a transverse row of 4 erect hairs along the occipital margin, but without a pair of erect hairs anterior to this row. Mesopleuron entirely reticulate-punctate. (Cameroun) . . . . . Strumigenys sulumana


 * Mandibles and scapes relatively short, MI < 40, SI 100 or less. Some hairs on leading edge of scape curved toward the scape base. Cephalic dorsum with a transverse row of 2 or 4 erect hairs along the occipital margin, and with a pair of erect hairs anterior to this row, at about the highest point of the vertex . Mesopleuron mostly or entirely smooth and shining. (Cameroun, Zaire) . . . . . Strumigenys bequaerti

14
return to couplet #11
 * Pronotal dorsum sculptured, either costulate or reticulate-punctulate, or with a mixture of these . . . . . 15


 * Pronotal dorsum utterly lacking sculpture, glassy smooth everywhere . . . . . 16

15
return to couplet #14
 * Vertex in profile with 2 - 3 pairs of stout standing hairs. Pronotal dorsum densely sharply costulate, the spaces between costulae smooth and glossy. Pronotal ground pilosity of numerous curved broadly spatulate hairs that are very conspicuous. Upper scrobe margins delimited by broad projecting flanges that do not peter out posteriorly. (Ivory Coast, Ghana, Nigeria, Cameroun, Annobon I., Congo, Zaire, Angola, Burundi, Uganda, Kenya, Tanzania, Zimbabwe, South Africa) . . . . . Strumigenys maynei


 * Vertex in profile with a single pair of stout standing hairs. Pronotal dorsum sparsely weakly costulate, the spaces between costulae reticulate-punctate to shagreenate and dull. Pronotal ground-pilosity of sparse narrowly spatulate hairs that are difficult to see. Upper scrobe margins delimited by narrow edges that peter out posteriorly. (Cameroun, Gabon) . . . . . Strumigenys depilosa

16
return to couplet #14
 * Mesonotum in dorsal view with elevated and strongly prominent anterolateral angles. Mesonotum and dorsum of propodeum without sculpture, as smooth and shiny as pronotum . With head in profile the scrobe deep and strongly defined throughout, its dorsal margin a continuous very sharply projecting flange to its apex. Head broader and scape shorter, CI 90, SI 73 - 74. (Cameroun) . . . . . Strumigenys geoterra


 * Mesonotum in dorsal view without elevated prominent anterolateral angles. Mesonotum and dorsum of propodeum finely reticulate-punctate, not as smooth and shiny as pronotum. With head in profile the scrobe shallow and fading out posteriorly, its dorsal margin hardly discernible posterior to level of eye. Head narrower and scape longer, CI 74 - 75, SI 86 - 89 . (Gabon) . . . . . Strumigenys lucifuga

17
return to couplet #10
 * Principal sculpture of pronotal dorsum consisting of superficial to dense reticulate-punctation, with or without overlying costulate or striate sculpture. When such overlying sculpture is present it is distinctly secondary to the dense punctate component . . . . . 18


 * Principal sculpture of pronotal dorsum consisting of longitudinal to oblique costulae or striae, or the surface mostly to entirely un sculptured and smooth ; punctate sculpture usually absent but when present is very feeble and distinctly secondary to the costulate or striate component . . . . . 21

18
return to couplet #17
 * With the head in full-face view the basal series of 4 - 8 denticles on the mandible suddenly enlarged, broader longer and coarser than those preceding; usually this enlarged series very distinct, especially when mandibles open. (Guinea-Bissau, Guinea, Ivory Coast, Ghana, Togo, Benin, Nigeria, Cameroun, Gabon, Congo, Zaire, Angola, Sudan, Uganda, Kenya, Thnzania, Mozambique, Zimbabwe, South Africa, Madagascar, Mauritius) . . . . . Strumigenys ludovici


 * With the head in full-face view the basal series of denticles on the mandible not enlarged, the denticles either approximately the same size throughout the length of the mandible or very evenly and gradually increasing in size basally . . . . . 19

19
return to couplet #18
 * Mesonotum with 3 - 4 pairs of short erect stiff hairs, the posteriormost pair situated at or close to the metanotal groove. Ground-pilosity of promesonotum strong, not reclinate, conspicuous in profile. Punctate sculpture of head and alitrunk strong and sharply defined. (Ivory Coast, Ghana, Nigeria, Cameroun, Gabon , Sao Tome & Principe, Congo, Zaire, Angola, Sudan, Kenya, Chad, Uganda, Burundi) . . . . . Strumigenys serrula

of promesonotum feeble, mostly or entirely reclinate, inconspicuous in profile. Punctate sculpture on head and alitrunk usually fine . . . . . 20
 * Mesonotum usually with a single pair of erect, apically thickened to strongly clavate hairs, situated anteriorly on the sclerite. Very rarely a second pair present but if so these are very close to the first pair and remote from the metanotal groove. Ground pilosity

20
return to couplet #19
 * With head in profile cephalic dorsum with a pair of relatively slender simple standing hairs in front of highest point of vertex; 4 similar hairs present near occipital margin. With the head in full-face view the upper scrobe margins not indented at the site of the apicoscrobal hair. Postpetiole in profile with more than one pair of standing hairs. (Guinea, Ivory Coast, Ghana, Nigeria, Cameroun, Gabon, Zaire, Sao Tome & Principe, Equatorial Guinea, Angola, Sudan, Kenya, Uganda, Rwanda, Burundi, Kenya, Thnzania, Mozambique, Zimbabwe, South Africa) . . . . . Strumigenys lujae


 * With head in profile cephalic dorsum without standing hairs in front of highest point of vertex; 2-4 apically thickened to clavate standing hairs present near occipital margin. With head in full-face view the upper scrobe margins usually conspicuously indented at the site of the apicoscrobal hair. Postpetiole in profile with only a single pair of standing hairs. (Guinea, Ivory Coast, Ghana, Cameroun, Equatorial Guinea, Gabon, Zaire, Angola, Chad, Kenya, Uganda) . . . . . Strumigenys concolor