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

21
return to couplet #17
 * Pronotum (at the humeri) and mesonotum each with a pair of exceptionally long fine flagellate hairs. First gastral tergite with only a single pair of long simple hairs, which are not thickened or clavate apically and are situated close to the base of the sclerite. (Cameroun, Gabon, Congo, Zaire) . . . . . Strumigenys dotaja


 * Pronotum (at the humeri) with flagellate hairs but mesonotum never with such hairs. Usually the mesonotum with a single pair (very rarely 2 pairs) of stout hairs which are thickened or clavate apically. First gastral tergite with hairs that are thickened or clavate apically . . . . . 22

22
return to couplet #21
 * Cephalic dorsum behind highest point of vertex with a single pair of standing curved clavate hairs. With postpetiole in profile the area of the ventral spongiform lobe less than that of the exposed portion of the postpetiole disc. With head in full-face view the basal 4-8 denticles on the mandible often enlarged, broader longer and coarser than those preceding. (Guinea-Bissau, Guinea, Ivory Coast, Ghana, Togo, Benin, Nigeria, Cameroun , Gabon , Congo, Zaire, Angola, Sudan, Kenya, Uganda, Thnzania, Mozambique, Zimbabwe, South Africa, Madagascar, Mauritius) . . . . . Strumigenys ludovici


 * Cephalic dorsum behind highest point of vertex with two, or rarely three, pairs of standing curved clavate hairs. With postpetiole in profile the area of the ventral spongiform lobe distinctly greater than that of the exposed portion of the postpetiole disc. With head in full-face view the mandibular denticles always small fine and regular to the base. (Nigeria, Ethiopia, Kenya, Tanzania, Burundi, Uganda, Zaire, Malawi, Zambia, Zimbabwe, Mozambique, Angola, Botswana, South Africa, Madagascar, Mauritius) . . . . . Strumigenys simoni

23
return to couplet #9
 * Leading edge of scape with a row of very conspicuous projecting broadly spatulate to spoon-shaped hairs, one or more of which are distinctly curved or inclined toward the base of the scape or (rarely) all of which are at right-angles to the long axis of the scape . . . . . 24

scape), or rarely the scape without hairs of any description . . . . . 48
 * Leading edge of scape either with freely projecting simple to wire-like filiform hairs that may be straight, angled or sinuate, or leading edge of scape with fine simple to narrowly spatulate hairs only (if so then all are directed toward the apex of the

24
return to couplet #23
 * With head in full-face view exposed portions of mandibles long and narrow, only engaging near their extreme apices at full closure; proximally with an elongate gap bordered by the masticatory margins of the mandibles and the anterior clypeal margin, the labral lobes visible through the gap . . . . . 25


 * With head in full-face view exposed portions of mandibles short and triangular, engaging throughout their length at full closure; proximally without a triangular gap and the labral lobes not visible . . . . . 33

25
return to couplet #24
 * Subbasal bend of scape developed into a large anteriorly directed lobe. Spongiform tissue of waist segments vestigial or absent. Head broader than long (CI 115 or more). Anterior clypeal margin with 2-3 pairs of long strap-like or filiform hairs that project anteriorly . . . . . 26


 * Subbasal bend of scape rounded, not projecting as a large lobe. Spongiform tissue of waist segments distinctly developed. Head longer than broad (CI < 80). Anterior clypeal margin with a row of short spatulate hairs . . . . . 31

26
return to couplet #25
 * Cephalic dorsum with numerous large orbicular hairs present; highest point of vertex without a transverse row of short erect remiform hairs. Projecting row of long hairs on anterior clypeal margin broad and strap-like . . . . . 27


 * Cephalic dorsum without orbicular hairs; highest point of vertex with a transverse row of short erect remiform hairs. Projecting row of long hairs on anterior clypeal margin slender, filiform. (Gabon) . . . . . Strumigenys anorbicula

27
return to couplet #26
 * Apicodorsal tooth of mandible spiniform and extremely long, enormously longer than the ventral tooth of the apical vertical series . . . . . 28


 * Apicodorsal tooth of mandible dentiform to short spiniform, at most only fractionally longer than the ventral tooth of the apical vertical series . . . . . 29

28
return to couplet #27
 * Mandible with a single small preapical tooth that is situated very close to the apicodorsal tooth. Area of head immediately behind posterior clypeal margin with appressed small spatulate hairs; large orbicular hairs present more posteriorly on the vertex. Large hairs on leading edge of scape curved toward apex of subbasal lobe. (Ivory Coast, Ghana, Cameroun, Zaire) . . . . . Strumigenys roomi


 * Mandible with 2 preapical teeth that are situated on the distal half of the blade. Area of head immediately behind posterior clypeal margin with orbicular hairs; orbicular hairs also present more posteriorly on the vertex. Large hairs on leading edge of scape directed at right angles to long axis of scape. (Zaire) . . . . . Strumigenys mormo

29
return to couplet #27
 * Dorsal surface of mandible without flattened hairs arising from it on the distal half. Posterior half of mesonotum convex and distinctly humped in profile. (Ivory Coast, Ghana, Nigeria, Cameroun, Gabon) . . . . . Strumigenys laticeps


 * Dorsal surface of mandible with two flattened hairs arising from it on the distal half. Posterior half of mesonotum not humped in profile . . . . . 30

30
return to couplet #29
 * Mandible with a single small preapical tooth, located close to the apex. Proximal flattened hair on dorsum of mandible arising at about the midlength of the closed mandible. Outer strap-like hair on anterior clYPeal margin extending forward to the midlength of the mandible at most. (Ivory Coast, Ghana) . . . . . Strumigenys tiglath


 * Mandible with two small preapical teeth, located close to the apex. Proximal flattened hair on dorsum of mandible arising well distal of the midlength of the closed mandible. Outer strap-like hair on anterior clypeal margin extending forward well beyond the midlength of the mandible. (Gabon) . . . . . Strumigenys marchosias

33
return to couplet #24
 * With head in full-face view and the mandibles fully closed the dorsal surface of each mandible basally with a very distinct transverse sharp edge or rim running across the width of the blade, parallel to and in front of the anterior clypeal margin; the mandible surface between this rim and the clypeal margin deeply depressed. (Cosmopolitan tramp species) . . . . . Strumigenys membranifera


 * With the head in full-face view and the mandibles fully closed the dorsal surface of each mandible basally entire, without a transverse edge or rim running across the width of the blade, without a depressed area in front of the clypeal margin . . . . . 34

34
return to couplet #33
 * First gastral tergite without standing hairs of any form on the entire sclerite . . . . . 35


 * First gastral tergite with standing hairs which are usually numerous but which may be restricted to a single basal pair and a single apical pair . . . . . 37

35
return to couplet #34
 * With the head in full-face view the clypeal dorsum studded with large flattened suborbicular hairs that are as conspicuous as the marginal fringe of projecting hairs. Entire dorsum behind the clypeus densely clothed with similar suborbicular hairs. Scale-like appressed hairs sparse but obvious on dorsal alitrunk and disc of postpetiole. (Ivory Coast, Ghana, Cameroun, Gabon , Angola) . . . . . Strumigenys sharra


 * With the head in full-face view the clypeal dorsum without hairs or at most with minute appressed pubescence that is by no means as conspicuous as the marginal fringe of projecting hairs. Dorsum behind clypeus either without flattened suborbicular hairs, or with them restricted to a sharply defined transverse band immediately in front of the occipital margin . Scale-like appressed hairs absent from dorsal alitrunk and disc of postpetiole . . . . . 36

36
return to couplet #35
 * Cephalic dorsum with a transverse band of broadly scale-like to suborbicular hairs just in front of the occipital margin. Upper scrobe margin in full-face view fringed with a row of closely appressed small spoon-shaped hairs that are curved anteriorly. (Ghana) . . . . . Strumigenys chyatha


 * Cephalic dorsum without a transverse band of broadly scale-like to suborbicular hairs in front of the occipital margin . Upper scrobe margin in full-face view without fringing pilosity. (Ivory Coast) . . . . . Strumigenys impidora

37
return to couplet #34
 * With head in full-face view and mandibles fully closed the basal lamella clearly visible in front of the anterior clypeal margin; the lamella effectively separates the basalmost mandibular tooth from the line of the anterior clypeal margin. Anterior clypeal margin transverse. (South Africa) . . . . . Strumigenys transversa


 * With head in full-face view and mandibles fully closed the basal lamella invisible, completely concealed beneath clypeus; basal most mandibular teeth immediately follow anterior clypeal margin. Anterior clypeal margin usually evenly shallowly concave, less commonly transverse . . . . . 38

38
return to couplet #37
 * Base of first gastral tergite with median area distinctly depressed and concave, the sclerite with a dented appearance. First gastral tergite in dorsal view with suture line between limbus and sclerite proper distinctly arched-concave on each side of the midline. Maximum diameter of eye conspicuously greater than maximum width of scape. Scapes relatively long, SI 71-83 . . . . . 39


 * Base of first gastral tergite without a depressed concave median area. First gastral tergite in dorsal view with suture line between limbus and sclerite proper approximately transverse, or shallowly concave across the entire width, or weakly sinuate. Maximum diameter of eye at most subequal to, but usually much less than, maximum width of scape. Scapes shorter, SI 58 - 67 . . . . . 43

39
return to couplet #38
 * Mesonotal dorsum with 3-4 pairs of erect bristle-like simple or slightly flattened to weakly remiform hairs that may be straight or shallowly curved . . . . . 40


 * Mesonotal dorsum with all hairs short and spoon-shaped, strongly curved to subappressed . . . . . 42

40
return to couplet #39
 * Pronotum with erect simple hairs similar to those on mesonotum. Pronotal humerus with a laterodorsally projecting elongate simple hair. Cephalic dorsum from clypeus to highest point of vertex without conspicuous spoon-shaped hairs. With head in full-face view lateral margin of occipital lobe with freely laterally projecting simple curved hairs. (South Africa) . . . . . Strumigenys noara


 * Pronotum with small spoon-shaped hairs that are strongly curved to reclinate, without erect simple hairs such as are present on mesonotum. Pronotal humerus without an elongate simple hair. Cephalic dorsum from clypeus to highest point of vertex with very conspicuous spoon-shaped hairs. With head in full-face view lateral margin of occipital lobe with small curved spoon-shaped hairs . . . . . 41