Key to Malagasy 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.

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

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Strumigenys

1

• Antenna with 4 segments; the first funicular segment followed directly by the 2-segmented club. (Also widespread in eastern and southern Africa) . . . . . Strumigenys maxillaris

Strumigenys maxillaris

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

2

return to couplet #1

• 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 . . . . . 3

• Leading edge of scape with fine simple to narrowly spatulate hairs, all of which are directed toward the apex of the scape, or the scape without hairs . . . . . 9

3

return to couplet #2

• Mandible without a differentiated basal lamella. 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 just above the secondary margin . . . . . 4

• Mandible with a differentiated basal lamella. 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 . . . . . 5

4

return to couplet #3

• With head in full-face view the basal series of 4 - 8 denticles on the mandible suddenly enlarged, broader longer and coarser than those preceding. With postpetiole in profile the area of the ventral spongiform lobe less than that of the exposed portion of the postpetiole disc. Dorsum of head behind highest point of vertex with a single pair of standing curved clavate hairs. (Also widespread in Afrotropical region) . . . . . Strumigenys ludovici

• With head in full-face view the mandibular denticles small fine and regular to the base. With postpetiole in profile the area of the ventral spongiform lobe distinctly greater than that of the exposed portion of the postpetiole disc. Dorsum of head behind highest point of vertex with two, or rarely three, pairs of standing curved clavate hairs. (Also widespread in Afrotropical region) . . . . . Strumigenys simoni

5

return to couplet #3

• Pronotal humerus without a projecting hair. First gastral tergite without standing hairs. Cephalic dorsum with a single pair of short standing hairs present, at highest point of the vertex . Dorsal surface of each mandible basally with a very distinct transverse sharp edge or rim running across the width of the mandible, parallel to and in front of the anterior clypeal margin. (Cosmopolitan tramp species) . . . . . Strumigenys membranifera

• Pronotal humerus with an elongate simple or flagellate projecting hair. First gastral tergite with numerous standing hairs. Cephalic dorsum with a transverse row of 4 erect simple hairs, close to occipital margin. Dorsal surface of each mandible basally entire, without a transverse edge or rim running across the width of the mandible . . . . . 6

6

return to couplet #5

• Pronotal humerus with a long fine flagellate hair. Dorsum and declivity of propodeum as sharply reticulate-punctate as the mesonotum . . . . . Strumigenys ambatrix

• Pronotal humerus with a straight to shallowly curved elongate simple hair that may be blunt or acute apically. Dorsum and declivity of propodeum smooth or faintly superficially reticulate, distinctly less strongly sculptured than the mesonotum or the latter itself not sharply reticulate-punctate . . . . . 7

7

return to couplet #6

• With petiole in profile the ventral spongiform strip becoming shallower anteriorly but remaining well developed along the entire length of the segment . . . . . Strumigenys symmetrix

• With petiole in profile the ventral spongiform strip well developed beneath the node but vestigial or absent beneath the peduncle . . . . . 8

8

return to couplet #7

• With postpetiole in dorsal view the lateral margins of the disc approximately straight and strongly convergent posteriorly; in same view ventral spongiform lobe broadly projecting beyond outline of anterior margin and anterolateral angles of disc. Eye of 1 or 2 ommatidia . . . . . Strumigenys fautrix

• With postpetiole in dorsal view the lateral margins of the disc convex and only weakly convergent posteriorly; in same view ventral spongiform lobe not or only minutely projecting beyond outline of anterior margin and anterolateral angles of disc. Eye of 4 or 5 ommatidia . . . . . Strumigenys victrix

9

return to couplet #2

• Apical (masticatory) margin of mandible with a long, shallowly concave diastema between basal lamella and basal tooth that appears as a subovate edentate gap between the proximal halves of the fully closed mandibles. Alitrunk in profile short and high, with distinct promesonotal and propodeal convexities separated by an impressed metanotal groove. With petiole in profile its ventral spongiform strip vestigial, only a small fraction of the depth of the peduncle . . . . . 10

• Apical (masticatory) margin o f mandible without a diastema between basal lamella and basal tooth; dentition continuous, without a subovate edentate gap proximally between the fully closed mandibles. Alitrunk in profile long and low, without promesonotal and propodeal convexities separated by a distinct metanotal groove. With petiole in profile its ventral spongiform strip well developed , at least equal in depth to the depth of the peduncle . . . . . 11

10

return to couplet #9

• Propodeum unarmed; propodeal declivity with a carina or narrow lamella but this terminates apically and is not produced into a sharp triangular tooth . . . . . Strumigenys erynnes

• Propodeum armed; propodeal declivity with a narrow lamella that i s produced apically into a freely projecting sharp triangular tooth . . . . . Strumigenys tathula

11

return to couplet #9

• Anterior clypeal margin transverse. With head in ventral view, or in dorsal view with mandibles open, the labrum terminating anteriorly in a pair of broad flat lobes that are divergent anteriorly and broadly bluntly rounded apically. Mandible with 10 teeth and denticles in total. . . . . . Strumigenys olsoni

• Anterior clypeal margin conspicuously convex . With head in ventral view, or in dorsal view with mandibles open , the labrum terminating anteriorly in a pair of narrow lobes that are linear, digitate or triangular in shape and do not diverge anteriorly (often slightly convergent apically), the lobes very narrowly rounded to acute at their apices. Mandible with 1 2 or more teeth and denticles in total . . . . . 12

12

return to couplet #11

• With head in full-face view the side behind the level of the eye with 2 or more freely laterally projecting hairs. Promesonotum with more than three pairs of hairs. Ventral surface of each femur with a spaced row of suberect freely projecting hairs . . . . . 13

• With head in full-face view the side behind the level of the eye without freely laterally projecting hairs (one or two may occur projecting posteriorly from the occipital margin). Promesonotum hairless or at most with 3 pairs of very short fine erect hairs, two pairs on pronotum and one on mesonotum. Ventral surfaces of femora lacking spaced rows of suberect freely projecting hairs . . . . . 14

13

return to couplet #12

• In profile the promesonotum with sharp longitudinal margination separating the flat dorsum from the vertical sides. Petiole node in profile with anterior face subequal in length to the short posteriorly sloping dorsum. Hairs on head and promesonotum flagellate. Eye with only 2 - 3 ommatidia in total . . . . . Strumigenys khakaura

• In profile the promesonotum without margination , the convex dorsum rounding into the sides. Petiole node in profile with anterior face very much shorter than the long shallowly convex dorsum . Hairs on head and promesonotum short and simple. Eye with more than 10 ommatidia in total . . . . . Strumigenys seti

14

return to couplet #12

• Dorsum of head with several pairs of erect hairs behind the highest point of the vertex but without a group of 4 short erect hairs arranged at the comers of a small square around the highest point. Propodeal teeth in profile with at least half their length projecting beyond the lamella. Lateral spongiform lobes of petiole vestigial . . . . . Strumigenys hathor

• Highest point of vertex with a group of 4 short erect hairs arranged at the comers of a small square around the highest point, without pairs of erect hairs on head behind this. Propodeal teeth in profile mostly or entirely confluent with the lamella, at most only the extreme tip of the tooth projecting. Lateral spongiform lobes of petiole strongly developed . . . . . 15

15

return to couplet #14

• With petiole in profile the lateral spongiform lobe commencing behind the level of the anterior face of the node. In dorsal view the lateral spongiform lobes of the petiole terminating posterior to the level of the spiracles. Dorsal length of petiole node (discounting the posterior collar) shorter than the postpetiole disc. Larger species, HW 0.55-0 .62, AL 0.86-0.96 . . . . . Strumigenys exiguaevitae

• With petiole in profile the lateral spongiform lobe commencing at or slightly in front of the level of the anterior face of the node. In dorsal view the lateral spongiform lobes of the petiole extending forward to the level of the spiracles. Dorsal length of petiole node (discounting posterior collar) longer than the postpetiole disc. Smaller species, HW 0.41-0.47, AL 0.68-0.78 . . . . . Strumigenys serket