Key to Strumigenys of East Asia (as Pyramica)

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

Malasian-Oriental-East Palaearctic Pyramica

Bolton noted: Strumigenys formosa of Taiwan (p. 452), known only from queens, is omitted from the key. Its workers would be expected to key out around couplets 26-27.

This key is from a study that included the now synonymized genus Pyramica. Therefore there are two sets of keys for the Strumigenys species from this region: the key found below and a Key to Strumigenys of East Asia.

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 * Strumigenys

1

 * Antenna with 4 segments; first funicular segment not separated from the 2-segmented apical club. (India, Nepal, Thailand, Malaysia (West Malaysia), Singapore) . . . . . Strumigenys nepalensis


 * Antenna with 5 or 6 segments; first funicular segment separated from the 2-segmented apical club by one or two small segments . . . . . 2

2
return to couplet #1
 * Antenna with 5 segments; first funicular segment separated from the 2-segmented apical club by a single small segment. (Malaysia (West Malaysia)) . . . . . Strumigenys gyges


 * Antenna with 6 segments; first funicular segment separated from the 2-segmented club by two small segments . . . . . 3

3
return to couplet #2
 * With head in full-face view the leading edge of the scape with a row of conspicuous projecting curved hairs, of which one or more, distal to the subbasal bend, distinctly curves toward the base of the scape. These hairs may be spatulate, remiform, spoon-shaped or broadly clavate apically; basal stem of each hair (which may be short) erect or sub erect with respect to the long axis of the scape . . . . . 4


 * With head in full-face view the leading edge of the scape lacking projecting hairs that curve toward the base of the scape. Scape edge may have elongate simple straight projecting hairs present, or entirely apically directed short hairs that may be simple, narrowly to broadly spatulate, or spoon-shaped; in some species the leading edge may be hairless . . . . . 35

4
return to couplet #3
 * With head in full-face view the dorsolateral margin with a distinctly isolated, very conspicuous, laterally projecting apicoscrobal hair; apicoscrobal hair conspicuously differentiated from other pilosity on the margin, may be simple, clavate or flagellate . . . . . 5


 * With head in full-face view the dorsolateral margin without a distinctly isolated apicoscrobal hair that is conspicuously differentiated from other pilosity on the margin; either hair absent or duplicated by others on the margin . . . . . 23

5
return to couplet #4
 * Pronotal humeral hair absent. Dorsum of pronotum densely clothed with scale-like or stud-like broad hairs. Ventral margin of petiole peduncle without a longitudinal spongiform strip from base to level of node. Base of first gastral sternite without spongiform tissue. Standing stout hairs on first gastral tergite restricted to a single transverse row of four extremely close to the base. (Malaysia (Sarawak)) . . . . . Strumigenys clotho


 * Pronotal humeral hair present, may be simple, clavate, remiform or flagellate. Dorsum of pronotum lacking scale-like or stud-like broad hairs. Ventral margin of petiole peduncle with a continuous longitudinal spongiform strip from base to level of node, even if only narrowly so. Base of first gastral sternite with spongiform tissue. Standing hairs on first gastral tergite not restricted to a single transverse row close to the base . . . . . 6

6
return to couplet #5
 * Pronotal humeral hair long and flagellate; either freely projecting, or with its apical portion looped . . . . . 7


 * Pronotal humeral hair not flagellate; either simple and shallowly curved, or narrowly clavate, or remiform . . . . . 10

7
return to couplet #6
 * Cephalic dorsum with a transverse row of 4 standing hairs immediately in front of the occipital margin, but without a similar pair in front of the highest point of the vertex. Apicoscrobal hair not flagellate . . . . . 8


 * Cephalic dorsum with a transverse row of 4 standing hairs immediately in front of the occipital margin, and with a pair of similar standing hairs just in front of the highest point of the vertex. Apicoscrobal hair flagellate . . . . . 9

8
return to couplet #7
 * Eye minute, with only 1 or 2 very small ommatidia. Mesopleuron and metapleuron, and side of propodeum, smooth and shining. (Malaysia (West Malaysia)) . . . . . Strumigenys vescops


 * Eye larger, distinctly with more than 2 ommatidia. Mesopleuron smooth but metapleuron and side of propodeum reticulate-punctate. (Marquesas Is) . . . . . Strumigenys mumfordi

9
return to couplet #7
 * Mesonotum in profile with a single pair of erect long stout hairs, situated anteriorly on the sclerite. (Malaysia (West Malaysia, Sabah), Philippines (Luzon), Indonesia (Bali, Sumatra, Sulawesi, Kai Besar, Aru), Papua New Guinea, Solomon Is, Palau Is, also present in Australia) . . . . . Strumigenys karawajewi


 * Mesonotum in profile with two pairs of erect long stout hairs, the posterior pair usually distinctly the longer. (Bhutan, China, Burma, Thailand, Malaysia (West Malaysia, Sarawak, Sabah), Philippines (Luzon), Indonesia (Kalimantan, Bali, Java, Sumatra)) . . . . . Strumigenys dohertyi

10
return to couplet #6
 * Apical (masticatory) margin of mandible finely serrate, with distinctly more than 20 small to minute denticles crowded along the margin; basal 5-7 teeth not large and not the only ones clearly visible when the mandibles are fully closed . . . . . 11


 * Apical (masticatory) margin of mandible dentate, with 1 2 teeth and denticles in total on the margin; basal 5-7 teeth relatively large and the only ones clearly visible when the mandibles are fully closed . . . . . 12

11
return to couplet #10
 * First gastral tergite behind level of basigastral costulae (when clean) finely and densely coriaceous; the same sculpture also present on apical half of first gastral sternite. Disc of postpetiole not uniformly sharply reticulate-punctate. (Indonesia (Sulawesi)) . . . . . Strumigenys serraformis


 * First gastral tergite behind level of basigastral costulae (when clean), and first gastral sternite, glassy smooth and highly polished, without coriaceous sculpture. Disc of postpetiole very uniformly sharply reticulate-punctate. (Philippines (Luzon)) . . . . . Strumigenys serradens

12
return to couplet #10
 * With head in full-face view the outer margins of the mandibles shallowly concave behind the apical third; the mandibles relatively long, MI 35-36. Anterior face of petiole node in profile more or less continuing the line of the peduncle in a sinuous curve, the two not separated by a marked angle. (Indonesia (Sulawesi)) . . . . . Strumigenys rhea


 * With head in full-face view the outer margins of the mandibles evenly shallowly convex; the mandibles relatively short, MI 21-29. Anterior face of petiole node in profile separated from the line of the peduncle by a marked obtuse angle . . . . . 13

13
return to couplet #12
 * In dorsal view the disc of the postpetiole smooth and shining (when clean), without reticulate-punctate or punctate-rugulose sculpture, without trace of longitudinal costulae or at most with vestigial sculpture. If sculpture vestiges present then HW < 0.50 . . . . . 14


 * In dorsal view the disc of the postpetiole sculptured, either reticulate-punctate, punctate-rugulose, or finely densely and usually sharply longitudinally costulate across most or all of its surface. If sculpture partially effaced then HW 0.50 or greater . . . . . 20

14
return to couplet #13
 * Pronotal humeral hair elongate and gradually tapering to an acute apex. With waist segments in dorsal view the petiole node shining, similar to the disc of the postpetiole. SI ca 67, CI ca 75 . (Tahiti) . . . . . Strumigenys insula


 * Pronotal humeral hair stout, truncated-remiform or weakly clavate apically. With waist segments in dorsal view the petiole node reticulate-punctate, contrasting strongly with the smooth disc of the postpetiole. SI 50-60, CI 78-94 . . . . . 15

15
return to couplet #14
 * Side of pronotum obliquely costulate. Metapleuron and side of propodeum longitudinally costulate. Ventral spongiform strip of petiole reduced to a carina-like vestige beneath the peduncle. (Papua New Guinea) . . . . . Strumigenys tethys


 * Side of pronotum partially to entirely reticulate-punctate. Metapleuron and side of propodeum mostly smooth to entirely reticulate-punctate, never costulate. Ventral spongiform strip of petiole distinct beneath the peduncle . . . . . 16

16
return to couplet #15
 * Alitrunk in profile with dorsal outline evenly sloping downwards posteriorly, usually at an angle of about 45 0, from anterior mesonotum to propodeal tooth; without an impressed metanotal groove and without a change of slope between mesonotum and propodeum. Head broad, CI > 90. Alitrunk short and stocky, the pronotum broad; AL < 1.50 X maximum alitrunk height, AL about 1.70 X pw. (Papua New Guinea) . . . . . Strumigenys phasma


 * Alitrunk in profile with dorsal outline not evenly sloping downwards from anterior mesonotutn to propodeal tooth; either mesonotum and propodeum form separate convexities, or metanotal groove distinctly impressed, or with a marked change of slope between mesonotum and propodeum. Head narrower, CI 79-89. Alitrunk longer and narrower; AL > 1.50 X maximum alitrunk height, AL 1.80-2.00 X PW . . . . . 17

17
return to couplet #16
 * Mesonotal dorsum with a single pair of stout standing hairs . . . . . 18


 * Mesonotal dorsum with two pairs of stout standing hairs . . . . . 19

18
return to couplet #17
 * Disc of petiole node in dorsal view much broader than long, transversely rectangular. Postpetiole massively developed in dorsal view, its disc conspicuously twice broader than long and twice as broad as the petiole node. Dark brown to black species with MI 26-27. (Fiji Is) . . . . . Strumigenys trauma


 * Disc of petiole node in dorsal view at most only fractionally broader than long, not transversely rectangular. Postpetiole relatively small in dorsal view, its disc distinctly less than twice broader than long, less than twice as broad as the petiole node. Light reddish-brown species with MI 21-22. (Samoa) . . . . . Strumigenys epipola

19
return to couplet #17
 * In dorsal view sides of petiole and postpetiole not entirely margined with projecting spongiform tissue. Ventral spongiform lobe of postpetiole in profile smaller than the exposed area of the postpetiole disc. With alitrunk in profile the propodeal dorsal outline markedly convex behind the metanotal groove. Yellow to light yellowish brown species with MI 25-29. (Indonesia (Sulawesi), Papua New Guinea) . . . . . Strumigenys themis


 * In dorsal view sides of both petiole and postpetiole thickly margined with projecting spongiform tissue. Ventral spongiform lobe of postpetiole in profile distinctly larger than the exposed area of the postpetiole disc. With alitrunk in profile the propodeal dorsal outline approximately flat and sloping posteriorly behind the metanotal groove. Darker reddish brown species with MI 2 1 . (Indonesia (Sumatra)) . . . . . Strumigenys charybdis

20
return to couplet #13
 * Leading edge of scape in dorsal view with subbasal bend developed into a projecting triangular flattened tooth before its narrow basal section (longest hair on margin arises from apex of this tooth). Very large species with head very broad, HW > 0.90, CI 97-101. (Papua New Guinea) . . . . . Strumigenys dentiscapa


 * Leading edge of scape in dorsal view with subbasal bend broadly shallowly and evenly convex before its narrow basal section. Markedly smaller species with narrower heads, HW 0.50-0.62, CI 80-89 . . . . . 21

21
return to couplet #20
 * Sides of alitrunk entirely sharply reticulate-punctate, without smooth unsculptured areas. Dorsum of mesonotum with 3 (or rarely 4) pairs of stout standing hairs. (Malaysia (Sabah)) . . . . . Strumigenys theia


 * Sides of alitrunk not entirely reticulate-punctate, with smooth un sculptured areas on mesopleuron, metapleuron, or propodeum. Dorsum of mesonotum with 2 pairs of standing hairs . . . . . 22

22
return to couplet #21
 * With petiole in profile the dorsal length of the node, discounting the posterior collar, greater than the height of the anterior face of the node; petiole node in dorsal view usually longer than broad. With postpetiole in profile the ventral spongiform lobe at least equal in area to the exposed portion of the disc. (Malaysia (West Malaysia), Philippines (Luzon, Negros) . . . . . Strumigenys pedunculata


 * With petiole in profile the dorsal length of the node, discounting the posterior collar, subequal to the height of the anterior face of the node; petiole node in dorsal view broader than long. With postpetiole in profile the ventral spongiform lobe much smaller in area than the exposed portion of the disc. (Indonesia (Sulawesi, Seram), Papua New Guinea) . . . . . Strumigenys capitata

23
return to couplet #4
 * Mandibles elongate and narrow, linear; in full-face view and at full closure only their extreme apices engage. Leading edge of scape with a large, strongly prominent subbasal lobe . . . . . 24


 * Mandibles sub triangular to triangular, not linear; in full-face view and at full closure they engage for half or more of their exposed length. Leading edge of scape with a gradual subbasal curve or subbasal angle, without a large, strongly prominent subbasal lobe . . . . . 28

24
return to couplet #23
 * Mandible without preapical teeth. Pronotal dorsum covered with numerous large flat orbicular hairs. Cephalic dorsum without a transverse blunt ridge or crest across highest point of vertex. Dorsum of mandible not abruptly depressed near base where it passes beneath the anterior clypeal margin . . . . . 25


 * Mandible with 2 or more preapical teeth. Pronotal dorsum not covered with large orbicular hairs. Cephalic dorsum with a transverse blunt ridge or crest across highest point of vertex. Dorsum of mandible abruptly depressed near base where it passes beneath the anterior clypeal margin . . . . . 26

25
return to couplet #24
 * Dorsal surface of mandible without longitudinal rows of anteriorly directed spoon-shaped or scale-like hairs. The two pairs of hairs closest to the midline on the anterior clypeal margin short, narrowly spoon-shaped and curved or inclined toward the midline. Orbicular hairs on clypeus all of approximately the same size. (Japan, Taiwan) . . . . . Strumigenys hirashimai


 * Dorsal surface of mandible with two longitudinal rows of anteriorly directed spoon-shaped or scale-like hairs. The two pair of hairs closest to the midline on the anterior clypeal margin long and strap-like, directed anteriorly and curved slightly away from the midline. Orbicular hairs on clypeus much smaller centrally than near lateral and posterior margins. (China) . . . . . Strumigenys lachesis

26
return to couplet #24
 * Eyes absent. Cephalic dorsum without small orbicular hairs. (Nepal) . . . . . Strumigenys hemisobek


 * Eyes present but minute, of only 1 or 2 ommatidia. Cephalic dorsum with small orbicular hairs, at least immediately behind the clypeus . . . . . 27