Key to the Anochetus Species of Asia, Melanesia and the Pacific Region

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This worker key is based on: Brown, W. L., Jr. 1978. Contributions toward a reclassification of the Formicidae. Part VI. Ponerinae, tribe Ponerini, subtribe Odontomachiti. Section B. Genus Anochetus and bibliography. Studia Entomologica. 20:549-638. The key also includes an update to the rugosus group given by: Satria, R., Viet, B.T., Eguchi, K. 2017. New synonymy and redescription of Anochetus mixtus Radchenko, 1993, and distinction from the other members of the Anochetus rugosus group (Hymenoptera: Formicidae: Ponerinae). Asian Myrmecology 9: e009006 (DOI 10.20362/am.009006).

This key is slightly outdated but is the best available for the genus.

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1

  • Mesial edge of mandible for much of its length with a single margin bearing 1 or 2 prominent teeth near midlength, or a close series of coarse dentlcles or teeth on apical half or more . . . . . 2
  • Mesial edge of mandible with 2 margins up to preapical tooth or angle: dorsal margin edentate (except for the single preapical tooth or angle, when this is present); ventral margin denticulate, crenulate, or smooth . . . . . 8

2

return to couplet #1

  • Mandible with 2 large submedian teeth on mesial margin, the distal tooth larger than the proximal (Sri Lanka) . . . . . Anochetus nietneri
  • Mandible with a single large submedian tooth (New Guinea) . . . . . 3
  • Mandible with a close series of 4 or more teeth along the mesial edge . . . . . 4

3

return to couplet #2

  • Striation of vertex reaching nuchal carina; central part of pronotum striate or rugulose, though the sculpture may sometimes be weak and nearly smooth in the anterior part of the disc; free corners of petiolar node rounded to sub-rectangular (Papua New Guinea) . . . . . Anochetus fricatus
Head of Anochetus fricatus worker
Profile of Anochetus fricatus worker
  • Striation of vertex separated from nuchal carina by a smooth, shining strip; disc of pronotum completely smooth and shining in the middle (except for small, scattered punctures); free corners of petiolar node produced as acute teeth (NE New Guinea) . . . . . Anochetus chirichinii
Head of Anochetus chirichinii worker
Profile of Anochetus chirichinii worker

4

return to couplet #2

  • Apex of petiole produced as a tooth or spine . . . . . 5
  • Apex of petiole narrowly rounded, not toothed . . . . . 6

5

return to couplet #4

Head of Anochetus gladiator worker
Profile of Anochetus gladiator worker
Head of Anochetus variegatus worker
Profile of Anochetus variegatus worker

6

return to couplet #4

6b

return to couplet #6

  • Dorsum of head in full-face view largely smooth and shiny, but frons distinctly striate obliquely and longitudinally; mesopleuron smooth and shiny; petiolar node with its basal half weakly striate . . . . . Anochetus mixtus
Satria viet et al-2017-A.jpg
Satria viet et al-2017-5 B.jpg
  • Dorsum of head in full-face view largely striated (striation extending to nuchal carina); anterior third of mesopleuron finely sculptured; petiolar node largely coarsely rugose . . . . . Anochetus rugosus
Head of Anochetus rugosus worker
Profile of Anochetus rugosus worker

7

return to couplet #6

  • Mandibles longer (MI>60); when head is seen in perfect full-face view, antennal scape surpassing posterior borders of occipital lobes by distinctly more than length of first funicular segment; head narrower (CI<90) . . . . . Anochetus princeps
Head of Anochetus princeps worker
Profile of Anochetus princeps worker
  • Mandibles shorter (MI<60); when head is seen in perfect full-face view, antennal scape surpassing posterior borders of occipital lobes at most by length of first funicular segment; head wider (CI 90 or more) . . . . . Anochetus muzziolii
Head of Anochetus muzziolii worker
Profile of Anochetus muzziolii worker

8

return to couplet #1

  • Intercalary tooth of mandibular apex small (sometimes worn to an indistinct tubercle, or even missing completely), rising from the dorsal side of the ventral apical tooth well beyond its mid length (measuring length from crotch with dorsal apical tooth) . . . . . (risii group) . . . . . 9
  • Intercalary tooth present; (center of its base) arising from near the base of the ventral apical tooth, or from near its midlength . . . . . 15

9

return to couplet #8

  • Pronotum smooth and shining over at least the large central part of its disc . . . . . 11

10

return to couplet #9

  • Size large, combined length of head and closed mandibles (HL + ML) > 2.5 mm; frontal striation spread over a wide area of the central vertex (Malaya) . . . . . Anochetus tua
Head of Anochetus tua worker
Profile of Anochetus tua worker
  • Size smaller, HL + ML < 2.2 mm; frontal striation confined to the space between frontal carinae (Luzon) . . . . . Anochetus incultus
Head of Anochetus incultus worker
Profile of Anochetus incultus worker

11

return to couplet #9

  • Very slender, elongate, CI < 83; petiole of particular form; perhaps 2 different species included (Borneo, Malaya) . . . . . Anochetus agilis
Head of Anochetus agilis worker
Profile of Anochetus agilis worker

12

return to couplet #11

  • Petiolar apex tapered gradually into a slender, spiniform tip (NE New Guinea) . . . . . Anochetus peracer
Head of Anochetus peracer worker
Profile of Anochetus peracer worker
  • Petiolar apex narrowly rounded or nipple-like, not spiniform . . . . . 13

13

return to couplet #12

  • Center of vertex extensively striate, the striation extending to within 0.2 mm of the nuchal carina (Malaya: Trengganu) . . . . . Anochetus strigatellus
Head of Anochetus strigatellus worker
Profile of Anochetus strigatellus worker
  • Frontal striation obsolete or restricted to, or nearly to, space between frontal carinae . . . . . 14

14

return to couplet #13

  • Mandibles long (ML > 1 .0 mm; MI > 68); worker eye L > 0.25 mm (SE China, Vietnam, Java) . . . . . Anochetus risii
Head of Anochetus risii worker
Profile of Anochetus risii worker
  • Mandibles of medium length (ML 0.70-0.90 mm; MI 57-63); worker eye L 0.16-0.21 mm (Java, Borneo, Philippines. . . . . Anochetus modicus
Head of Anochetus modicus worker
Profile of Anochetus modicus worker
  • Mandibles short (ML < 0.70 mm; MI about 50) ; worker eye L 0.13-0.14 mm (Mindanao) . . . . . Anochetus brevis
Head of Anochetus brevis worker
Profile of Anochetus brevis worker

15

return to couplet #8

  • As seen from front view, petiolar node tapered to a bluntly pointed (narrowly rounded or even nipple-like) apex (Melanesia and Philippines) . . . . . cato group . . . . . 16
  • Petiolar node as seen from front view with summit broadly rounded, transverse or concave . . . . . 18

16

return to couplet #15

  • Frontal striation nearly confined to space between frontal carinae, and not or only slightly extending posteriad beyond the level of the compound eyes . . . . . isolatus superspecies . . . . . 17
  • Frontal striation extending over a wide area of central vertex and reaching halfway or more of the distance between level of eyes and postero­median excision of head (N. Guinea, Bismarck Arch., Solomon Is.) . . . . . Anochetus cato
Head of Anochetus cato worker
Profile of Anochetus cato worker

17

return to couplet #16

  • Body color dark reddish-brown to yellowish brown (in callows?); HL + ML rarely if ever > 3.0 mm (Melanesia, Philippines) . . . . . Anochetus isolatus
Head of Anochetus isolatus worker
Profile of Anochetus isolatus worker
  • Head, trunk and node piceous; gaster and appendages reddish-brown; HL + ML slightly > 3.0 mm (Waigeo I., W. Irian; doubtfully distinct from isolatus) . . . . . Anochetus seminiger
Head of Anochetus seminiger worker
Profile of Anochetus seminiger worker
  • Head dark brown or piceous; rest of body light ferruginous to ferruginous yellow; propodeal costulae partly effaced, the surface here smooth and shining (Caroline Is.: Yap) . . . . . Anochetus splendidulus

18

return to couplet #15

  • Pronotal disc (at least a broad central field) and all of first gastric tergum smooth and shining when clean, with at most fine, spaced punctures . . . . . 19
  • Pronotal disc coarsely striate or punctate-rugulosej smooth interspaces, if any narrow and usually coarsely punctate; first gastric tergum rugulose, .striate or smooth, with or without coarse punctures . . . . . 25

19

return to couplet #18

  • Modest- or small-sized, lightly pigmented species with reduced eyes: comp0und eye L < 0.15 mm. their greatest diameter < maximum W of a mandible . . . . . 20
  • Larger species with large eyes: eye L > 0.25 mm and > maximum W of a mandible . . . . . 24

20

return to couplet #19

  • Propodeal angles produced as a pair of short teeth or tubercles . . . . . 21
  • Propodeal angles rounded. Unarmed; trunk with sculpture effaced smooth and shining, except for the delicately cross-striate propodeal declivity (W. Iran) . . . . . Anochetus evansi
Head of Anochetus evansi worker
Profile of Anochetus evansi worker

21

return to couplet #20

22

return to couplet #21

  • Mesonotal disc > twice as wide as long; mesonotal suture deeply impressed (Malaya: Perak) . . . . . Anochetus myops
Head of Anochetus myops worker
Profile of Anochetus myops worker
  • Mesonotal disc not more than twice as wide as long; meso-metanotal suture distinct .. but not deeply impressed (Sri Lanka) . . . . . Anochetus longifossatus
Profile of Anochetus longifossatus worker

23

return to couplet #21

  • Tiny species: HL + ML < 1 .25 mm; mesonotal disc > twice as wide as long (S India) . . . . . Anochetus pupulatus
Head of Anochetus pupulatus worker
Profile of Anochetus pupulatus worker
  • Slightly larger species: HL + ML of holotype about 1.5 mm; mesonotal disc not > twice as wide as long (Taiwan) . . . . . Anochetus subcoecus

24

return to couplet #19

  • Petiolar node axially compressed above; anterior slope concave, and summit rather bluntly rounded as seen from the side, but strongly transverse aa seen from above; body with very numerous short, fine, erect hairs; appressed pubescence scarcely developed on head, trunk, petiole and gaster; in full-face view of head, antennal sea pes surpass posterior borders of (occipital lobes by at least an apical scape width (S India: Madras State) . . . . . Anochetus rufus
Head of Anochetus rufus worker
Profile of Anochetus rufus worker
  • Petiolar node thick, erect, barrel-shaped; anterior slope convex, summit broadly rounded in both directions and only slightly broader than long; body with few or no erect hairs, except for those on apex and underside of gaster (0-9 standing hairs on trunk and first gastric tergum), but with abundant and conspicuous appressed pubescence; when head is viewed full-face, antennal scapes do not reach, or at least do not distinctly surpass, posterior borders of occipital lobes (W peninsular India; see also key to species of Africa, etc.) . . . . . Anochetus sedilloti
Head of Anochetus sedilloti worker
Profile of Anochetus sedilloti worker

25

return to couplet #18

  • Petiolar node as seen from the side thin, tapered to a very narrowly rounded, or even sharp, apex; scale-like part near its base not more than 0.20 mm long . . . . . graeffei group . . . . . 26
  • Petiolar node as seen from the side thick, with broadly rounded summit, and L > 0.25 mm near base of erect part of node . . . . . orientalis group . . . . . 27

26

return to couplet #25

  • HL + ML < 1.75 mm; eye L maximum 0.20 mm, usually much less (see key to Australian species; India to Melanesia, N & E Australia and S Polynesia) . . . . . Anochetus graeffei
Head of Anochetus graeffei worker
Profile of Anochetus graeffei worker
  • HL + ML < 1.75 mm; eye L > 0.20 mm; most of vertex smooth and shining, the frontal striation extending only a short distance beyond the level 01 the eyes (Sri Lanka) . . . . . Anochetus yerburyi
Head of Anochetus yerburyi worker
Profile of Anochetus yerburyi worker
  • HL + ML 1 .75 mm or more; eye L 0.20 mm or more; frontal striation reaching all the way to nuchal Carina (java), or most of the way (Sikkim, Hainan I.) . . . . . . . . . . . . . . problem samples: <large graeffei>, etc.

27

return to couplet #25

  • First gastric tergum densely and more or less opaquely sculptured over at least the anterior hall . . . . . 28
  • First gastric tergum smooth and shining, with only scattered, fine piligerous punctures (Sri Lanka, India) . . . . . Anochetus madaraszi
Head of Anochetus madaraszi worker
Profile of Anochetus madaraszi worker

28

return to couplet #27

  • Anterodorsal margin of petiolar node slightly produced anteriad, overhanging the anterior slope, which tends to be concave, trunk red; first gastric tergum black or piceous, coarsely punctate-striate and opaque to near posterior border (SW India) . . . . . Anochetus kanariensis
Head of Anochetus kanariensis worker
Profile of Anochetus kanariensis worker
  • Anterodorsal margin of petiolar node broadly rounded, like posterodorsal margin; anterior slope of node convex or straight as seen from the side trunk, petiole and gaster piceous or blackish, often with bluish opalescence, the first gastric tergum with punctate-rugulose sculpture thinning to nearly smooth and shining on posterior half or third of the segment

-(S Vietnam) . . . . . Anochetus orientalis

Head of Anochetus orientalis worker
Profile of Anochetus orientalis worker

-(S India) . . . . . Anochetus obscurior

Head of Anochetus obscurior worker
Profile of Anochetus obscurior worker

(The distinction between orientalis and obscurior, if any, is not clear, and the two may well be synonymous).