Key to US Neivamyrmex

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Key to the workers & queens of US Nievamyrmex species.

This key is based on: Snelling, G. C.; Snelling, R. R. 2007. New synonymy, new species, new keys to Neivamyrmex army ants of the United States. Memoirs of the American Entomological Institute 80:459-550. PDF. The published key has subsequently been modified by Gordon Snelling and this key reflects these new unpublished changes.

List of US Neivamyrmex species.

Neivamyrmex genus page

1

2

return to couplet #1

  • Suture between promesonotum and mesepisternum incomplete or absent (Fig.31-47) . . . . . 3
  • Suture present and complete between promesonotum and mesepisternum (Fig. 30) . . . . . Neivamyrmex agilis
Head of Neivamyrmex agilis worker
Profile of Neivamyrmex agilis worker

3

return to couplet #2

  • Concave portion of preoccipital margin not distinctly wider than greatest width of pronotum dorsal view) and strongly tapered, neck-like in appearance and vertex without prominent dorsolateral angles (Figs. 12a-b, 27) . . . . . 4
  • Concave portion of preoccipital margin as wide as or wider than greatest width of pronotum; vertex strongly developed dorsolaterally, angulate or not (Figs. 26, 28, 29) . . . . . 6

4

return to couplet #3

  • Subpetiolar process a prominent posteriorly directed spine; color variable black to brown or bicolored . . . . . 5
  • Subpetiolar process absent or present as a small anteriorly directed tooth; usually bicolored, red and black, but if all black, then mesonotum distinctly granulose . . . . . Neivamyrmex melanocephalus
Profile of Neivamyrmex melanocephalus worker

5

return to couplet #4

  • Mesonotum strongly convex in profile and posterior face of propodeum about as long as dorsal face (Fig. 43); color uniformly brownish to blackish . . . . . Neivamyrmex pilosus
Head of Neivamyrmex pilosus worker
Profile of Neivamyrmex pilosus worker
  • Mesonotum weakly convex in profile and posterior face of propodeum distinctly shorter than dorsal face (Fig. 34); color uniformly reddish . . . . . Neivamyrmex graciellae

6

return to couplet #3

  • Petiole node in dorsal view less than 1.2 x longer than broad (Figs. 62, 64, 65) . . . . . 7
  • Petiole node in dorsal view at least 1.2 x longer than broad (Figs. 61, 67) . . . . . 10

7

return to couplet #6

Head of Neivamyrmex rugulosus worker
Profile of Neivamyrmex rugulosus worker

8

return to couplet #7

  • Dorsal and lateral surfaces of petiole and postpetiole smooth and shiny, coarse punctures may be present but scattered; dorsolateral corners of head weakly developed, slightly rounded . . . . . 9
  • Dorsal and lateral surfaces of petiole and postpetiole strongly granulose; dorsolateral corners of head well developed and angulate . . . . . Neivamyrmex harrisii
Head of Neivamyrmex harrisii worker
Profile of Neivamyrmex harrisii worker

9

return to couplet #8

  • Cephalic punctures in middle of frons fine, separated by 2 PD or more; HF 5.15x longer than thick . . . . . Neivamyrmex carolinensis (part)
Profile of Neivamyrmex carolinensis worker
  • Cephalic punctures coarser, 1.2-1.7 PD apart in middle of frons; HF 4.4 x longer than thick . . . . . Neivamyrmex kiowapache (part)
Head of Neivamyrmex kiowapache worker
Profile of Neivamyrmex kiowapache worker

10

return to couplet #6

  • Head smooth and shiny between scattered fine piligerous punctures . . . . . 11
  • Head distinctly sculptured and roughened, often appearing granulopunctate . . . . . 13

11

return to couplet #10

  • Inner basal margin of mandible evenly curved into masticatory margin, without tooth or sharp angle at juncture (Fig. 17); pronotal sculpture variable, but side of pronotum usually at least weakly reticulate-punctate rather than exhibiting a smooth shiny surface that contrasts with the sculptured mesosoma dorsum . . . . . 12
  • Inner basal margin of mandible straight, with distinct tooth or sharp angle at juncture with masticatory margin (Figs. 19); side of pronotum usually smooth and shiny, and contrasting with the rugulose-punctate sculpture that covers at least part of the mesosomal dorsum . . . . . Neivamyrmex opacithorax
Profile of Neivamyrmex opacithorax worker

12

return to couplet #11

  • Dorsal face of propodeum distinctly depressed below level of mesonotum (Fig. 40); metafemur 6.4 x longer than greatest thickness (Fig.89) . . . . . Neivamyrmex nigrescens (part)
Head of Neivamyrmex nigrescens worker
Profile of Neivamyrmex nigrescens worker
  • Dorsal face of propodeum not distinctly depressed (Fig. 31); metafemur 6.2 x longer than greatest thickness (Fig.. 85) . . . . . Neivamyrmex californicus
Profile of Neivamyrmex californicus worker

13

return to couplet #10

  • In lateral view declivitous face of propodeum slightly concave and forming a subanagular junction with the dorsal (basal) surface; Petiole relatively short and high; Posterior face of propodeum slightly concave in profile and distinctly angulate at juncture with dorsal face angulate (angle may be indistinct in small specimens) (Fig.46) . . . . . Neivamyrmex texanus
Head of Neivamyrmex texanus worker
Profile of Neivamyrmex texanus worker
  • Declivitous face of propodeum more or less straight in lateral view and forming a rounded angle with the dorsal(basal) surface*; petiole height lower; Posterior face of propodeum not concave in profile and rounded into juncture with dorsal face (Fig. 40) . . . . . Neivamyrmex nigrescens (part)
Head of Neivamyrmex nigrescens worker
Profile of Neivamyrmex nigrescens worker

14

return to couplet #1

15

return to couplet #14

  • Petiole tooth well developed and with posteriorly directed spine; hind femur at least 4 x longer than thick; subantennal lamella absent or poorly developed (Fig. 24) . . . . . Neivamyrmex swainsonii
Head of Neivamyrmex swainsonii worker
Profile of Neivamyrmex swainsonii worker
  • Petiole tooth small, lacking posteriorly directed spine (Fig. 74); hind femur very short and robust, 3.4 x longer than thick (Fig. 87); subantennal lamella distinct (Fig. 4) . . . . . Neivamyrmex ndeh

16

return to couplet #14

  • Basal (innermost) mandibular tooth not conspicuously enlarged relative to remaining teeth (Figs. 22-24) . . . . . 17
  • Basal mandibular tooth greatly enlarged relative to remaining teeth (Fig. 21) . . . . . Neivamyrmex moseri
Head of Neivamyrmex moseri worker
Profile of Neivamyrmex moseri worker

17

return to couplet #16

  • Petiole node no longer than broad or only slightly so (Figs.9) . . . . . 18
  • Petiole node distinctly longer than broad (Figs. 65, 66, 68, 71) . . . . . 19

18

return to couplet #17

  • Broad lamella present below antennal fossa (Fig. 25); head shiny between scattered distinct punctures . . . . . Neivamyrmex leonardi
Head of Neivamyrmex leonardi worker
Profile of Neivamyrmex leonardi worker
  • Without lamella below antennal fossa (Fig. 23); head shiny, with only scattered minute and indistinct piligerous punctures . . . . . Neivamyrmex pauxillus
Head of Neivamyrmex pauxillus worker
Profile of Neivamyrmex pauxillus worker

19

return to couplet #17

  • Antennal scape short and stout, not evenly tapered basad (Fig. 6, 7, 15) . . . . . 20
  • Antennal scape long and slender (about 3 x as long as broad) (Fig. 10), gradually tapered basad . . . . . Neivamyrmex nyensis
Head of Neivamyrmex nyensis worker
Profile of Neivamyrmex nyensis worker

20

return to couplet #19

  • Subantennal lamella well developed (Fig. 7, 15) . . . . . 21
  • Subanatennal lamella absent or greatly reduced (Fig. 3, 6) . . . . . 22

21

return to couplet #20

Head of Neivamyrmex microps worker
Profile of Neivamyrmex microps worker
Head of Neivamyrmex wilsoni worker
Profile of Neivamyrmex wilsoni worker

22

return to couplet #20

  • Cephalic punctures in middle of frons fine, separated by 2 PD or more; HF 5.15x longer than thick . . . . . Neivamyrmex carolinensis (part)
Profile of Neivamyrmex carolinensis worker
  • Cephalic punctures coarse 1.2-1.7 PD apart in middle of frons; HF 4.43x longer than thick . . . . . Neivamyrmex kiowapache (part)
Head of Neivamyrmex kiowapache worker
Profile of Neivamyrmex kiowapache worker