Key to US Neivamyrmex

Key to the workers & queens of US Neivamyrmex 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 The published key has subsequently been modified by Gordon Snelling and this key reflects these new unpublished changes.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

Eye present as a distinct convex facet . . . . . 2
Eye absent (pigmented eye-spot may be present) . . . . . 14

2

return to couplet #1

Suture between promesonotum and mesepisternum incomplete or absent . . . . . 3
Suture present and complete between promesonotum and mesepisternum . . . . . 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 . . . . . 4
Concave portion of preoccipital margin as wide as or wider than greatest width of pronotum; vertex strongly developed dorsolaterally, angulate or not . . . . . 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

Head of Neivamyrmex melanocephalus worker

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; 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; color uniformly reddish . . . . . Neivamyrmex graciellae

6

return to couplet #3

Petiole node in dorsal view less than 1.2 x longer than broad . . . . . 7
Petiole node in dorsal view at least 1.2 x longer than broad . . . . . 10

7

return to couplet #6

Head and body dull, coarsely granulopunctate . . . . . Neivamyrmex rugulosus

Head of Neivamyrmex rugulosus worker

Profile of Neivamyrmex rugulosus worker

Head and body smooth and shiny . . . . . 8

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)

Head of Neivamyrmex carolinensis worker

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; 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; 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

Head of Neivamyrmex opacithorax worker

Profile of Neivamyrmex opacithorax worker

12

return to couplet #11

Dorsal face of propodeum distinctly depressed below level of mesonotum; metafemur 6.4 x longer than greatest thickness . . . . . Neivamyrmex nigrescens (part)

Head of Neivamyrmex nigrescens worker

Profile of Neivamyrmex nigrescens worker

Dorsal face of propodeum not distinctly depressed; metafemur 6.2 x longer than greatest thickness . . . . . Neivamyrmex californicus

Head of Neivamyrmex californicus worker

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) . . . . . 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 . . . . . Neivamyrmex nigrescens (part)

Head of Neivamyrmex nigrescens worker

Profile of Neivamyrmex nigrescens worker

14

return to couplet #1

Petiole with anteroventral tooth . . . . . 15
Petiole without anteroventral tooth . . . . . 16

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 . . . . . Neivamyrmex swainsonii

Head of Neivamyrmex swainsonii worker

Profile of Neivamyrmex swainsonii worker

Petiole tooth small, lacking posteriorly directed spine; hind femur very short and robust, 3.4 x longer than thick; subantennal lamella distinct . . . . . Neivamyrmex ndeh

16

return to couplet #14

Basal (innermost) mandibular tooth not conspicuously enlarged relative to remaining teeth . . . . . 17
Basal mandibular tooth greatly enlarged relative to remaining teeth . . . . . 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 . . . . . 18
Petiole node distinctly longer than broad . . . . . 19

18

return to couplet #17

Broad lamella present below antennal fossa; head shiny between scattered distinct punctures . . . . . Neivamyrmex leonardi

Head of Neivamyrmex leonardi worker

Profile of Neivamyrmex leonardi worker

Without lamella below antennal fossa; 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 . . . . . 20
Antennal scape long and slender (about 3 x as long as broad), gradually tapered basad . . . . . Neivamyrmex nyensis