Key to US Neivamyrmex

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. [[Media:Snelling & Snelling 2007.pdf|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 The published key has subsequently been modified by Gordon Snelling and this key reflects these new unpublished changes.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 (Fig.31-47) . . . . . 3
 * Suture present and complete between promesonotum and mesepisternum (Fig. 30) . . . . . Neivamyrmex agilis

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

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


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


 * 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

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)


 * Cephalic punctures coarser, 1.2-1.7 PD apart in middle of frons; HF 4.4 x longer than thick . . . . . Neivamyrmex kiowapache (part)

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

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)


 * Dorsal face of propodeum not distinctly depressed (Fig. 31); metafemur 6.2 x longer than greatest thickness (Fig.. 85) . . . . . Neivamyrmex californicus

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


 * 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)

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 (Fig. 24) . . . . . Neivamyrmex swainsonii


 * 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

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


 * Without lamella below antennal fossa (Fig. 23); head shiny, with only scattered minute and indistinct piligerous punctures . . . . . Neivamyrmex pauxillus

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

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


 * Mesosomal dorsum smooth and shiny (Fig. 7) . . . . . Neivamyrmex microps


 * Mesosomal dorsum distinctly sculptured (Fig. 15), slightly shiny . . . . . Neivamyrmex wilsoni

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)


 * Cephalic punctures coarse 1.2-1.7 PD apart in middle of frons; HF 4.43x longer than thick . . . . . Neivamyrmex kiowapache (part)