Key to Ant Genera of the Navajo Reservation

This key to workers is based on

Ellison, A. M.; Gotelli, N. J.; Farnsworth, E. J.; Alpert, G. D. 2012. A field guide to the ants of New England . New Haven: Yale University Press, xv + 398 pp
Fisher, B. L.; Cover, S. P. 2007. Ants of North America. A guide to genera. Berkeley: University of California Press, xiv + 194 pp. [2007-09]
Mackay, W.P. & Mackay, E.E. 2002. The Ants of New Mexico: 400 pp. Edwin Mellen Press, Lewiston, N.Y.

At present 24 ant genera are known within the Navajo Reservation, as additional ant genera are discovered, they will be added to the key below. Each Navajo genus page links to a Navajo species level key for workers on the Navajo Reservation and each species page will then link to the AntWiki species page.

1

Petiole and postpetiole present (pedicel has two segments) . . . . . 2

Profile of Veromessor smithi worker

Profile of Pogonomyrmex imberbiculus worker

Profile of Temnothorax carinatus worker

Petiole present (pedicel has one segment), postpetiole absent or not well separated from remainder of gaster . . . . . 3

Profile of Hypoponera opacior worker

Profile of Formica neorufibarbis worker

Profile of Dorymyrmex insanus worker

2 (1)

Antennal sockets completely exposed in full-face view, not covered by frontal lobes. Antennal sockets positioned close to each other and inserted at the anterior margin of the head. Eyes absent or extremely small (Subfamily Ecitoninae) . . . . . Neivamyrmex (2 species)

Frontal view of Neivamyrmex nyensis worker

Frontal view of Neivamyrmex opacithorax worker

In full-face view antennal sockets covered at least in part by frontal lobes. Antennal sockets well separated and set back from the anterior margin of the head. Eyes present with several facets or more. (Subfamily Myrmicinae) . . . . . 5

Frontal view of Crematogaster larreae worker

Frontal view of Veromessor lobognathus worker

3 (1)

No postpetiole, petiole clearly separated from remainder of gaster; sting absent. . . . . . 4

Lateral view of Camponotus ocreatus worker

Lateral view of Formica aserva worker

Dorsal view of Liometopum luctuosum worker

Postpetiole with a slight separation from remainder of gaster; sting present; Subpetiolar process simple lobe, never with fenestra or paired posterolateral teeth. Anterior border of clypeus without teeth; mandible relatively small (Subfamily Ponerinae). . . . . Hypoponera opacior

Frontal view of Hypoponera opacior worker

Lateral view of Hypoponera opacior worker

Dorsal view of Hypoponera opacior worker

4 (3)

Acidopore absent, no ring of hairs at apex of gaster (Subfamily Dolichoderinae) . . . . . 15

Acidopore at apex of gaster round and usually surrounded by ring of hairs (Subfamily Formicinae) . . . . . 18

5 (2)

Antennae with 10 segments, last 2 segments forming a distinct club; propodeum without spines; either dimorphic species or very small monomorphic species . . . . . Solenopsis (2 species)

Frontal view of Solenopsis xyloni major

Lateral view of Solenopsis xyloni major

Dorsal view of Solenopsis xyloni worker

Antenna consisting of 11 segments . . . . . 6

Antenna consisting of 12 segments . . . . . 9

6 (5)

Postpetiole connected to dorsal surface of gaster; gaster, when seen from above, heart shaped with pointed apex; pronotum without spines or bumps . . . . . Crematogaster (3 species)

Lateral view of Crematogaster larreae worker

Lateral view of Crematogaster depilis worker

Dorsal view of Crematogaster navajoa worker

Postpetiole not connected to upper surface of gaster; gaster not heart shaped . . . . . 7

7 (6)

Eyes with short, erect hairs emerging from facets (use high magnification)(Found inside the nests of Formica ravida)...Formicoxenus hirticornis

Frontal view of Formicoxenus hirticornis worker

Lateral view of Formicoxenus hirticornis worker

Dorsal view of Formicoxenus hirticornis worker

Eyes lacking erect hairs..... 8

8 (7)

Mandible with six teeth. Clypeus not forming welt; frontal carinae do not extend to posterior border of head . . . . . Leptothorax (3 species)

Frontal view of Leptothorax crassipilis worker

Lateral view of Leptothorax crassipilis worker

Dorsal view of Leptothorax crassipilis worker

Mandible with five teeth. ...Temnothorax (9 species)

Frontal view of Temnothorax carinatus worker

Lateral view of Temnothorax carinatus worker

Dorsal view of Temnothorax carinatus worker

9 (5)

Middle and hind tibial spurs pectinate (with tiny hairs, difficult to see without at least 60x magnification) . . . . . 10

Middle and hind tibial spurs not pectinate . . . . . 11

10 (9)

Metanotal constriction (between mesonotum and propodeum) absent, propodeum often with spines or teeth, psammophore (long curved hairs on underside of head) usually present; common in arid ecosystems . . . . . Pogonomyrmex /(Key to 6 species)

Dorsal view of Pogonomyrmex maricopa worker

Lateral view of Pogonomyrmex imberbiculus worker

Lateral view of Pogonomyrmex rugosus worker

Metanotal constriction present between mesonotum and propodeum , propodeum always has spines; psammophore absent; common in pine forests and mountainous areas. . . . . . Myrmica / (5 species)

Dorsal view of Myrmica brevispinosa worker

Lateral view of Myrmica rugiventris worker

Lateral view of Myrmica tahoensis worker

11 (9)

Propodeum without spines; antennal club composed of 3 segments; usually small, shiny, black ants . . . . . Monomorium (2 species)

Frontal view of Monomorium cyaneum worker

Lateral view of Monomorium cyaneum worker

Dorsal view of Monomorium cyaneum worker

Propodeum with spines or teeth; antennal club configuration varies . . . . . 12

12 (11)

Psammophore present... Messor (2 species)

Frontal view of Veromessor lobognathus worker

Lateral view of Veromessor lobognathus worker

Dorsal view of Veromessor lobognathus worker

Psammophore absent; . . . . . 13

Lateral view of Aphaenogaster huachucana worker

Lateral view of Stenamma californicum worker

Lateral view of Pheidole hyatti worker

13 (12)

Workers dimorphic or polymorphic; major with head longer than gaster; petiole with long peduncle; scape of antenna of minor often extends past posterior border of head; mandible with 2 well defined teeth at apex; . . . . . Pheidole / (8 species)

Frontal view of Pheidole hyatti worker

Lateral view of Pheidole hyatti worker

Dorsal view of Pheidole hyatti worker

Monomorphic species; scape does not extend past posterior lateral border of head . . . . . 14

14 (13)

Clypeus usually with pair of longitudinal carinae; mesosoma thickened with little constriction between mesonotum and propodeum . . . . . Stenamma / (3 species)

Frontal view of Stenamma snellingi worker

Lateral view of Stenamma snellingi worker

Dorsal view of Stenamma snellingi worker

Clypeus without carinae or with more than 1 pair; mesosoma slender . . . . . Aphaenogaster (2 species)

Frontal view of Aphaenogaster huachucana worker

Lateral view of Aphaenogaster huachucana worker

Dorsal view of Aphaenogaster huachucana worker

15 (4)

Propodeum in form of cone; maxillary palps very long . . . . . Dorymyrmex (4 species)

Frontal view of Dorymyrmex bicolor worker

Lateral view of Dorymyrmex bicolor worker

Dorsal view of Dorymyrmex bicolor worker

Propodeum never in form of cone . . . . . 16

16 (15)

Node of petiole poorly developed; monomorphic ants, widely distributed in mesic areas . . . . . Tapinoma sessile

Frontal view of Tapinoma sessile worker

Lateral view of Tapinoma sessile worker

Dorsal view of Tapinoma sessile worker

Node of petiole obvious, although it may be small; common ants . . . . . 17

17 (16)

Workers polymorphic; mesosoma in profile without impression before posterior edge of propodeum; ocelli present at least in larger workers; gaster with gray pubescence; nests usually in oak trees or under stones in mountainous areas . . . . . Liometopum (2 species)

Frontal view of Liometopum apiculatum worker

Lateral view of Liometopum apiculatum worker

Dorsal view of Liometopum apiculatum worker

Erect hairs on clypeus long, extending to near tips of mandibles, when mandibles are shut; pronotum with at least I pair of long, erect hairs (may be missing in some specimens in nest series); Workers monomorphic; ocelli absent; nesting in soil most common in desert regions (also common in urban areas) . . . . . Forelius pruinosus

Frontal view of Forelius pruinosus worker

Lateral view of Forelius pruinosus worker

Dorsal view of Forelius pruinosus worker

18 (4)

Antenna with 9 segments; small, light colored, inconspicuous ants, not commonly collected . . . . . Brachymyrmex depilis

Frontal view of Brachymyrmex depilis worker

Lateral view of Brachymyrmex depilis worker

Dorsal view of Brachymyrmex depilis worker

Antenna with more than 9 segments; common ants . . . . . 19

19 (18)

Mandibles long, sickle shaped; red ants, not commonly collected . . . . . Polyergus mexicanus

Frontal view of Polyergus mexicanus worker

Lateral view of Polyergus mexicanus worker

Dorsal view of Polyergus mexicanus worker

Mandibles not long and sickle shaped, common ants . . . . . 20

20 (19)

Insertions of antennae located far from posterior border of clypeus; mesosoma convex (except for C. hyatti) in profile . . . . . Camponotus (6 species)

Frontal view of Camponotus laevissimus worker

Lateral view of Camponotus hyatti worker

Lateral view of Camponotus ocreatus worker

Insertions of antennae located near posterior border of clypeus; mesosoma not convex in profile . . . . . 21

Frontal view of Myrmecocystus mexicanus worker

Lateral view of Myrmecocystus mexicanus worker

Lateral view of Formica aserva worker

21 (20)

Maxillary palps very long, segment 4 as long as segments 5 and 6 combined; psammophore present . . . . . Myrmecocystus (6 species)

Frontal view of Myrmecocystus mendax worker

Lateral view of Myrmecocystus mendax worker

Maxillary palps shorter, segment 4 not unusually long; psammophore absent . . . . . 22

22 (21)

Frontal carinae prominent, lateral margins slightly reflected upward; ocelli often distinct; mostly large, polymorphic . . . . . Formica (17 species)

Frontal view of Formica densiventris worker

Lateral view of Formica densiventris worker

Dorsal view of Formica densiventris worker

Frontal carinae poorly marked, lateral margins flat; ocelli indistinct or absent; smaller monomorphic ants. Maxillary palps short and composed of 3 segments (subgenus Acanthomyops), maxillary palps longer and composed of 6 segments . . . . . Lasius (12 species)

Frontal view of Lasius fallax worker

Lateral view of Lasius fallax worker

Dorsal view of Lasius fallax worker