Key to North American Pogonomyrmex

Modified from: Taber S.W. 1998. The World of the Harvester Ants. Texas A&M University Press. College Station.

The following key includes a genus name, Ephebomyrmex, that is currently a synonym of Pogonomyrmex.

Taber states that Ephebomyrmex and Pogonomyrmex are recognizable to tribe by their pectinate tibial spurs of the middle and/or hind legs. Pogonomyrmex are distinctive within the tribe by the presence of a psammophore. Ephebomyrmex have a poorly developed or lacking psammophore and a swollen clypeal plate. North American species can be identified to this group by a combination of: 1) lack of psammphore or only sparse setae present 2) dentary margin of mandible roughly tranverse 3) alitrunk profile almost continuous and roughly convex 4) cephalic sculpture coarsely rugo-reticulate 5) small size, 4-6 mm in length 6) docile behavior.

=I. Key to Pogonomyrmex=

1

 * thoracic setae dark (brownish black), propodeum unarmed (lacking spines or tubercles), clypeal apron strongly bidentate (Guatemala, Mexico) L = 5.0-5.5 mm . . . . . Pogonomyrmex guatemaltecus


 * thoracic setae clear or whitish . . . . . 2

2
return to couplet #1
 * venter of petiolar peduncle (near area that is or would be occupied by the ventral process) with one or more distinct setae (barbatus species complex) . . . . . 3


 * venter of petiolar peduncle (near area that is or would be occupied by the ventral process) without distinct seta(e) . . . . . 11

3
return to couplet #2
 * occipital corners with conspicuous rugae or striae . . . . . 4


 * occipital corners without conspicuous rugae or striae (smooth and shining) . . . . . 7

4
return to couplet #3
 * rugae of thoracic dorsum with conspicuous reticulation, cephalic and thoracic rugae coarse, widely spaced, head and/or thorax usually blackish or dark brown (U.S., Mexico) L = 7.0-9.5 mm . . . . . Pogonomyrmex rugosus


 * rugae of thoracic dorsum without conspicuous reticulation, color red or brownish red, but not blackish . . . . . 5

=II. Key to Ephebomyrmex=

1E

 * dorsum of basal segment of gaster with longitudinal rugae or striae . . . . . 2E


 * dorsum of basal segment of gaster without longitudinal rugae or striae . . . . . 5E

2E
return to couplet #1E
 * dorsum of basal segment of gaster entirely or mostly covered by rugae or striations (Colombia, Guyana) L = 7.6-9.0 mm . . . . . Ephebomyrmex mayri (= Pogonomyrmex mayri)


 * rugae or striae of dorsum of basal segment of gaster confined to basal half of segment, sometimes found only near insertion of postpetiole . . . . . 3E

3E
return to couplet #2E
 * anterior margin of clypeus convex, with small median triangular tooth (Venezuela) L = 5.0 mm . . . . . Ephebomyrmex abdominalis (= Pogonomyrmex abdominalis)


 * anterior margin of clypeus slightly excised or almost straight, but not broadly convex, margin without a small median triangular tooth . . . . . 4E

4E
return to couplet #3E
 * petiole and postpetiole not massive (much of South America) L = 4.0-5.0 mm. . . . . Ephebomyrmex naegelii (= Pogonomyrmex naegelii)


 * petiole and postpetiole massive (southern South America) L = 4.0-4.5 mm. . . . . Ephebomyrmex abdominalis (= Pogonomyrmex abdominalis)

5E
return to couplet #1E
 * maxillary palps with 5 segments, labial palps with 4 segments . . . . . 6E


 * b. maxillary palps with 4 segments, labial palps with 3 segments . . . . . 8E

6E
return to couplet #5E
 * head and alitrunk yellow or reddish, but not black (Argentina, Chile) L = 4.4-4.8 mm . . . . . Ephebomyrmex odoratus (= Pogonomyrmex odoratus)


 * head and alitrunk black or blackish . . . . . 7E

7E
return to couplet #6E
 * occiput and much of thoracic dorsum smooth, shining, few if any reticulations present, same for dorsum of petiolar node (Argentina, Chile) L = 4.5-5.0 mm . . . . . Ephebomyrmex laevigatus (= Pogonomyrmex laevigatus)


 * occiput with prominent reticulations and areolations, same for dorsum of thorax and petiolar node (Argentina, Chile) L = 4.6-6.0 mm . . . . . Ephebomyrmex angustus (= Pogonomyrmex angustus)

8E
return to couplet #5E
 * alitrunk in profile with distinct mesopropodeal depression, so that profile is not broadly convex (South America) . . . . . 9E


 * alitrunk in profile without distinct mesopropodeal depression, so that profile is broadly convex . . . . . 10E

9E
return to couplet #8E
 * head and alitrunk yellow, orange, or red, but not black (southern South America) L = 6.2-9.4 mm (worker), L = 12.0 mm (ergatogyne) . . . . . Ephebomyrmex cunicularius (= Pogonomyrmex cunicularius)


 * head and alitrunk black or blackish red (Argentina) L = 5.0-7.0 mm . . . . . Ephebomyrmex brevibarbis (= Pogonomyrmex brevibarbis)

10E
return to couplet #8E
 * anterior margin of clypeus broadly convex, head and alitrunk blackish or blackish red, setae of dorsum of basal segment of gaster erect or semierect and black (Haiti) . . . . . 11E


 * anterior margin of clypeus excised or straight, but not broadly convex, head and ali trunk yellow, red, or reddish brown, but never blackish (not Haiti) . . . . . 12E

11E
return to couplet #10E
 * petiolar node in dorsal view fan-shaped or shaped like baseball catcher's mitt (rugae present but rather sparse) (Haiti) L = 5.0-5.5 mm . . . . . Ephebomyrmex saucius (= Pogonomyrmex saucius)


 * petiolar node in dorsal view miter-shaped (node covered with coarse rugae) (Haiti) L = 3.5-4.5 mm . . . . . Ephebomyrmex schmitti (= Pogonomyrmex schmitti)

12E
return to couplet #10E
 * lateral clypeal projections prominent . . . . . 13E


 * lateral clypeal projections absent or very weak . . . . . 14E

13E
return to couplet #12E
 * propodeal spines absent, dorsum of petiolar node with little or no rugae, the surface almost smooth (Baja California) L = 3.5 mm . . . . . Ephebomyrmex laevinodis (= Pogonomyrmex laevinodis)


 * propodeal spines present, dorsum of petiolar node with conspicuous rugae (U.S., Mexico) L = 4.0-4.8 mm . . . . . Ephebomyrmex imberbiculus (= Pogonomyrmex imberbiculus)

14E
return to couplet #12
 * dorsum of basal segment of gaster with fine and appressed setae (lying flat or nearly so against the surface), dorsum of segment smooth and shining (not shagreened) (Argentina, Paraguay) L = 5.0 mm . . . . . Ephebomyrmex tenuipubens (= Pogonomyrmex tenuipubens)


 * setae on dorsum of basal segment of gaster erect or suberect (not appressed), dorsum of gaster at least lightly shagreened (U.S., Mexico) L = 3.5-4.0 mm . . . . . Ephebomyrmex pima (= Pogonomyrmex pima)