Key to Nomamyrmex workers

This worker key is based on: [[Media:Watkins 1977a.pdf|Watkins, J. F., II. 1977a. The species and subspecies of Nomamyrmex (Dorylinae: Formicidae). Journal of the Kansas Entomological Society. 50:203-214. PDF]]

Caution: A few workers of N. esenbecki s. str. and N. esenbecki crassicornis may have slightly concave mesonotal keels -usually not all workers in a series. These variants make couplet 2 of this key difficult; however, these workers can be distinguished on the basis of the geographical range given in couplet 2. The shape of the postpetiole of esenbecki s. str. ( c.f., couplet 4.a.), and the coloration of crassicornis ( c.f., couplet 4.b.) will also help distinguish these variants.

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Nomamyrmex

1

 * Postoccipital sulcus absent (Fig. 1); dorsum of petiole without longitudinal rugae . . . . . Nomamyrmex hartigii


 * Postoccipi tal sulcus present (Fig. 2-5); dorsum of petiole with longitudinal rugae ( esenbecki) . . . . . 2

2
return to couplet #1
 * Transversely keeled posterior margin of mesonotum slightly to moderately concave in middle (dorsal view, Fig. 4, 5); Costa Rica north to Austin, Texas . . . . . 3


 * Transversely keeled posterior margin of mesonotum usually straight or slightly convex in middle (dorsal view, Fig. 2, 3); Costa Rica south to Argentina . . . . . Nomamyrmex esenbeckii

3
return to couplet #2
 * Entire dorsum of propodeum with prominent longitudinal rugae, several of which extend almost to the posterior edge (dorsal view, Fig. 4); south Texas, northeast and south Mexico south to Costa Rica . . . . . Nomamyrmex esenbeckii wilsoni


 * Prominent longitudinal rugae confined to anterior half or two-thirds of dorsum of propodeum and usually do not extend to its posterior edge (dorsal view, Fig. 5); Mexico; west of Sierra Madre Occidental and extending southeastward along the Balsas River Valley . . . . . Nomamyrmex esenbeckii mordax