Key to Megalomyrmex males of Central America

This key to males is based on: Boudinot, B.E. Sumnicht, T.P. and Adams, R.M.M. 2013. Central American ants of the genus Megalomyrmex Forel (Hymenoptera: Formicidae): six new species and keys to workers and males. Zootaxa 3732:1-82.

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 * Megalomyrmex
 * Key to Megalomyrmex workers of Central America

Male-based key to Central American species

Notes: Males of five Central American species remain unknown: Megalomyrmex longinoi, M. osadrifti, M. fungiraptor, M. nocarina, and M. reina. It is predicted that M. fungiraptor males will run to couplet 3 based on the conformity of male and female wing venation and the similarity of M. fungiraptor females to those of M. adamsae and M. symmetochus; it is also predicted that the undescribed drifti complex males will run to “M. megadrifti” in couplet 7.

1

 * Forewing crossvein 1m-cu present (fig. 43) . . . . . 2


 * Forewing crossvein 1m-cu absent (fig. 44) . . . . . 9

2
return to couplet #1
 * Dorsal face of mandible coarsely striate. Minimum distance between compound eye and lateral ocellus less than one lateral ocellus length (fig. 45) and/or scape length greater than that of antennomeres 2–4 . . . . . 3


 * Dorsal face of mandible mostly smooth. Minimum distance between compound eye and lateral ocellus greater than one lateral ocellus length (figs. 46 & 47) and scape length less than that of antennomeres 2–4 . . . . . 4

3
return to couplet #2
 * Setae on gastric tergum I coarse, stiff, somewhat dilute (fig. 48). Ventral face of petiole with two longitudinal carinulae flanking median longitudinal carinula. Panama . . . . . Megalomyrmex adamsae


 * Setae on gastric tergum I fine, flexuous, relatively dense (fig. 49). Ventral face of petiole with at least four carinulae flanking median carinula. Nicaragua to Panama . . . . . Megalomyrmex symmetochus

4
return to couplet #2
 * Occipital carina visible in full-face view (fig. 50) . . . . . 5


 * Occipital carina obscured by vertex in full-face view, well below level of ocellar region (fig. 51) . . . . . 6

5
return to couplet #4
 * Mesosoma robust. Mesoscutellum strongly bulging in profile view (fig. 52). Costa Rica to Venezuela . . . . . Megalomyrmex modestus


 * Mesosoma gracile. Mesoscutellum weakly bulging in profile view (fig. 53). Southern Mexico to northern Argentina . . . . . Megalomyrmex silvestrii

6
return to couplet #4
 * Masticatory margin of mandible with three or four large, widely-spaced teeth (fig. 54). Scape short: about three times longer than the pedicel . . . . . 7


 * Masticatory margin of mandible with six or more small, close-set teeth (fig. 55). Scape long: four to five times longer than the pedicel. Pale brown . . . . . 8

7
return to couplet #6
 * First gastric tergum with numerous (> 10) short appressed setae in addition to long suberect to erect setae. Strongly shining black. Mexico south to Brazil . . . . . Megalomyrmex megadrifti


 * First gastric tergum with sparse (< 5) or without short appressed setae in addition to long suberect to erect setae. Red-brown. Costa Rica, Ecuador . . . . . Megalomyrmex brandaoi

8
return to couplet #6
 * Postpetiole with anteroventral denticle in profile view (fig. 56). Ventral surface of petiole with rough sculpturation. All setae on scape appressed. Costa Rica and Panama . . . . . Megalomyrmex miri


 * Postpetiole without anteroventral denticle in profile view (fig. 57). Ventral surface of petiole smooth and shining. Setae on scape appressed to subdecumbent. Costa Rica and Panama . . . . . Megalomyrmex wettereri

9
return to couplet #1
 * Occipital carina distinctly visible in full-face view (fig. 50) . . . . . 10


 * Occipital carina obscured by vertex in full-face view (fig. 51) . . . . . 13

10
return to couplet #9
 * Third antennomere apically flattened and/or bent (fig. 58). Submarginal cell 1+2 of forewing broad: less than or equal to four times as long as broad . . . . . 11


 * Third antennomere cylindrical, not apically bent (fig. 59). Submarginal cell 1+2 of forewing very narrow: five or more times as long as broad . . . . . 12

11
return to couplet #10
 * Postpetiole globose: postpetiolar node and sternum strongly convex in profile view (fig. 60). Masticatory margin of mandible with six teeth; the subapical tooth about one third the length of the apical tooth. Palpal formula 3,2. Costa Rica, Panama, Colombia, Guyana, Amazonian Brazil . . . . . Megalomyrmex wallacei


 * Postpetiole not globose: postpetiolar node and sternum weakly convex in profile view (fig. 61). Masticatory margin of mandible with five teeth; the subapical tooth about half the length of the apical tooth. Palpal formula 3,3. Costa Rica south to Andean regions of Colombia, Ecuador, and northern Peru . . . . . Megalomyrmex foreli

12
return to couplet #10
 * Petiolar node bulbous and with a distinct posterior face in profile view (fig. 62). Postpetiolar node distinct and strongly convex in profile view (fig. 62). Femora and at least first three antennomeres white; tibiae pale brown. Costa Rica . . . . . Megalomyrmex mondabora


 * Petiolar node angular and without a distinct posterior face (fig. 63). Postpetiolar node indistinct, almost linear in profile view (fig. 63). Femora, first three antennomeres, and tibiae dark brown. Chiapas, Mexico . . . . . Megalomyrmex male 01

13
return to couplet #9
 * Antenna with eleven antennomeres. Anterodorsal margin of petiole concave (fig. 64). Metabasitarsus bent about midlength and swollen apically. Southern Mexico south to Peru, Venezuela, and central Brazil; absent in Costa Rica . . . . . Megalomyrmex incisus


 * Antenna with thirteen antennomeres. Anterodorsal margin of petiole linear (fig. 65). Metabasitarsus tubular; neither bent nor swollen apically . . . . . 14

14
return to couplet #13
 * Antenna brown to honey-colored. Large (ML > 2.25 mm). Compound eyes giant, taking up most of the head (fig. 73), separated across the frons by less than one eye width in full-face view. Lateral ocellus less than one lateral ocellus length from compound eye. Dorsal face of propodeum depressed in profile view (fig. 66). Panama . . . . . Megalomyrmex milenae


 * Antenna white. Small (ML < 1.5 mm). Compound eyes smaller, not taking up most of the head (Fig. 77), separated across the frons by more than twice one eye width in full-face view. Lateral ocellus about three lateral ocellus lengths from compound eye. Dorsal face of propodeum convex in profile view (fig. 67). Costa Rica and Panama . . . . . Megalomyrmex mondaboroides