Key to Cylindromyrmex workers

This worker key is based on: [[Media:DeAndrade 1998a.pdf|De Andrade, M. L. 1998a. Fossil and extant species of Cylindromyrmex (Hymenoptera: Formicidae). Revue Suisse de Zoologie. 105:581-664. PDF]] with revisions as given in De Andrade 2001.

The workers of Cylindromyrmex boliviae and Cylindromyrmex godmani are not included in this key because they are not yet known.

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1

 * Eyes large and convex (≥ 400 ommatidia). Ocelli present and well defined. . . . . . 2


 * Eyes small or of medium size (> 16 and < 200 ommatidia), flat or slightly convex. Ocelli absent or represented by superficial pits . . . . . 4

2
return to couplet #1
 * Legs dark orange to light brown. Dorsum of the petiole with thin, irregular striae. Brazil, Paraguay . . . . . Cylindromyrmex brasiliensis


 * Legs dark orange ferrugineous black, with at least part of the tibiae yellowish. Dorsum of the petiole with thick, regular striae . . . . . 3

3
return to couplet #1
 * Posterior third of the head dorsum at most with 25 striae. Postpetiole with 19-25 longitudinal striae. Guatemala, Costa Rica, Galapagos Is., Ecuador, Peru, Bolivia, Chile, Brazil . . . . . Cylindromyrmex whymperi


 * Posterior third of the head dorsum with more than 34 striae. Postpetiole with about 29-30 striae. Surinam, French Guyana, Brazil . . . . . Cylindromyrmex striatus

4
return to couplet #2
 * Head length (mandibles excluded) ca. 1/3 longer than broad; frons, slightly more than 1/3 of the head width. Mandibles dorsally flat . . . . . 5


 * Head length (mandibles excluded) ca. 1/5 longer than broad; frons broad, slightly less than ½ or more than ½ of the head width. Mandibles dorsally convex. . . . . . 6

5
return to couplet #4
 * Frontal carinae not reaching the anterior clypeal border. Pygidium with a semicircle of teeth of similar size. Brazil . . . . . Cylindromyrmex longiceps


 * Frontal carinae reaching the anterior clypeal border. Pygidium with a semicircle of teeth with two larger ones over the sting. Costa Rica, Panama, Venezuela, Brazil . . . . . Cylindromyrmex meinerti

6
return to couplet #4
 * Frontal carinae not reaching the anterior clypeal border. Clypeus strongly convex medially. Gaster without striation. Mesosoma, petiole and legs elongate. Hind femora Index (HFeI) = 37. Colombia . . . . . Cylindromyrmex escobari


 * Frontal carinae reaching or surpassing the anterior clypeal border. Clypeus not strongly convex medially. At least the first gastric tergite with thin striation on the anterior part. Mesosoma, petiole and legs stout. Hind femora Index (HFeI) ≥ 45 . . . . . 7

7
return to couplet #6
 * Frontal carinae surpassing the anterior clypeal border. Mandibles with 9-10 denticles. Scape Index (SI) = 37. Cuba . . . . . Cylindromyrmex darlingtoni


 * Frontal carinae reaching the anterior clypeal border. Mandibles with 6-7 denticles. Scape Index (SI) > 42. Venezuela, Ecuador, Peru and Brazil . . . . . Cylindromyrmex brevitarsus