Key to Malagasy Nesomyrmex angulatus group workers

This worker key to the exclusively Malagasy N. angulatus group is based on: Csosz, S. & Fisher, B.L. 2016. Taxonomic revision of the Malagasy members of the Nesomyrmex angulatus species group using the automated morphological species delineation protocol NC-PART-clustering. PeerJ 4:e1796 doi:10.7717/peerj.1796

Note: absolute size is given in mm, indexes are dimensionless values minimum and maximum values are given in brackets. Classification power between couplet based on a certain character is calculated and percent value is given in parentheses.

1

Median clypeal notch present: Cdep (mm) = 19 [15, 23] . . . . . Nesomyrmex clypeatus

Median clypeal notch absent, anterior edge of clypeus intact and convex . . . . . 2

2

return to couplet #1

Anterolateral corner of pronotum angulate in dorsal wiew. Frontal carina narrow, scape longer: FRS/SL < 0.5 (100%) . . . . . Nesomyrmex angulatus

Anterolateral corner of pronotum rounded in dorsal view. Frontal carina wide, scape shorter: FRS/SL > 0.5 (100%) . . . . . 3

3

return to couplet #2

Propodel spines short: SPST/CS D 0.286 [0.220, 0.356] (94.9%). In lateral view dorsal contour line of propodeal spine or tubercle continues in a flat transition into metasomal dorsum. Postpetiole narrower, mesosoma longer: PPW/ML < 0.38 [0.317, 0.386] (96.8%). Combination of best ratios (PPW/ML and MPST/SPST) yields 99.7% of correct classification . . . . . 4 (bidentatus complex)

Propodeal spines longer and acute: SPST/CS D 0.378 [0.301, 0.446], (94.9%). In lateral view dorsal contour line of propodeal spine continues in bent transition to metasomal dorsum. Postpetiole wider, mesosoma shorter: PPW/ML > 0.36 [0.369, 0.440] (96.8%). Combination of best ratios (PPW/ML and CW/SPST) yields 99.4% of correct classification . . . . . 5 (devius complex)

4

return to couplet #3

Propodeal spine very short: SPST CS D 0.264 [0.220, 0.335] (84.2%), forming blunt tubercle. Postocular distance longer, apical spine distance shorter: PoOC/SPTI D 1.396 [1.233, 1.658] (93.1%). Combination of best ratios (PoOC/SPTI and ML/PEH) yields 97.1% of correct classification . . . . . Nesomyrmex bidentatus

Propodeal spine moderately long: SPST CS D 0.307 [0.257, 0.356] (84.2%) and acute. Postocular distance longer, apical spine distance shorter: PoOC/SPTI D 1.185 [1.044, 1.341] (93.1%). Combination of best ratios (PoOC/SPTI and ML/PEH) yields 97.1% of correct classification . . . . . Nesomyrmex fragilis

5

return to couplet #3

North Madagascar only, north of -15° latitude . . . . . 6

The middle and southern part of Madagascar, south of -15° latitude . . . . . 7

6

return to couplet #5

In profile, petiolar node rounded, leaning backward. Postocular distance longer, apical spine distance shorter: PoOC/SPTI D 1.029 [0.929, 1.179] (94.5%). Combination of best ratios (PoOC/SPTI and CWb/ML) yields 100% of classification success . . . . . Nesomyrmex exiguus

In profile, petiolar node rectangular. Postocular distance shorter, apical spine distance longer: PoOC/SPTI D 0.866 [0.773, 0.965] (94.5%). Combination of best ratios (PoOC/SPTI and CWb/ML) yields 100% of classification success . . . . . Nesomyrmex gracilis

7

return to couplet #5

Postocular distance longer, apical spine distance shorter: PoOC/SPST D 1.261 [1.163, 1.382] (92.2%). Combination of best ratios (PoOC/SPST and MW/PPH) yields 100% of classification success . . . . . Nesomyrmex devius

Postocular distance shorter, apical spine distance longer: PoOC/SPST D 1.122 [0.991, 1.250] (92.2%). Combination of best ratios (PoOC/SPST and MW/PPH) yields 100% of classification success . . . . . Nesomyrmex hirtellus