Key to Tetramorium plesiarum-group species

This worker key is based on: Hita Garcia, F. & Fisher, B.L. 2014. The hyper-diverse ant genus Tetramorium Mayr (Hymenoptera, Formicidae) in the Malagasy region ‑ taxonomic revision of the T. naganum, T. plesiarum, T. schaufussii, and T. severini species groups. ZooKeys 413, 1–170 (doi: 10.3897/zookeys.413.7172).

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• Tetramorium plesiarum species group (species list, diagnosis, distribution, etc.)
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1

• Gaster conspicuously enlarged, appearing swollen; basal half of first gastral tergite strongly sculptured (Fig. 11A) [Madagascar] . . . . . Tetramorium gollum

• Gaster never enlarged or swollen; first gastral tergite not strongly sculptured; if sculpture present, then restricted to base of the tergite (Fig. 11B, C) . . . . . 2

Hita Garcia and Fisher, 2014. Figure 11.

2

return to couplet #1

• Petiolar node blocky, massive and very large; head, mesosoma, and waist segments with conspicuous reticulate-punctate ground sculpture (Fig. 12A) [Madagascar] . . . . . Tetramorium hobbit

• Petiolar node always much smaller than above; head, mesosoma, and waist segments without conspicuous reticulate-punctate ground sculpture (Fig. 12B, C) . . . . . 3

Hita Garcia and Fisher, 2014. Figure 12.

3

return to couplet #2

• Antennal scapes shorter (SI 58–62); petiolar node in profile lower and thicker and in dorsal view longer (LPeI 69–76; DPeI 108–123); dorsum of petiolar node fully covered with distinctly reticulate-rugose sculpture (Fig. 13A) [Madagascar] . . . . . Tetramorium mars

• Antennal scapes longer (SI 62–69); petiolar node in profile higher and thinner and in dorsal view broader (LPeI 56–63; DPeI 130–144); dorsum of petiolar node weakly rugulose/rugose, mostly smooth (Fig. 13B, C) . . . . . 4

Hita Garcia and Fisher, 2014. Figure 13.

4

return to couplet #3

• Generally smaller species (HW 0.67–0.76; WL 0.81–092); eyes relatively larger (OI 21–23); in profile anterodorsal margin of petiolar node clearly protruding anteriorly; mesopleuron and lateral propodeum longitudinally rugose with distinct reticulate-punctate ground sculpture, appearing matte and rough; sides of petiolar node with strong reticulate-punctate ground sculpture, appearing fairly matte and rough (Fig. 14A) [Madagascar] . . . . . Tetramorium plesiarum

• Generally larger species (HW 0.80–1.00; WL 0.92–1.15); eyes relatively smaller (OI 18–19); in profile anterodorsal margin of petiolar node not protruding anteriorly; mesopleuron and lateral propodeum with very little rugose/rugulose sculpture, mostly unsculptured, smooth, and shining; sides of petiolar node with weak but distinct reticulate-punctate ground sculpture, appearing only slightly matte and mostly smooth and shining (Fig. 14B) [Madagascar] . . . . . Tetramorium bressleri

Hita Garcia and Fisher, 2014. Figure 14.