Key to Malagasy Crematogaster Orthocrema workers

This worker key is based on: Blaimer, B.B. 2012. Taxonomy and species-groups of the subgenus Crematogaster (Orthocrema) in the Malagasy region (Hymenoptera, Formicidae). ZooKeys, 199, 23-70. doi:10.3897/zookeys.199.2631

Blaimer noted in regards to this key: Crematogaster volamena and C. mpanjono can only be reliably identified based on queen characters and genetic data.

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1

 * Petiole in dorsal view rectangular (Figure 3), with both antero- and posterolateral denticles; abdominal tergite 4 with sparse erect pilosity, often only a single row of setae towards posterior end . . . . . Crematogaster rasoherinae


 * Petiole in dorsal view ovo-rectangular (Figure 4A), with only posterolateral denticles present; abdominal tergite 4 with abundant erect pilosity throughout . . . . . 2

2
return to couplet #1
 * Occipital carinae distinct and sharp (Figure 12); eyes larger (OI 0.22–0.28) and distinctly protruding (as in Figure 27A and 29A); propodeum with raised, sharp lateral carinae, confluent with propodeal spines (Figure 13) . . . . . 3


 * Occipital carinae indistinct (Figure 14); eyes smaller (OI 0.18–0.22) and less protruding (as in Figure 31A and 33A); propodeum lacking raised, sharp lateral carinae (Figure 15) . . . . . 5

3
return to couplet #2
 * One pair of long, flexuous setae present on posterior end of lateral mesonotal carinae; clypeus with two distinct median vertical carinae (Figure 16); antennal scapes reaching, or well surpassing posterior margin of head (SI 0.78–1.01); subpostpetiolar process usually present . . . . . 4


 * Long, flexuous setae absent from posterior end of lateral mesonotal carinae; clypeus lacking median vertical carinae (Figure 17); antennal scapes shorter, barely reaching head margin (SI 0.74–0.77); subpostpetiolar process absent. . . . . . Crematogaster razana

4
return to couplet #3
 * Antennal scapes well surpassing posterior margin of head (SI 0.85–1.01); propodeal spines medium-sized (SPI 0.17–0.26), usually thin and acute (Figure 18A), in lateral view directed upwards but straight . . . . . Crematogaster madecassa


 * Antennal scapes just reaching posterior margin of head (SI 0.78–0.87); propodeal spines shorter (SPI 0.10–0.19), usually in form of acute triangular points (Figure 18B), if more elongate and spiniform, then distinctly curved upwards (Figure 18C) . . . . . Crematogaster telolafy

5
return to couplet #2
 * Propodeal spines shorter (SPI 0.06–0.09); propodeum often with longer erect pilosity; rare, Madagascar: Nosy Bé, R.S. Manongarivo, Ile St. Marie . . . . . Crematogaster mpanjono


 * Propodeal spines often longer (SPI 0.06–0.12); propodeum lacking longer erect pilosity; more common, eastern rainforests of Madagascar . . . . . Crematogaster volamena