Key to Rhopalomastix of Southeast Asia

This key to workers is based on a key from: Wang W. Y., G. W. J. Yong, and W. Jaitrong. 2018. The ant genus Rhopalomastix (Hymenoptera: Formicidae: Myrmicinae) in Southeast Asia, with descriptions of four new species from Singapore based on morphology and DNA barcoding. Zootaxa. 4532:301-340.

1

In profile, lateral surface of posterior half of head largely smooth and shiny; ventral surface of head largely smooth and shiny, with sparse superficial reticulate sculpture or feeble striations; outer surface of femora largely smooth and shiny, sometimes feebly reticulate . . . . . 2

In profile, lateral surface of posterior half of head largely striate and/or reticulate ; ventral face of head striate, punctate and/or reticulate with smooth and shiny interspaces; outer face of femora superficially reticulate with smooth and shiny interspaces . . . . . 3

2

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Anterior face of petiole smooth and shiny, without short appressed or decumbent hairs . . . . . Rhopalomastix murphyi

Wang, Yong, Jaitrong 2018. Figures 40–43. Paratype worker of Rhopalomastix murphyi 40). habitus in profile; 41). head in full-face view; 42). closeup of head in profile view; 43). body in dorsal view.

Anterior face of petiole weakly punctate or smooth, with short appressed or decumbent hairs. . . . . Rhopalomastix glabricephala

Wang, Yong, Jaitrong 2018. F4-7. Holotype worker of Rhopalomastix glabricephala 4). habitus in profile; 5). head in full-face view; 6). closeup of head in profile view; 7). body in dorsal view.

3

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Figure 2. Dorsal views of anterior pronotal margin of four Rhopalomastix species. 2A, R. striata; 2B, R. javana; 2C, R. johorensis; 2D, R. tenebra.

In dorsal view, anterior pronotal margin strongly convex, distinctly angulate medially (Fig. 2A); clypeus in profile view evenly and roundly convex (Fig. 3A) . . . . . Rhopalomastix striata

Figure 3. Profile views of clypeus of four Rhopalomastix species. 3A, R. striata; 3B, R. javana; 3C, R. johorensis; 3D, R. tenebra.

Wang, Yong, Jaitrong 2018. Figures 52–55. Holotype worker of Rhopalomastix striata 52). habitus in profile; 53). head in full face view; 54). closeup of head in profile view; 55). body in dorsal view.

In dorsal view, anterior pronotal margin broadly convex or weakly angulate medially (Figs. 2B–D); clypeus in profile view variable—almost entirely straight and flat, or very weakly convex (Figs. 3B–D) . . . . . 4

4

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Vertexal lobe of head largely smooth and shining, sometimes with sparse and fragmented striae; head and dorsum of meso-soma darker blackish-brown than rest of body . . . . . Rhopalomastix tenebra

Wang, Yong, Jaitrong 2018. Figures 64–67. Holotype worker of Rhopalomastix tenebra 64). habitus in profile; 65). head in full face view; 66). closeup of head in profile view; 67). body in dorsal view.

Vertexal lobe of head largely finely striated and shining, sometimes striae fragmented and sparse; body colour uniformly brown . . . . . 5

5

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Posteriormost portion of vertex just above occiput in posterodorsal view largely unsculptured, smooth and shiny; petiolar node in dorsal view more strongly convex anteriorly than posteriorly . . . . . Rhopalomastix javana

Wang, Yong, Jaitrong 2018. Figures 8–11. Lectotype worker of Rhopalomastix javana 8). habitus in profile; 9). head in full-face view; 10). closeup of head in profile view; 11). body in dorsal view.

Posteriormost portion of vertex striate but slightly shiny; petiolar node in dorsal view similarly convex anteriorly and posteriorly . . . . . Rhopalomastix johorensis

Wang, Yong, Jaitrong 2018. Figures 24–27. Lectotype worker of Rhopalomastix johorensis 24). habitus in profile; 25). head in full-face view; 26). closeup of head in profile view; 27). body in dorsal view.