Nesomyrmex angulatus (Mayr, 1862)

Garcia, Francisco Hita, Mbanyana, Nokuthula, Audisio, Tracy Lynn & Alpert, Gary D., 2017, Taxonomy of the ant genus Nesomyrmex Wheeler (Formicidae, Myrmicinae) in the Afrotropical region, with a review of current species groups and description of a new species of the N. angulatus group from Mozambique, European Journal of Taxonomy 258, pp. 1-31 : 12-15

Identification key to Afrotropical species of the N. angulatus species group (workers)

Review of the Nesomyrmex angulatus species group

The following key is partly based on Bolton (1982) and Mbanyana & Robertson (2008).

1. In profile mesosomal dorsum forming a single, uninterrupted flat surface without any trace of metanotal groove; petiolar peduncle short ( Fig. 8A ) …………………………………………………2

– In profile mesosomal dorsum always with conspicuously impressed metanotal groove; petiolar peduncle long ( Fig. 8B ) ……………………………………………………………………………3

2. Body colour yellow to very light brown ( Fig. 9A ) …………………… N. angulatus ( Mayr, 1862)

– Body colour very dark brown to black ( Fig. 9B ) ……………………… N. grisoni ( Forel, 1916)

3. First gastral tergite lacking standing hairs except for single transverse row on posterior end of tergite ( Fig. 10A ) ………………………………………………………… N. evelynae ( Forel, 1916)

– First gastral tergite with standing hairs evenly distributed throughout ( Fig. 10B ) ………………4

4. Antennal scapes conspicuously longer (SI 95–98); in dorsal view sides of petiolar node straight to weakly rounded, not laterally denticulate ( Fig. 11A ); dorsum of propodeum without standing hairs ( Fig. 11B ) ………………………………………………………………………… N. inhaca sp. nov.

– Antennal scapes conspicuously shorter (SI 67–77); in dorsal view petiolar node laterally denticulate ( Fig. 11C ); dorsum of propodeum with short standing hairs ( Fig. 11D ) ………………5

5. Eyes larger, with 10–12 ommatidia in longest row ( Fig. 12A ); subpetiolar process with a conspicuous tooth anteriorly, followed by a long cuticular flange running back to the postpetiolar junction ( Fig. 12A ) …………………………………………………… N. denticulatus ( Mayr, 1901)

– Eyes smaller, with 7–9 ommatidia in longest row ( Fig. 12B ); subpetiolar process with or without a conspicuously developed tooth anteriorly, but without a long cuticular flange running back to the postpetiolar junction ( Fig. 12B ) ……………………………………………………………………6

6. Propodeal spines shorter and thicker, elongate-triangular and only weakly longer than their basal width; in profile petiolar node nodiform, appearing approximately as long as high ( Fig. 13A ) …………………………………………………………………………… N. innocens ( Forel, 1913)

– Propodeal spines longer and thinner, several times longer than their basal width; in profile petiolar node high, rectangular nodiform, appearing around twice as high as long ( Fig. 13B ) ……………………………………………………………………… N. stramineus ( Arnold, 1948)

Figures

Fig. 8. Body in profile. A. Nesomyrmex angulatus (Mayr, 1862) (CASENT0922010). B. N. stramineus (Arnold, 1948) (CASENT0922011).

Fig. 9. Body in profile. A. Nesomyrmex angulatus (Mayr, 1862) (CASENT0922010). B. N. grisoni (Forel, 1916) (CASENT0908994).

Fig. 10. Body in profile. A. Nesomyrmex evelynae (Forel, 1916) (CASENT0413068). B. N. denticulatus (Mayr, 1901) (CASENT0908992).

Fig. 11. Waist segments in dorsal view and mesosoma in profile. A–B. Nesomyrmex inhaca sp. nov. (CASENT0790016). C. N. denticulatus (Mayr, 1901) (CASENT0914923). D. N. denticulatus (Mayr, 1901) (CASENT0908992).

Fig. 12. Head, mesosoma, and waist segments in profile. A. Nesomyrmex denticulatus (Mayr, 1901) (CASENT0914923). B. N. innocens (Forel, 1913) (CASENT0906195).

Fig. 13. Mesosoma and waist segments in profile. A. Nesomyrmex innocens (Forel, 1913) (CASENT0908995). B. N. stramineus (Arnold, 1948) (CASENT0922011).