Key to Arabian Trichomyrmex species

This worker key is based on: Sharaf, M.R., Salman, S., Al Dhafer, H.M., Akbar, S.A., Abdel-Dayem, M.S. and Aldawood, A.S. 2016. Taxonomy and distribution of the genus Trichomyrmex Mayr, 1865 (Hymenoptera: Formicidae) in the Arabian Peninsula, with the description of two new species. European Journal of Taxonomy. 246:1-36. (DOI 10.5852/ejt.2016.246).

You may also be interested in

Trichomyrmex

1

• Underside of head with abundant long ammochaete J-shaped hairs forming a distinct psammophore (Fig. 1A) . . . . . 2

Figure 1A.

Figure 1B

• Underside of head with scattered short hairs or few long hairs but not forming a distinct psammophore (Fig. 1B) . . . . . 4

2

return to couplet #1

• Unicolorous black species. Eyes reniform in profile, with distinctly concave ventral margin and broadly convex dorsal margin. Propodeal dorsum making an obtuse angle with propodeal declivity in profile. Posterior margin of head strongly concave in full-face view (Saudi Arabia) . . . . . Trichomyrmex almosayari

• Bicoloured species. Head, mesosoma, petiole and appendages brown or reddish brown, gaster brown or blackish brown. Eyes nearly oval in profile (Fig. 1D). Propodeal dorsum making a continuous curve with propodeal declivity in profile (Fig. 1D). Posterior margin of head nearly straight or feebly concave in full-face view . . . . . 3

Figure 1D.

3

return to couplet #2

• Smaller species (TL 3.27, HL 0.88, HW 0.88, PW 0.45). Scapes distinctly longer; when laid back from their insertions scapes reach the posterior margin of the head (SI 82) (Fig. 1E). Posterior margin of head nearly straight or shallowly concave (Fig. 1E). Cephalic dorsum between frontal carinae and in front of eyes longitudinally rugulose with posterior half slightly shining (Fig. 1E) (Algeria, Saudi Arabia, United Arab Emirates) . . . . . Trichomyrmex chobauti

Figure 1E.

• Larger species (TL 4.06–4.50, HL 0.95–1.09, HW 1.00–1.15, PW 0.60–0.61). Scapes shorter; when laid back from their insertions scapes just reach level of posterior margin of eyes (SI 53–65) (Fig. 1F). Posterior margin of head shallowly but distinctly emarginated medially in full-face view (Fig. 1F). Cephalic dorsum distinctly finely and densely longitudinally costulate and completely dull (Fig. 1F) (Algeria, United Arab Emirates) . . . . . Trichomyrmex lameerei

Figure 1F.

4

return to couplet #1

• Propodeal spiracle vertically slit-shaped or elliptical (Fig. 2A). Anterior clypeal margin with a pair of well-developed strong teeth which overhang the mandibles, these teeth broadly separated by a distance greater than maximum width across frontal lobes (Fig. 2B) . . . . . 5

Figure 2A.

Figure 2B.

• Propodeal spiracle circular or subcircular (Fig. 2C). Anterior clypeal margin without teeth (Fig. 2D) . . . . . 6

Figure 2C.

Figure 2D.

5

return to couplet #4

• Promesonotum in profile distinctly convex (Fig. 2E). Propodeal dorsum about twice as long as declivity in profile (Fig. 2E). Propodeum, petiole and postpetiole irregularly rugulose (Fig. 2F) (Benin, Burkina Faso, Eritrea, Ethiopia, Ghana, Nigeria, Sudan, Tanzania, United Arab Emirates) . . . . . Trichomyrmex abyssinicus

Figure 2E

Figure 2F

• Promesonotum in profile flat (Fig. 3A). Propodeal dorsum as long as declivity in profile (Fig. 3A). Propodeum sides, petiole and postpetiole finely punctate-reticulate (Fig. 3A) (Armenia, Cyprus, Greece, Turkey, Jordan, Syria, United Arab Emirates) . . . . . Trichomyrmex perplexus

Figure 3A.

6

return to couplet #4

• Unicolorous yellow species. Propodeal dorsum densely punctulate-reticulate (Fig. 3B). Eyes conspicuously larger (EI 31–37) (Fig. 3C) (Saudi Arabia) . . . . . Trichomyrmex shakeri

Figure 3B.

• Unicolorous dark brown or reddish brown; or bicoloured species with at least gaster distinctly darker than rest of body. Propodeal dorsum finely transversely striolate or transversely rugulose (Fig. 3D). Eyes conspicuously smaller (EI 15–18) . . . . . 7

Figure 3D.

7

return to couplet #6

• Head and mesosoma yellow (India, Pantropical tramp species) . . . . . Trichomyrmex destructor

• Head and mesosoma brown or reddish brown . . . . . 8

8

return to couplet #7

• Posterior margin of head transversely striolate in dorsal view (Fig. 3E). Promesonotum in profile nearly flat or weakly convex (Fig. 3F). Propodeal dorsum in profile making a continuous curve with propodeal declivity. Transverse sculpture of propodeal dorsum fine and dense. Pilosity of mesosoma, petiole, postpetiole and gaster short, and weakly curved (India, North Africa, Middle East, Afrotropical, Indomalayan and Oriental regions) . . . . . Trichomyrmex mayri

Figure 3E.

Figure 3F.

• Posterior margin of head transversely smooth in dorsal view. Promesonotum in profile strongly convex (Fig. 4B). Propodeal dorsum in profile making a weak but distinct obtuse angle with propodeal declivity (Fig. 4B). Transverse sculpture of propodeal dorsum coarse and broadly spaced. Pilosity of mesosoma, petiole, postpetiole and gaster longer, and strongly curved (Fig. 4C) (Somalia, Afrotropical and Malagasy regions) . . . . . Trichomyrmex robustior

Figure 4B.

Figure 4C.