Monomorium, Collingwood, C. A., Pohl, F., Güsten, R., Wranik, W., van Harten, A., 2004

Collingwood, C. A., Pohl, F., Güsten, R., Wranik, W., van Harten, A., 2004, The ants (Insecta: Hymenoptera: Formicidae) of the Socotra Archipelago, Fauna of Arabia 20, pp. 473-495 : 485-486

Monomorium nimihil Collingwood n. sp. Fig. 12

Holotype: ☿, Yemen, Socotra Island, Wadi Daneghan , 12°37N 54°04'E, 90 m, pitfall trap, 28-30.X.2000, A. van Harten & H. Pohl, HLMD-Hym-2087-HT . - Paratypes : Yemen, Socotra Island: 3 ☿☿, same data as holotype, HLMD-Hym-2087-PT1 to -PT3 [ HLMD-Hym-2087-PT3 preserved as SEM preparation] ; 4 ☿☿, same data as holotype, NHCY ; 4 ☿☿, same data as holotype, CCC ; 1 ☿, same data as holotype, BMNH .

Diagnosis: The combination of sculptured mandibles, circular propodeal spiracle and round eyes near the midlength of head sides places Monomorium nimihil n. sp. in the M. salomonis-group sensu Bolton (1987). Almost unsculptured dorsal surfaces of head and alitrunk in conjunction with numerous long hairs in these areas are not found in any other African or Arabian representative of that species-group.

Measurements and indices: AL 0.71 mm, HL 0.63 mm, HW 0.59 mm, SL 0.63 mm, CI 94, SI 106 (4 specimens measured).

Description: Head almost square with mildly convex sides and slightly concave occiput. Many long hairs present over the whole body, slightly shorter on the ventral head. Scapes and legs thickly clothed with suberect pubescence. Eyes, placed medially, relatively large (diameter 0.30 times the HW) with 10-11 ommatidia in the longest row. Petiole and postpetiole nodes wider than long in dorsal view ( PW = 0.30 x HW). Body colour entirely yellow, shining with very superficial sculpture on the head and propodeum.

Affinities: In body profile and with the abundant pilosity, M. nimihil n. sp. is quite like the southern African M. albopilosum Emery, 1895 - a member of the M. opacum -complex of the M. salomonis-group. However, M. albopilosum is much larger ( HL ~ 0.91 mm, HW ~ 0.68 mm) with comparatively smaller eyes (diameter at most 0.25 times the HW) and has - as all species in the M. opacum -complex - conspicuous reticulate-punctate sculpture on head and alitrunk. Only one other African species of the M. salomonis-group, M. hirsutum Forel, 1910 , and one Arabian species, M. yemene Collingwood & Agosti, 1996 , are densely hairy. They belong to the M. bicolor complex and thus have a distinctly contrasting dark gaster, are even more strongly sculptured than M. albopilosum and have even smaller eyes.

Remarks: The new species was only encountered in one sample, procured from pitfall traps set up on a steep slope near a permanent brook, among well-developed leaf and humus layers under and around fig trees (most likely Ficus cordata var. salicifolia (Vahl) C.C. Berg). In the samples from these traps, it was the most numerous ant (13 of 34 specimens).

The authorship of the name of this species is to be attributed to the senior author. Etymology: The specific name (a noun in apposition) is the term for “ant” in the Socotri language.