Worker. TL 3.4-4.4, HL 0.80-1.02, HW 0.58-0.78, CI 73-78, SL 0.68-0.90, SI 110-120, PW 0.42-0.52, AL 1.00-1.32 (30 measured).
Median portion of anterior clypeal margin concave. Head relatively long and narrow, scapes long (CI and SI, above). Eyes of moderate size, the maximum diameter 0.22-0.25 x HW and with 10-12 ommatidia in the longest row. Petiole node high and conical in profile; in dorsal view the two nodes usually of about equal width but sometimes the petiole slightly broader. Sculpture usually of fine dense and sharply defined reticulate-punctation all over the head and alitrunk, but sometimes it is reduced on the head posteriorly, or on the pronotum, or both. Petiole and postpetiole weakly reticulate-punctate to virtually smooth. Gaster shining but first tergite at least with superficial shagreening.
Entire body abundantly hairy; all dorsal surfaces of head and body with dense standing pilosity and sides of head in full-face view with freely projecting hairs both in front of and behind the eyes. Pubescence and pilosity of scapes and tibiae elevated, not appressed. Colour uniform light to dark brown, sometimes the gaster slightly darker than the head and alitrunk.
One of only two very densely hairy species within the salomonis-group as it is represented in sub-Saharan Africa, the abundant pilosity of albopilosum will isolate this species from all others in the group except hirsutum. This latter species, however, shows the strongly contrasting colours of the bicolor-complex and has a broader head and shorter scapes than in albopilosum; compare the hirsutum CI of 81-83 and SI of 99-103 with the measurements given above.
Within the opacum-complex only junodi and albopilosum have hairs present on the dorsal alitrunk, but junodi these are sparse and do not occur on the propodeum, whereas in albopilosum dense pilosity is present everywhere.
Keys including this Species
Distribution based on Regional Taxon Lists
Distribution based on AntMaps
Distribution based on AntWeb specimens
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The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- albopilosum. Monomorium albopilosum Emery, 1895h: 24 (w.) SOUTH AFRICA. Combination in M. (Xeromyrmex): Santschi, 1919b: 235. Senior synonym of clarithorax, fingo, paucipilosa, thales: Bolton, 1987: 335.
- thales. Monomorium albopilosum var. thales Forel, 1913a: 136 (w.) ZIMBABWE. Arnold, 1916: 208 (q.m.). Junior synonym of albopilosum: Bolton, 1987: 335.
- clarithorax. Monomorium (Xeromyrmex) albopilosum var. clarithorax Santschi, 1919b: 235 (w.) SOUTH AFRICA. Junior synonym of albopilosum: Bolton, 1987: 335.
- paucipilosa. Monomorium (Xeromyrmex) albopilosum st. paucipilosa Santschi, 1919b: 235 (w.) SOUTH AFRICA. Junior synonym of albopilosum: Bolton, 1987: 335.
- fingo. Monomorium albopilosum subsp. fingo Arnold, 1946: 61, fig. 13 (w.) SOUTH AFRICA. Junior synonym of albopilosum: Bolton, 1987: 335.
- Bolton, B. 1987. A review of the Solenopsis genus-group and revision of Afrotropical Monomorium Mayr (Hymenoptera: Formicidae). Bull. Br. Mus. (Nat. Hist.) Entomol. 54: 263-452 (page 335, Senior synonym of clarithorax, fingo, paucipilosa and thales)
- Emery, C. 1895i. Voyage de M. E. Simon dans l'Afrique australe (janvier-avril 1893). 3e mémoire. Formicides. Ann. Soc. Entomol. Fr. 64: 15-56 (page 24, worker described)
- Santschi, F. 1919b. Fourmis nouvelles éthiopiennes. Rev. Zool. Afr. (Bruss.) 6: 229-240 (page 235, Combination in M. (Xeromyrmex))