Monomorium areniphilum

Identification
Bolton (1987) - A member of the M. areniphilum complex in the M. salomonis species group. M. areniphilum appears to be a successful circum-Saharan species which shows variation in colour and size over its wide range but which seems consistent in the characters noted in the description. It is accepted that the name as now applied may conceal two or more close but discrete sibling species, but only a detailed investigation of the North African fauna, with its welter of unresolved infraspecific names attached to salomonis and its relatives, will be able to resolve the confusion. I am unable to undertake such a study here, so for the present I regard Monomorium lepineyi and Monomorium pullulum provisionally as junior synonyms of areniphilum, fully realizing that this situation may change once detailed taxonomic investigation is possible.

The single lepineyi syntype available for study matches areniphilum moderately well, but is smaller and darker in colour, being a uniform blackish brown, and has the head narrower than the areniphilum syntypes. The eyes in the lepineyi syntype are slightly larger than in areniphilum and the sides of the head are not as distinctly convergent posteriorly.

The syntypes of pullulum are relatively large specimens but their indices are within the areniphilum range. These syntypes are uniformly dark brown on the head and alitrunk but have a blackish brown gaster. The cephalic sculpture in pullulum, whilst of the same form as in areniphilum, tends to be denser.

Monomorium hemame Lush (2008) - M. hemame is an unusual member of the M. areniphilum complex in the M. salomonis species group due to the presence of erect setae on the first gastral tergite anterior to the apical transverse row. Although it is the only known member of the complex to possess this characteristic, it has the distinctive mesosoma profile absent in all other described species-complexes within the salomonis-group and so is tentatively placed here.

Distribution based on Regional Taxon Lists
Afrotropical Region: Mali, Niger, Saudi Arabia, Senegal, Sudan, United Arab Emirates. Palaearctic Region: Algeria, Egypt, Iran, Kuwait, Lebanon, Oman, Tunisia.

Nomenclature

 *  areniphilum. Monomorium salomonis var. areniphila Santschi, 1911f: 84 (w.) TUNISIA. Emery, 1915e: 378 (q.). Combination in M. (Xeromyrmex): Emery, 1922e: 177. Subspecies of salomonis: Santschi, 1936a: 50. Raised to species: Collingwood, 1985: 269. Senior synonym of lepineyi, pullula: Bolton, 1987: 336.
 * fezzanense. Monomorium fezzanense Collingwood & Agosti, 1996: 346 (w.) SAUDI ARABIA.
 * Junior synonym of areniphilum: Sharaf et al., 2021: 23.
 * hemame. Monomorium hemame Collingwood & Agosti, 1996: 348 (w.) KUWAIT.
 * Junior synonym of areniphilum: Sharaf et al., 2021: 23.
 * lepineyi. Monomorium (Xeromyrmex) salomonis var. lepineyi Santschi, 1934b: 34, figs. 5, 6 (w.) SUDAN.
 * As unavailable (infrasubspecific) name: Santschi, 1936a: 53.
 * Subspecies of salomonis: Ettershank, 1966: 90.
 * Junior synonym of areniphilum: Bolton, 1987: 336; Bolton, 1995b: 263.
 * Status as species: Borowiec, L. 2014: 121 (error).
 * marmule. Monomorium marmule Collingwood & Agosti, 1996: 349, fig. 21 (w.) OMAN.
 * Junior synonym of areniphilum: Sharaf et al., 2021: 23.
 * pullula. Monomorium (Xeromyrmex) salomonis var. pullula Santschi, 1919: 235 (w.) SENEGAL.
 * As unavailable (infrasubspecific) name: Santschi, 1936a: 53.
 * Subspecies of salomonis: Wheeler, W.M. 1922a: 870; Santschi, 1934b: 33.
 * Junior synonym of areniphilum: Bolton, 1987: 336; Bolton, 1995b: 266.
 * Status as species: Borowiec, L. 2014: 124 (error).

Type Material
Monomorium salomonis areniphila: Bolton (1987) - Syntype workers, Tunisia: Gabes, 1906 (A. Weiss); Kebili, 1907; Kairouan (Santschi) [examined].

Monomorium fezzanense: Holotype: worker, Saudi Arabia, Jabal Banban, 16.III.1978, W Biittiker. - Paratypes: Saudi Arabia: workers, same series as holotype; workers, N of Tabuk, 4.IY.1979; Exp. N. Hedjaz (W Buttiker); workers, Al-Tawlah, 7.III.1983, CA. Collingwood. - Oman: workers, Khabura Barina, 2.VI.1979, R.P. Whitcombe; workers, Thumrait, 1.V.1984, J .M. Barnes.

Monomorium hemame: Holotype: worker, Kuwait, Umm al-Hemam, 9.III.1988, W. Buttiker. - Paratypes: Kuwait: workers, same series as holotype. - Saudi Arabia: workers, Uyaynah, 1.IV.1976, W. Buttiker.

Monomorium marmule: Holotype: worker, Oman, Marmul, IX.1989, M.D. Gallagher. - Paratypes: Oman: workers, same series as holotype; workers from: Yalooni, 3.X.1984; Minririb, 14.I.1986; all M.D. Gallagher; 99, Yalooni, 18.XI.1984, R. Braund.

Worker
Bolton (1987) - Worker. TL 3.1-4.3, HL 0.86-1.04, HW 0.67-0.88, CI 78-88, SL 0.68-0.88, SI 98-104, PW 0.40-0.53, AL 0.95-1.24 (30 measured).

Anterior margin of median portion of clypeus evenly shallowly concave. Eyes large, the maximum diameter 0.30-0.35 x HW and with 12-14 ommatidia in the longest row. Sides of head evenly shallowly convex in full-face view, the occipital margin approximately transverse to broadly but shallowly concave. Pronotum and anterior portion of mesonotum in profile evenly convex; median portion of mesonotum flat to shallowly convex, sometimes even slightly indented; posterior one-third (approximately) of mesonotum suddenly sloping much more steeply to the conspicuously impressed metanotal groove. Highest point of propodeal dorsum behind the metanotal groove on a much lower level than the highest point of the promesonotum. In dorsal view the propodeum with a narrow flattened median longitudinal strip, the dorsum and sides separated by bluntly rounded margins.

Dorsum of head with 1-2 pairs of standing hairs, which straddle the midline; occipital corners without hairs. Dorsal alitrunk without standing hairs. Petiole node with one pair, postpetiole with 2-3 pairs (very rarely with 4 pairs) of backward directed hairs. First gastral tergite without standing hairs except for the apical transverse row, or at most with a single pair at or near the midlength of the sclerite.

Dorsum of head with fine dense reticulate to reticulate-shagreenate sculpture; this often extensively overlaid, especially mid-dorsally, by exceptionally fine dense scratch-like longitudinal sculpture. Dorsal alitrunk reticulate to shallowly reticulate-punctate, the propodeum more strongly sculptured than the pronotum; intensity of sculpture variable between series. First gastral tergite at least with superficial reticular patterning, more often this is overlaid by a secondary fine shagreening. Colour brown, very variable in shade.

I am grouping the names areniphilum, lepineyi and pullulum as a single species here, based on the following combination of five characters within the Salomonis-group.


 * Eyes both relatively and absolutely large (see measurements above).
 * Antennal scapes of moderate length (SI 98-104).
 * Characteristic outline shape of dorsal alitrunk (as in Fig. 46).
 * Cephalic sculpture (as described).
 * Very reduced dorsal pilosity (as described).

References based on Global Ant Biodiversity Informatics

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