Monomorium dryhimi

Aldawood & Sharaf (2011) - The Monomorium dryhimi type was taken from a nest under a stone on hard-packed soil which contained tens of workers and was found in relatively elevated area of a valley which is high enough to avoid direct impacts of flooding. No additional nests were found despite extensive surveys. In addition, we were not able to collect foraging workers near the nest. It appears that members of the Monomorium monomorium group may prefer inhabiting areas of high elevations. All the four Arabian species were found inhabiting elevated localities with more than 1800 m asl., except Monomorium clavicorne which was also recorded from both relatively lower elevated areas including Riyadh and Al Qatif, in Central and Eastern regions of Saudi Arabia, respectively, and also from a much elevated area, Fayfa, Asir province (Collingwood 1985). Apparently this species is endemic to the chain of Asir Mountains which extends to Yemen.

Identification
Aldawood & Sharaf (2011) - Head in profile with a weakly convex dorsal surface and a clearly convex ventral surface; eyes of moderate size with maximum diameter EL 0.19–0.25 × HW and with 6 ommatidia in the longest row; body colour yellow to light brownish yellow. In some individuals, head and gaster slightly but conspicuously darker than rest of body. Second halves of first and second gastral tergites with two characteristic brownish transverse bands.

A member of the Monomorium monomorium group with closest resemblance to Monomorium holothir which was described from Kenya. Both species sharing the following characters: clypeal carinae sharply developed and distinctly elevated; head sides behind eyes weakly convex; posterior margin feebly concave; in lateral view the maximum diameter of eyes clearly greater than the distance between anteriormost point of the eye and the nearest point of the mandibular articulation; body colour yellow to light brownish yellow; relatively similar body dimensions e.g. HL, HW, SI, and CI.

Monomoroium dryhimi can be easily separated from M. holothir by the following characters: eyes relatively small, their maximum diameter EL 0.19–0.25 × HW and with 6 ommatidia in the longest row, while in holothir eyes larger, their maximum diameter EL 0.30 × HW and with 8–9 ommatidia in the longest row. In M. dryhimi, the median portion of anterior clypeal margin is clearly concave, whereas it is transverse to feebly concave in holothir. Moreover, in M. dryhimi head in profile with a weakly convex dorsal surface and a clearly convex ventral surface, whereas in M. holothir, head in profile dorsoventrally flattened. Furthermore, the promesonotum in M. dryhimi has 3–4 pairs of hairs whereas in holothir the promesonotum have 8 pairs of hairs.

Distribution based on Regional Taxon Lists
Afrotropical Region: Saudi Arabia.

Habitat
Aldawood & Sharaf (2011) - The type locality is a forest called Amadan, Al Mandaq governorate, Al Bahah province, Kingdom of Saudi Arabia, with much wild vegetation including Erica arborea L, Juniperus procera Hochst. Ex Endle.and Acacia gerrardii Benth.

Castes
Known only from the worker caste.

Nomenclature

 *  dryhimi. Monomorium dryhimi Aldawood & Sharaf, 2011: 49, figs. 1-7 (w.) SAUDI ARABIA.

Worker
Holotype. TL1.84, HL 0.48, HW 0.34, SL 0.31, ML 0.46, EL 0.08, PRW 0.22, PL 0.14, PW 0.11, PPL 0.08, PPW 0.11, SI 91, CI 71.

Paratypes. TL 1.42–1.84, HL 0.42–0.49, HW 0.32–0.36, SL 0.26–0.32, ML 0.39–0.46, EL 0.07–0.08, PRW 0.19–0.24, PL 0.09–0.14, PW 0.08–0.11, PPL 0.05–0.09, PPW 0.09–0.12, SI 74–91, CI 73–83. (N=13).

Head distinctly much longer than broad with weakly convex sides and straight or feebly concave posterior margin (Fig. 1). Underside of head with several long hairs but not forming a psammophore (Fig. 2). Head in profile with a weakly convex dorsal surface and a distinctly convex ventral surface (Fig. 2). Clypeal carinae sharply developed and distinctly elevated, divergent anteriorly and reaching the anterior margin at a pair of short low triangular projecting angles (Fig. 3). The median portion of anterior clypeal margin clearly concave. Eyes oval and of moderate size (EL 0.19–0.25 × HW) with 6 ommatidia in the longest row (Figs 2, 3). With head in profile, eyes consist of a peripheral ring of ommatidia encircling two rows of ommatidia within the ring (Figs 2, 3). In lateral view, the maximum diameter of the eyes clearly greater than the distant between the anteriormost point of the eyes and the nearest point of the mandibular articulation. Frontal lobes farther apart. Antennal scapes, when laid straight back, fail to reach posterior margin (Fig. 1). Mesosoma in profile with a flat promesonotal dorsum, which slopes posteriorly to a well developed metanotal groove (Fig. 4). Metanotal crossribs relatively long and distinct (Fig. 5). Propodeal spiracles small and pinhole-like (Fig. 6). Propodeal dorsum evenly sloping, the posterior third more strongly sloping than the anterior two-thirds (Fig. 5). Petiole node high and narrowly subconical, narrowly rounded above (Fig. 7). Petiole peduncle short and stout with a distinct ventral process. Postpetiole node smaller, lower, and more broadly rounded than petiole. Petiole and postpetiole each with three pairs of long backward directed hairs. Body pilosity abundant, shorter on head dorsum. Anterior pronotal margin with two pairs of hairs, middle part of pronotum with a single pair, promesonotum with 3–4 pairs of hairs. Dorsum and declivity of propodeum each with one pair of hairs. Overall yellow to light brownish yellow. In many individuals head and gaster are slightly but conspicuously, darker than rest of body. Second halves of first and second gastral tergites with characteristic brownish transverse bands. Body smooth and shining.

Type Material
Holotype worker. SAUDI ARABIA, Al Bahah province, Amadan forest, Al Mandaq governorate, 20°12'N, 41°13'E, 1881 m.a.s.l. 19.V.2010 (M. R. Sharaf & A. S. Aldawood Leg.); King Saud Museum of Arthropods, College of Food and Agriculture Sciences, King Saud University, Riyadh, Kingdom of Saudi Arabia.

Paratypes. 27 workers, same locality and data as holotype; 1 deposited in the Muséum ďHistoire Naturelle, Geneva, Switzerland (Dr Bernhard Merz); 1 in Naturhistorisches Museum, Basel, Switzerland (Mrs. Isabelle Zürcher-Pfander); 1 in California Academy of Science (Dr Brian Fisher); 1 in World Museum Liverpool, Liverpool, U.K (Dr Guy Knight), 1 in The Natural History Museum, London (Mr. Barry Bolton); 15 workers, SAUDI ARABIA, Elqamh park, Belgershi, Al Bahah, 17.V.2010 (M. R. Sharaf & A. S. Aldawood Leg.) These paratypes are in the King Saud Museum of Arthropods, King Saud University, Riyadh, Saudi Arabia.

Etymology
This species is named in honor of Prof. Yousif N. Aldryhim, economic entomologist, Department of Plant Protection, College of Food and Agriculture Sciences, King Saud University, Kingdom of Saudi Arabia.