Solenopsis saudiensis

At Rawdhat Khorim, Saudi Arabia, this species is rare, with only a single specimen collected by a pitfall trap in February (Sharaf et al., 2013).

Identification
Among Solenopsis species of the Arabian Peninsula, S. saudiensis is the only monomorphic species and can be immediately distinguished by its smaller size, TL 1.2–1.3 mm.

Sharaf and Aldawood (2011) - Solenopsis saudiensis is characterized by the combination of the following characters: Head in lateral view with convex dorsal and ventral surfaces; anterior clypeal margin with central pair of stout projecting teeth and a lateral pair of short, broad basal blunt teeth; eyes with two minute facets; funicular segments 2–7 about twice as wide as long; propodeum short and low, with the basal face making a continuous arc with the declivity; and petiole as long as broad with the anterior peduncle having a distinct small ventral concave surface.

Appears to be taxonomically closest to Solenopsis kochi and Solenopsis cooperi both described from Egypt. All three species share the following characters: color uniformly yellow, head smooth and shiny with very minute hair pits; mesosoma with a distinct metanotal groove; and body with abundant yellow hairs.

Solenopsis saudiensis seems taxonomically closest to S. kochi, both with the propodeum short and low, and with the basal face making a continuous arc with the declivity. Eyes consist of two minute dark facets in S. saudiensis, whereas in S. kochi, they consist of a single facet. S. saudiensis is consistently smaller; TL 1.2–1.3 versus TL 2.0; the occipital margin in S. saudiensis is shallowly concave, whereas in S. kochi it is weakly convex; the head is clearly longer than broad in S. saudiensis (CI 75), whereas it is not much longer than broad in S. kochi (CI 85). S. saudiensis has a higher scape index, SI 70–90 versus SI 73. The mesosoma length is distinctly smaller in S. saudiensis ML 0.31–0.38 versus ML 0.54 in S. kochi.

Comparing S. saudiensis with S. cooperi, both species have the posterior of the gaster darkened, the head in full-face view with nearly parallel sides; propodeum with a longitudinal impression. However, they differ in the following: S. saudiensis has eyes with two minute dark facets, while in S. cooperi they consist of a single facet. S. saudiensis has the basal face of the propodeum forming a continuous arc with the declivity, whereas in S. cooperi the faces are separated by a distinct angle. S. saudiensis has a circular propodeal spiracle, while in S. cooperi it is ovoid. S. saudiensis is consistently smaller, TL 1.2–1.3 versus TL 1.53–1.76. S. saudiensis has a smaller head with HL 0.31–0.41 and HW 0.30 versus HL 0.41–0,56, HW 0.34–0.45 in S. cooperi. S. saudiensis has a shorter scape, SL 0.21–0.27 versus SL 0.25–0.35, and SI 70-90 versus 73–77 in S. cooperi.

Superficially, S. saudiensis may be closest to Solenopsis sumara but the former always has eyes with only two minute facets whereas the later has eyes with 2–3 facets. In addition, S. saudiensis has much shorter and narrower head HW 0.30–0.31, HL 0.31–0.41 versus HW 0.46–0.51 in S. sumara.

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

Biology
Sharaf and Aldawood (2011) - One of the type series (holotype one) was found nesting at the base of a date palm tree, where many decayed falling dates were present and coexisting with several other ant species.

Our impression is that S. saudiensis seems likely to be rare in that area, where it is relatively disturbed with pesticides and other agricultural chemicals. This area is part of a small market. Only five individuals were collected there.

A large colony containing hundreds of individuals was found nesting under a rock, on a rotten used carpet and among roots of graminae plant, in a wild isolated area in Wadi Hanifa, Riyadh. Many workers of Tapinoma simrothi Krausse 1911, were also collected in the same niche attending mealybugs. Several individuals of mites were also collected. This locality is a less disturbed one and this may reflects the abundance of S. saudiensis in that area

Nomenclature

 *  saudiensis. Solenopsis saudiensis Sharaf & Aldawood, 2011: 476, figs. 1-5 (w.) SAUDI ARABIA. See also: Sharaf & Aldawood, 2012: 13.

Worker
Holotype. TL1.3, HL 0.41, HW 0.31, SL 0.27, EL 0.02, ML 0.38, PL 0.10, PW 0.10, PPL 0.10, PPW 0.13, SI 87, CI 75.

Paratypes. TL 1.2–1.3, HL 0.31–0.40, HW 0.30, SL 0.21–0.27, EL 0.02, ML 0.31–0.35, PL 0.10, PW 0.10, PPL 0.10, PPW 0.10–0.11, SI 70–90, CI 75-97 (4 measured).

Head clearly longer than broad with lateral margins slightly convex; in profile with convex dorsal and ventral surfaces; occiput weakly concave with rounded corners; and head dorsum smooth and shining with abundantly scattered minute hair pits. Mandibles armed with four reddish brown teeth, the apical tooth is the largest, the basal one is the smallest, the second and third teeth are subequal; and mandible surface glossy and brilliant with long scattered yellow hair pits. Clypeus with a strongly impressed anterior margin and sharp carinae; anterior clypeal margin with central pair of stout projecting teeth (0.02 mm); and a lateral pair of short, broad basal blunt teeth. Eyes composed of two minute dark facets (Fig. 6). Antennae of 10 segments with a well defined 2-segmented club. Scapes in full-face view falling well short of the occipital margin. Funicular segments 2–7 about twice broader than long, with abundant, decumbent long yellow hairs. Promesonotum with a smooth and uninterrupted profile. Metanotal groove weakly but distinctly impressed; and impression between mesopleuron and metapleuron faintly cross-ribbed. Propodeum with a shallow dorsal longitudinal impression. Propodeal spiracle relatively large (0.02 mm diameter) and circular (Fig. 7). Propodeum short, low with the basal face making a continuous arc with the declivity. Petiole as long as its broad in dorsal view; whereas in lateral view with a high more or less pointed node, anterior peduncle with distinct small ventral concave surface. Postpetiole about 1.3× broader than long; in profile nearly hexagonal with a distinctly convex dorsal surface. All body parts with abundant, scattered, and moderately long yellow hairs, whereas pilosity of the head dorsum is the shortest. Body uniform yellow, and gaster in some individuals slightly darker at the end.

Type Material
Type series. 5 workers (€€). (Leg. Mostafa R. Sharaf & Abdulrahman S. Aldawood). Type locality: Saudi Arabia, Riyadh, King Saud University campus, 9.VII.2009,, 24° 43’ N, 46° 37’ E, altitude 612 m; nesting under date palm tree, hand collecting by aspirator.

Holotype is deposited at the King Saud Museum of Arthropods, the Department of Plant Protection, College of Food and Agricultural Sciences, King Saud University, Riyadh, Kingdom of Saudi Arabia.

One paratype is deposited at the entomological collection, the World Museum Liverpool, Liverpool, U.K. deposited by Mr. Guy T. Knight). One paratype is deposited at Kiko Gomez collection. Two paratypes are deposited at (KSMA). All the paratypes with same data as the holotype.

Second paratype series. 117 €€ (Leg. Mostafa R. Sharaf & Abdulrahman S. Aldawood). Locality: Saudi Arabia, Riyadh, Wadi Hanifa, 24°39’ N, 46°36’ E, altitude 633 m; nesting under a rock on a rotten carpet, hand collecting by aspirator. Paratypes deposited at (KSMA).

Etymology
A patronymic name (S. saudiensis) has been selected after Kingdom of Saudi Arabia.