Scarabaeus (Scarabaeus) aegyptiacus Stolfa, 1938 was described as S. transcaspicus aegyptiacus Stolfa, 1938 based on a single specimen (holotype by monotypy) from lower Egypt (“Basso Egitto”, loc. typ.), without more accuracy (Stolfa, 1938; Ziani & Gudenzi, 2002). Since its description, it has either been indifferently ignored (Strassen, 1967; Cambefort et al., 1979; Kavakov, 1980, 2006), considered to be synonymous with Scarabaeus sacer Linnaeus, 1758 and Scarabaeus sacer acuticollis (Motschulsky, 1849) (Janssens, 1941; Balthasar, 1963), or discussed as a North African subspecies of Scarabaeus transcaspicus Stolfa, 1938 (Schatzmayr, 1946; Baraud, 1985, 1987; Zídek & Pokorný, 2008), whose nominal subspecies is widely distributed through the Middle East and Central Asia (Afghanistan, northeastern Iran, Kazakhstan, Tajikistan, Turkmenistan and Uzbekistan; see Zídek & Pokorný, 2004; Löbl et al., 2006).

Ziani & Gudenzi (2002) contemplate Scarabaeus (Scarabaeus) aegyptiacus Stolfa, 1938 as a separate, independent species from S. transcaspicus based on weak and scarce traits (pronotal punctuation, simply on disc and basal edge, wider smooth pronotal areas and reddish color of male metatibial brush), but, especially, due to the evident geographical segregation between both taxa (there is a vast geographic gap). Nevertheless, according to Zídek & Pokorný (2004) the evidence for species status is very weak and argue that the character concerning metatibial brush coloration is variable in Asiatic populations of S. transcaspicus transcaspicus (reddish, gray or black), which discredits the taxonomic value of this trait (Zídek & Pokorný, 2008). Löbl et al. (2006) and more recently Ziani & Gudenzi (2012) keep on considering it a valid species.

Scarabaeus aegyptiacus has been cited from Morocco, Algeria, Tunisia, Lybia, Egypt (Schatzmayr, 1946; Baraud, 1985, 1987; Ziani & Gudenzi, 2002; Zídek & Pokorný, 2004, 2008; Löbl et al., 2006) and Saudi Arabia (Ziani & Gudenzi, 2012). Even though it was described from Egypt, Alfieri (1976) did not record it in his catalogue. Baraud (1985, 1987) mentioned that, in North Africa, it is less common than S. sacer, with which occasionally it could have been confused.

Its widespread extent of occurrence (sensu IUCN, 2001; EOO: 1.720.927 km², including the new location) contrasts with its reduced area of occupancy (AOO: 900 km²; EOO and AOO enabled with Geospatial Conservation Assessments Tool, available at: http://geocat.kew.org; see Bachman et al., 2011), for it is only known from ten localities (nine 10 x10 km cells; Table 1; Fig. 1), mostly very spaced apart and with apparently fragmented populations. In the case of Morocco, Ziani & Gudenzi (2002, 2012) were the first to indicate its existence in that country, without specifying location (“Morocco, V.1986”, 1 specimen studied); subsequently, Labrique & Chavanon (2008) recorded it from two very close stations in Bouârfa and Chavanon & François (2014) provided a new locality, Maatarka, all of them in the arid eastern Morocco, nearby to the border with Algeria (Fig. 1).

During a recent field survey in southwestern Morocco, we found some individuals of S. aegyptiacus 10 km south from Msied (= El Messied), in the province of Tan-Tan (administrative region of Guelmin-Es-Semara). This is the first record from Atlantic Sahara and the most southwestern one. Likewise, the known geographic distribution of the species is considerably extended, for the westernmost record until now was located in Maatarka (Morocco), about 1.000 km northeastward by air (Fig. 1). Specimens were identified according to morphological features pointed out by Baraud (1985, 1987), Ziani & Gudenzi (2002) and Zídek & Pokorný (2008), and confirmed with the examination of male genitalia.

Material examined: 2 males collected and 5 individuals observed, 27º55’13’’N – 10º49’59’’O, 10.1 km southern of Msied, Tan-Tan province, Guelmin-Es-Semara Region, Morocco, 23^rd March, 2016, L. García-Cardenete & S. Yubero leg.

The new location is found in the western foothills of the Jebel Ouarkziz mountain range, on the transition area between the natural regions namely Lower Draa and Tarfaya (e.g. Thévenot et al., 2003). The bioclimate of the area is higher hyper-arid (sensu Le Houérou, 1989, 1995), with some atlantic influence (annual average rainfall at Msied: 82 mm). The habitat is a rocky steppe (hamada), crossed by dry seasonal streams or “wadis” with a sandy bed. The vegetation has very low coverage with sparse ligneous steppe plants, among which stand widely dispersed acacia trees [Acacia tortilis (Forsk.) Hayne and Acacia ehrenbergiana Hayne] and xeric scrub mainly of Lycium intrincatum Boiss., Launaea arborescens (Batt.) Murb., Zygophyllum gaetulum Emb. et Maire, Calotropis procera (Aiton) W.T. Aiton and Farsetia occidentalis B.L. Burtt. The livestock of the region, whose droppings or excrements constitute the main food resource for S. aegyptiacus, consists of nomadic herds of goats and dromedaries.

The specimens were found alive in a water cistern, during surveys in the framework of a study to determine the impact of these infrastructures on communities of terrestrial vertebrates in arid environments from southern Morocco. Water cisterns or reservoirs that retain the runoff water from torrential rain and flash floods (called matfiya and al jiba in the local language) have become deadly traps for many animals, especially reptiles and amphibians (García-Cardenete et al., 2014), as well as numerous epigean beetles and other terrestrial arthropods (L. García-Cardenete and S. Yubero, pers. obs. 2014-2016), acting as giant pit-fall traps, whose effect on these invertebrate communities has not yet been evaluated.

The specimens studied of the southwestern Moroccan population (Fig. 2) are longer (33-36.5 mm) than those indicated by Ziani & Gudenzi (2002; 31 mm) and show the characteristic traits of S. aegyptiacus: front tubercles slightly elevated and separated; simple pronotal punctures on the disc and basal edge; wide smooth areas on the posterior half of pronotum; meso and metatibial hairs reddish brown, including the brush along the edge of metatibiae (males); weak V-shaped carina on ventral side of third protibial tooth does not reach anywhere near central longitudinal carina; margins of elytra parallel; spatulate apex of metatibiae as long as apical spurs (Ziani & Gudenzi, 2002; Zídek & Pokorný, 2008) and parameres of the aedeagus similar to those illustrated by Ziani & Gudenzi (2002: 153).

In view of the new Moroccan location, the older records from Mateu (1950) for S. sacer from the northwestern Saharan region (Saguiat el Hamra), some 150 km south from Msied, could correspond to S. aegyptiacus, since both species are morphologically very similar, and according to Kocher (1958) the first one occupies the whole of Morocco with a southern limit in the Saharan regions. In accordance with known locations (Table 1), S. aegyptiacus is distributed throughout the northern fringe of the Sahara (nine locations, including High Plateaux from eastern Morocco) to the central region of the Arabian desert (one location), in areas with a bioclimate ranging from upper eremic to middle arid (according to Le Houérou classification, 1989, 1995), in an altitudinal range from sea level to 1.290 m. It is very possible that the apparent fragmentation of their populations may be due more to defects or lack of specific sampling and confusion with other Scarabaeus species (especially with S. sacer, the morphologically closest North African species; Baraud, 1985; Ziani & Gudenzi, 2002; Zídek & Pokorný, 2004, 2008) than to a real absence of the species in those broad northern Saharan areas.