The distribution of the genus Sphecodes Latreille (Hymenoptera, Halictidae) of the Arabian Peninsula and surrounding countries with description of hitherto unknown female of S. atlanticus Warncke, 1992 and male of S. dathei Schwarz, 2010

Abstract This study summarises all available information on the bees of the genus Sphecodes in the Arabian Peninsula and surrounding countries (Israel, Jordan, and Syria). Twenty-six species are currently known from this area, while five species are newly recorded from the Arabian Peninsula: Sphecodes atlanticus Warncke, 1992 (Saudi Arabia, Yemen), S. intermedius Blüthgen, 1923 (UAE), S. nomioidis Pesenko, 1979 (UAE, Oman), S. puncticeps Thomson, 1870 (Saudi Arabia), and S. turanicus Astafurova & Proshchalykin, 2017 (Saudi Arabia). In addition, twelve species are newly recorded from Jordan, six for Syria, and four for Israel. The female of S. atlanticus Warncke, 1992 and the male of S. dathei Schwarz, 2010 are here described for the first time and a lectotype is designated for S. intermedius Blüthgen, 1923.


Introduction
The present paper is part of a series of studies dealing with the bees of the genus Sphecodes of the territory of the Palaearctic region (Warncke 1992;Bogusch and Straka 2012;Özbek et al. 2015;, 2015a, b, c, 2016a, b, 2017a, b, c, 2018Astafurova et al. , 2015Astafurova et al. , 2018a. The goal of this survey is to improve the knowledge on the taxonomy and distribution of Sphecodes in the Arabian Peninsula and surrounding countries (Israel, Jordan and Syria) (Fig. 1) as an essential foundation for advanced biogeographical investigations.
For a long time, the Arabian bee fauna has been one of the lesser sampled faunas of the world. But in recent years significant progress has been made towards a better knowledge of the bees from the Arabian Peninsula, in particular regarding the family Halictidae (Dathe 2009, Engel et al. 2013. A first contemporary inventory of the Halictidae of the Arabian Peninsula was compiled by Ebmer (2008) and Dathe (2009). Later, additional species have been described and recorded by Pesenko and Pauly (2009), Schwarz (2010), Alqarni et al. (2014), Bossert (2017), and  so that there are currently 82 species from 13 genera of family Halictidae known from this area, but the Sphecodes fauna of Arabian Peninsula is particularly under-recorded.
Probably the first information on the genus Sphecodes Latreille from the Arabian Peninsula and its adjacent lands was published by Lepeletier de Saint Fargeau (Lepeletier de Saint Fargeau and Audinet-Serville 1825), who described S. olivieri from 'Arabie'. Almost two centuries later, in his monograph on the Western Palaearctic Sphecodes, Warncke (1992) recorded several species from Israel, Syria and Lebanon ( Table 1). The list of bees of the Arabian Peninsula published by Dathe (2009) included two Sphecodes species: S. olivieri and S. longuloides Blüthgen. In the recently published third volume of the "Arthropod fauna of UAE", Schwarz (2010) described S. dathei and S. villosulus and recorded S. marginatus Hagens and S. pinguiculus Pérez from the United Arab Emirates. In total, nineteen Sphecodes species have been recorded from the Arabian Peninsula and its adjacent lands so far ( Table 1). The genus Sphecodes is not yet documented from Kuwait, Bahrain, or Iraq. Clearly this cosmopolitan genus is present in these countries and it is only a matter of time before the fauna is sampled and recorded.
Based on a comprehensive study of specimens in various collections, we here list 23 species of the genus Sphecodes, with five species recorded from the Arabian Peninsula for the first time. Additionally, twelve species are newly recorded from Jordan, six species newly recorded from Syria, and four species newly recorded from Israel. The female of S. atlanticus Warncke, 1992 and the male of S. dathei Schwarz, 2010 are here described for the first time and a lectotype is designated for S. intermedius Blüthgen, 1923.

Materials and methods
The results presented in this paper are based on 235 specimens collected in the Arabian Peninsula and surrounding territories and currently housed in the Natural History Museum (London, UK, NHMUK); the Zoological Institute, Russian Academy of Sciences (St. Petersburg, Russia, ZISP); Museum für Naturkunde der Humboldt Universität zu Berlin, Germany (ZMHB), Senckenberg Deutsches Entomologisches Institut, Müncheberg, Germany (SDEI), Oberösterreichisches Landesmuseum, Biologiezentrum, Linz, Austria (OLBL) and the private collection of Maximilian Schwarz (Ansfelden, Austria, OLBL/PCMS). The following acronyms are used for the collections where type specimens are deposited: White circle -published records (Meyer 1924;Warncke 1992;Dathe 2009;Schwarz 2010;; black circle -current data. Genus Sphecodes are not known in Kuwait, Bahrain, and Iraq.
Specimens were studied with a Leica M205A stereomicroscope and photographs taken with a combination of stereomicroscope (Olympus SZX10) and digital camera (Canon EOS70D). Final images are stacked composites using the program Helicon Focus 6. All images were post-processed for contrast and brightness using Adobe Photoshop.

Diagnosis.
This species is similar to the Trans-Palaearctic Sphecodes scabricollis Wesmael, 1835 owing to the flat genal area, the developed preoccipital lateral carina, the densely punctate head and mesoscutum, the size and shape of male antennal tyloids, and in the similar gonostylar shape. However, S. atlanticus differs from S. scabricollis by a number of characters outlined in  (Panzer, 1798), S. schenckii Hagens, 1882, S. tadschicus Blüthgen in Popov, 1935) by a short distance from top of head to upper margin of lateral ocellus (2 lateral ocellar diameters as seen in dorsal view, versus those with a long vertex where this distance is at most 2.5-3.0 diameters). Description of hitherto unknown female. Total body length 6.5-8.5 mm. Head (Fig. 5) black (except reddish mouthparts); transverse, 1.3 times as wide as long; vertex elevated, distance from top of head to upper margin of lateral ocellus ca. one lateral ocellar diameter as seen in frontal view and ca. two lateral ocellar diameters as seen in dorsal view; F1 and F2 transverse, 0.7-0.8 times as long as wide; F3 as long as wide; face with fine contiguous punctures (10-20 μm), clypeus with shiny interspaces between punctures separated by 0.1-0.5 of a puncture diameter; mandible with an inner tooth; paraocular areas and upper part of gena with dense adpressed, snow-white, plumose pubescence obscuring the integument.

Diagnosis.
The species is similar to Sphecodes crassus Thomson, 1870 owing to the wide female metafemur (strongly enlarged in the basal half ); strongly transverse female head; sparsely punctate mesoscutum in both sexes, weakly developed male antennal tyloids (usually covering less than 1/3 of ventral flagellar surfaces). The female of Sphecodes dathei differs from S. crassus by dense, apressed, snow-white, plumose pubescence obscuring integument in paraocular areas (sparse, simple pubescence not obscuring integument in S. crassus); the male differs by densely and relatively coarsely punctate T1 (in S. crassus T1 usually with a few fine punctures, rarely with relatively coarse and dense punctures). Both species have similar gonostylar shape, but S. dathei has a narrower, trapezoidal membranous portion of the gonostylus (wider, close to oval in S. crassus, Fig. 25). Description of hitherto unknown male. Total body length 5.0-6.5 mm. Head (Fig. 12) black (except reddish mouthparts and brownish antenna); weakly transverse, 1.1 times as wide as long; vertex not elevated; distance from top of head to upper margin of lateral ocellus ca. two lateral ocellar diameters as seen in dorsal view; antenna ( Fig. 13) reaches posterior margin of mesoscutum; F1 transverse, 0.6 times as long as wide; F2 long, 1.7 times as long as wide; remaining flagellomeres 1.2-1.3 times as long as wide; tyloids weakly developed (on F2-F4 covering less than 1/6 of ventral flagellar surfaces and from F5 onward covering less than 1/3); clypeus, frons, supraclypeal and paraocular areas with fine contiguous punctures (10-20 μm); ocelloocular area and gena with shiny interspaces, punctures separated by 0.5-1 a puncture diameter; face below and above the antennal toruli with dense adpressed snow-white plumose pubescence obscuring integument; gena with similar pubescence, but not obscuring integument.

Diagnosis. See
Published records. Warncke 1992: 30 (Israel). Distribution. Israel, *Jordan; North Africa, Europe (north to 63°), Russia (east to Yakutia), Turkey, Iran, Pakistan, Central Asia, Kazakhstan, Mongolia, NW China, India. Figure 11 Sphecodes intermedius Blüthgen, 1923 Fig. 11). Sphecodes lactipennis Meyer, 1925 (Synonym). Remarks. Sphecodes intermedius Blüthgen, 1923 was described from specimens of both sexes collected in "Caucas" [Caucasus] (Fig. 11). There are two specimens (female and male) in ISZP from this locality, which correspond to the original description of P. Blüthgen. One of these specimens (male) is designated here as a lectotype of S. intermedius to avoid any confusion about the status of the type specimens and to properly diagnose this species.

Diagnosis.
Refer to the diagnosis S. barbarus, above. Distribution. *Jordan; North Africa, South Europe, Russia (south of the European part), Turkey, Iran.

Diagnosis.
The female of this species as well as S. ruficrus is most close to S. pellucidus and S. ephippius owing to a densely punctate head and mesosoma, relative wide pygidial plate and impunctate T1, but differs by having a distinctly elevated vertex with the distance between vertex and upper margin of lateral ocellus at least a lateral ocellar diameter as seen in frontal view (versus 0.2-0.5). S.rubicundus differs from S. ruficrus by white pubescence of head and mesosoma (with brown setae in S. ruficrus) and a less curved basal (M) vein in hind wing. The male most closely resembles S. pesenkoi Astafurova & Proshchalykin, 2018 and S. ruficrus (Erichson, 1835) owing to a similar gonostylar shape (elongate, spoon-shaped). The male of S. rubicundus differs from S. pesenkoi by an areolate mesoscutum (versus punctures separated by 1-3 puncture diameters) and coarsely and densely punctate T1 (a few fine punctures in S. pesenkoi).
According to the phylogenetic analysis (Habermannová et al. 2013) Sphecodes rubicundus, S. ruficrus, S. pellucidus, and S. ephippius belong to the same clade. Relationship between these species also is well supported by morphological characters.
Diagnosis. The female of S. rubripes differs from S. albilabris by the pubescence of paraocular area (Fig. 6) with brown erect setae not obscuring integument (versus white plumose appressed pubescence obscuring integument usually with admixture of brownish erect setae in S. albilabris, Fig. 7). Both sexes also differ by mainly red legs, except brown coxae and trochanters, Fig. 21 (at most reddish tarsi and tibia in S. albilabris, Fig. 20). These two species also differ in phenology (males of S. rubripes were recorded in the early spring while males of S. albilabris were found in the summer) and have different hosts Straka 2012, Cross 2017 (Israel, as S. albilabris (Fabricius)).

Remarks.
Russia is mistakenly listed as within the distribution by Bogusch and Straka (2012) as well as Turkey and Armenia by Özbek et al. (2015) due to confusion with S. ruficrus rubicundus sensu Warncke (1992).

Sphecodes schenckii Hagens, 1882
Diagnosis. This species differs from other small Palaearctic species with 5-6 hamuli in the hind wing by having a unique combination of simple mandibles and the male gonocoxite dorsally with an impression. The female is closest to S. armeniacus owing to dense appressed snow-white pubescence obscuring the integument on face, a transverse head and sparsely punctate mesoscutum, but differs from this species by sparser and finer punctate ocello-ocular area (3-5 μm / 2-3 versus 5-10 μm / 1-2) and strongly transverse F3 (almost square in S. armeniacus). The male of S. villosulus recalls S. miniatus in the rectangular gonostylar shape, but clearly differs from this species by the less developed tyloids on the flagellomeres extending to approximately a half of ventral flagellar surfaces (versus those across 4/5 Distribution. United Arab Emirates, *Oman, *Saudi Arabia.

Discussion
In total, 26 species of Sphecodes are recorded from the Arabian Peninsula and surrounding lands (Israel, Jordan and Syria) ( Table 1). This is a comparable number to the Iranian fauna, but distinctly less in comparison with the adjacent fauna of Turkey, North Africa and Central Asia (Table 3).
The Sphecodes fauna of the Arabian Peninsula and surrounding lands is a complex of Mediterranean, Sahara-Gobian, endemic, and species widespread in the Palaearctic region. Eight species, namely S. alternatus, S. ephippius, S. gibbus, S. longulus, S. monilicornis, S. marginatus, S. pellucidus, and S. puncticeps are widespread from north to south of the Palaearctic region and occur in biomes ranging from forest to desert. However, two of these (S. marginatus and S. puncticeps) are recorded from the Arabian Peninsula and the remainder all are found only in Mediterranean areas.
Sphecodes majalis, S. schenckii Hagens, S. rubicundus, and S. nomioidis are steppe species, distributed in Europe, Turkey and the Caucasus to Iran. Of them, only S. nomioidis is recorded from the Arabian Peninsula.
Sphecodes olivieri, S. intermedius, S. rufiventris, and S. pinguiculus are widespread from steppe to desert in the Western Palaearctic. Of these only S. rufiventris is not recorded from the Arabian Peninsula. The distribution of Sphecodes species are given according to Özbek et al. 2015  Sphecodes barbatus, S. rubripes, and S. ruficrus are possibly purely Mediterranean species not reaching the Arabian Peninsula. In contrast, S. atlanticus turns out to be Sahara-Arabian. Sphecodes dusmeti and S. longuloides are Mediterranean-Arabian species.
Finally, two species, S. dathei and S. villosulus are endemic to the Arabian Peninsula.
Although the Arabian fauna of the genus is not fully studied it is now clear that the Arabian fauna differs from that of the Mediterranean; of 26 recorded species only six (S. olivieri, S. intermedius, S. marginatus, S. nomioidis, S. pinguiculus, and S. puncticeps) are common to both and these are all widespread in the Western Palaearctic.