Cutting the Gordian Knot: Phylogenetic and ecological diversification of the Mesalina brevirostris species complex (Squamata, Lacertidae) Author Jiří Šmíd Author Jiří Moravec Author Václav Gvoždík Author Jan Štundl Author Daniel Frynta Author Petros Lymberakis Author Paschalia Kapli Author Thomas Wilms Author Andreas Schmitz Author Mohammed Shobrak Author Saeed Hosseinian Yousefkhani Author Eskandar Rastegar-Pouyani Author Aurora M. Castilla Author Johannes Els Author Werner Mayer text Zoologica Scripta 2017 2017-10-31 46 6 1 30 journal article 10.1111/zsc.12254 44b12099-59c0-4c00-b34c-c4f14d37ec56 1037920 Mesalina saudiarabica Moravec , Šmíd , Schmitz , Shobrak , Wilms – sp. n. Mesalina brevirostris – Kapli et al. (2015) Mesalina sp. – Kapli et al . ( 2015 ) Holotype . ZFMK 91912 , subadult male, Mahazat as­Sayd, Makkah Province , Saudi Arabia , 22.237 N , 41.843 E , 1000 m a.s.l. , collected in October 2006 by T. Wilms. MorphoBank pictures: M407306–M407312. Paratype . ZFMK 86583 , subadult male, Mahazat as­Sayd, near Al Muwayh , Makkah Province , Saudi Arabia , 22.395 N 41.753 E , 960 m a.s.l. , collected in October 2006 by T . Wilms. MorphoBank picture: M410851. Referred material not included in the type series. NMP 6 F 29­30 (photovoucher), adult male, observed on the type locality in October 2006 by T . Wilms. Diagnosis. A species of Mesalina and a member of the M . brevirostris species complex as revealed by the genetic analyses and characterized by the following combination of characters: (1) genetic (uncorrected) distance of 2.0% from M . brevirostris , 2.7% from M . bernoullii , and 2.8% from M . microlepis for the 12 S (after Gblocks); 2.9% from M . brevirostris , 3.3% from M . bernoullii , and 4.0% from M. microlepis for the 16S (after Gblocks); 9.5% from M. brevirostris , 7.5% from M. bernoullii , and 10.8% from M. microlepis for the cytb ; (2) low number of dorsal scales (41–42); (3) low number of collar plates (6–8); (4) low number of preanal scales (2–3); (5) low number of femoral pores in males (12–13); (6) having 1–2 large semitransparent scales in the lower eyelid window; (7) in life, dorsum light cinnamon brown with a pattern of small whitish and larger dark cinnamon spots arranged in more or less regular longitudinal rows. Most of the whitish spots are not edged with dark brown color. The dark cinnamon brown spots predominate on flanks where they form a characteristic longitudinal lateral row that continues onto the tail. Ventral side bright white, sharply contrasting with the coloration of the dorsum. Comparisons. Mesalina saudiarabica sp. n. can primarily be distinguished from other species of the complex by its genetic differentiation at both mtDNA and nDNA level. Genetic distances in the mtDNA genes are given above in the diagnosis and in Table 1 . The differentiation in the nDNA is obvious from the allele networks ( Fig. 2 ) that show that the species does not share alleles of any gene with any other species. Mesalina saudiarabica sp. n. is also geographically isolated from the rest of the complex. The nearest localities of M. bernoullii lie 680 km to the east or 860 to the north. Moreover it can be distinguished morphologically from M. microlepis by having 1–2 large semitransparent scales in the lower eyelid (several roughly equal semitransparent scales in the latter), lower number of collar plates (6–8 vs. 10–13; t ­test t = 5.01, p <0.001), lower number of dorsal scales (41–42 vs. 48– 61; t ­test t = 3.78, p <0.005), lower number of preanal scales (2–3 vs. 4; t ­test t = 8.14, p <0.001), and lower number of femoral pores in males (12–13 vs. 15–20; t ­test t = 5.12, p <0.001). The lower number of collar plates differentiates the new species also from M . bernoullii (6–8 vs. 8–13; t ­test t = 3.14, p <0.005) and M . brevirostris s. s. , although not significantly after Bonferroni correction (6–8 vs. 8–10; t ­test t = ­2.67, p <0.05) ( Tables S 4 , S 5 ). Description of the holotype . Subadult male (Fig. 4). Body slender, slightly depressed; snout short with prominent elevated nostrils, occipital shield absent, two large semitransparent scales in the lower eyelid; snout­vent length 31.0 mm, tail length 56.0 mm, head length 6.9/8.0 mm (to the anterior/posterior edge of the ear), head width 5.1 mm , head depth 3.5 mm . Upper labials (left/right) anterior the centre of eye 5/5 (smaller fifth upper labial separating the subocular from the mouth included), gulars 25, plates in collar 8, dorsals across midbody 41, ventrals across belly 12, transverse rows of ventrals 32, preanals in straight median series 3, subdigital lamellae 23/24, femoral pores 13/13. In alcohol, dorsum light brown with a pattern of small whitish and larger dark brown spots. Most of the whitish spots are not edged with dark brown color. The spots are arranged in more or less regular longitudinal rows. The dark brown spots predominate on flanks where they form a longitudinal lateral row that continues onto the tail. The lateral row of large brown spots is bordered by a dorsolateral row of small whitish spots and a narrow inconspicuous whitish ventrolateral line. Ventral side white. Variation. The paratype generally corresponds in morphology with the holotype . Apart from several minute differences in scalation described in the paragraph Diagnosis it differs also in the presence of a distinct occipital shield and the presence of only one large semitransparent scale in the lower eyelid. The paratype lacks the left hind leg and the tail. Distribution and ecology. All eight so far known localities of Mesalina saudiarabica sp. n. as well as its range of suitable conditions are located in central­western Saudi Arabia on the central plateau of the Arabian Peninsula at elevations of 900–1050 m a.s.l. The region is characterized by hot and semi­arid to arid climate with mean summer temperatures up to 30°C and mean annual precipitation of 50–100 mm with rain typically occurring between March and May (Edgell 2006; Shobrak 2011). The terrain consists mostly of flat gravel plains known as ‘regs’, occasionally intersected by dry sandy wadis and dominated by sparse vegetation of perennial grasses including Stipagrostis sp., Panicum turgidum and Lasiurus scindicus and small trees, mainly Acacia sp. (Mandaville 1990). The type locality is located in the Mahazat as­Sayd Nature Reserve, approximately 170 km E­NE of Taif. The reserve is Saudi Arabia’s only completely fenced wildlife reserve and is a reintroduction site for MacQueen’s bustard ( Chlamydotis macqueenii ), Arabian oryx ( Oryx leucoryx ) and Sand gazelles ( Gazella subgutturosa ). At the reserve, Acacia tortilis is the most common tree species, Fagonia indica and Indigofera spinosa are the most common herbs, and Panicum turgidum and Stipagrostis spp. are the prevailing grasses. Etymology. The specific epithet is derived from the name of the country where the species occurs. Proposed English name – Arabian short­nosed desert lizard.