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Pristurus adrarensis n. sp. Etymology The name refers to the Adrar Atar region where the species was found. This is a mountainous area in central Mauretania between 20 °N and 21 °N. Distribution At present only known from two localities in the Adrar Atar region of Mauretania: one in the eastern part of the Zerga mountains and the other 25 km north of this near the Nouatil pass between Chinguetti and Atar. Material (Figs 2–4) Holotype: male; eastern part of the Zerga mountains, about 34 km WSW of Chinguetti, Adrar Atar region, Mauretania (20 ° 19 ’ 11.6 ’’N 12 ° 40 ’ 52 ’’W; 725? m); 8 November 2005; MNHN 2006.0292. First paratype: male; same data as holotype; BMNH 2005.1603. Second paratype: female; 44km from Chinguetti on the road to Adrar, 19km before the Nouatil Pass, Adrar Atar Region, Mauretania (20 ° 32 ’ 45.2 ’’N 12 ° 17 ’ 22.2 ’’E; 703 m); 7 January 2005; BEV 5916. All specimens collected and donated by Ph. and F. GENIEZ. Diagnosis A smallbodied species of Pristurus (less than 35mm from snout to vent) with a depressed and slender habitus and pointed snout, nostril in contact with rostral scale, pupil rounded, palpebral fold above eye not projecting and without large scales on outer edge, tail laterally compressed with a dorsal crest of elongated scales that does not extend forwards beyond level of vent, a ventral fringe also present on tails of males. Premaxilla with a relatively long nasal process and a posterior ventral border forming two broad rounded projections, maxillae meeting extensively on palate behind premaxilla sometimes with a degree of interdigitation, no descending flanges on sides of frontal bone meeting on ventral midline to form a tube; anterior descending processes of frontal short; 23 presacral vertebrae and only a single pair of complete xiphisternal ribs. Most similar to P. flavipunctatus and P. gallagheri, but differing from both in smaller adult size, greater depression, more slender habitus, and more pointed snout. Males also differ from those of P. flavipunctatus in lacking a ridge of enlarged neural processes along the dorsal midline of the body, and in the dorsal crest on the tail not extending forwards on to the body, as it usually does in this species. A fragment of the mitochondrial cytochrome b gene 307 base pairs long shows a divergence of about 18 % between P. adrarensis and both P. flavipunctatus and P. gallagheri (S. Carranza and E. N. Arnold, unpublished data). Description (Table 1). Size and shape. Snout to vent length 27.4 to 31.6 mm, head length 7.2 to 8.6 mm; tail may be more than 1.24 times head plus body length, but no animals with intact tails available. Head and body markedly depressed, snout pointed, body and limbs quite slender. Scaling. Nostril in contact with rostral scale; two scales between supranasals; 34–37 scales across central midorbital region; 7–8 supralabial and 4–5 infralabial scales on each side; 3–4 postmental scales. About 104 to 108 longitudinal rows of small granular scales around midbody; dorsal body scales homogeneous, small and granular, slightly enlarged on the vertebral line but not forming a crest; gular folds present at sides of throat and also across centre in one example, ventral body scales small, flat and not distinctly imbricate. Tail laterally compressed, with a dorsal crest of large elongate pointed scales not extending forwards beyond the level of the vent; males with a smaller fringe beneath tail, made up of a repeated sequence of two single large elongated pointed scales on midline, followed by a pair of similar scales transversely arranged; female lacking a projecting ventral fringe, but scales on midline of tail large, elongate and pointed; crest and fringe also developed on regenerated portions of tail. Scales beneath tibia moderately enlarged, flat and imbricate; 22 to 26 lamellae beneath fourth toe. Colouring in life. Dorsal ground colour pale grey to greybrown. A series of 7–8 pairs of more or less distinct and confluent dark transverse dorsal markings on posterior head, neck and the body. A dark stripe on side of head, extending through the nostril and eye and on to the cheek; supralabial scales beige or reddishbrown each bearing a darker central spot. Iris reddish copper, lighter around pupil, with dark marks anteriorly and posteriorly that are confluent with the lateral head stripe; pupil large and rounded with slight angles above and below. Three longitudinal brown reddish or black lines on each flank, regularly interrupted by 5–6 creamy white spots; upper line forming an interrupted extension of the lateral head stripe. Limbs with transverse dark brownish bars (five on forelimbs and seven on hind limbs) interspersed with indistinct light spots; digits paler, brownish with darker spots. Original tail light grey to blackish with 7–8 narrow lighter vertical bars; regenerated distal sections of tail more uniform, sometimes with a lighter tip. Underparts greywhite with scattered small blackish spots, especially on throat and sides of belly. Skeletal features. Premaxilla with a relatively long nasal process, its ventral posterior margin consisting of two very rounded projections, maxillae meeting behind premaxilla, anterior descending processes of the frontal long, lateral flanges of frontal not meeting on ventral midline to form a tube, alar projection of prootic bone absent, and dorsal termination of epiterygoid bone low down on inner face of prootic. Twentythree presacral vertebrae, only a single pair of complete xiphisternal ribs, four pygal vertebrae. Distinctive features of holotype. Snout to vent length 27.4 mm, mm, head length 7.2 mm; tail 31.6mm (last 9 mm regenerated); 8 / 7 supralabials and 5 / 5 infralabials; 104 longitudinal rows of scales around midbody; 26 / 26 lamellae beneath the fourth toes. |
