Hemidactylus masirahensis, Carranza & Arnold, 2012

Carranza, Salvador & Arnold, Edwin Nicholas, 2012, 3378, Zootaxa 3378, pp. 1-95 : 55-59

Hemidactylus masirahensis sp. nov.

( Figs. 3, 5, 8, 24–26, Table 1; Appendix I; Appendix III)

MorphoBank M10094 –M100230

Hemidactylus homoeolepis: Arnold, 1977: 103 (part.); Arnold, 1980: 279 (part.); Arnold, 1986: 419 (part.); Schätti and Desvoignes, 1999: 50 (part.); van der Kooij, 2000: 111 (part.); Sindaco and Jeremcenko, 2008: 115 (part.).

Holotype

BMNH1975.2080 , male from East of R.A.F. camp, North end of Masirah Island ( Oman), collected by T. D. Rogers ( MorphoBank M10094–M100115). Paratypes : BMNH1975.2081 , female, same collecting data as Holotype; BMNH1975.2082 , male from Wadi dhu Mayhi , Masirah Island ( Oman), 700 m, collected by T. D. Rogers (MorphoBank M 100116–M100137); BMNH1975.2084 , female, same data as BMNH 1975.2082 (MorphoBank M 100158–M100175); BMNH1975.2083 , female, same data as BMNH 1975.2082 (MorphoBank M 100176–M100196); IBES7710 , female from Wadi Maahdi, Masirah Island ( Oman), collected in October 2010 by S. Carranza and F. Amat (MorphoBank M 100220–M100226); ONHM3710 , female, same collecting data as IBES 7710 (MorphoBank M 100227–M100230).

Other material examined

One voucher listed in Appendix I under H. masirahensis sp. nov. and not mentioned above. Juveniles or badly preserved specimens IBES 7707, BMNH 2008.713, IBES 7661, IBES 2004 and one sample (S3412) were included in the molecular analysis only (Table 1).

Diagnosis

A small, slender, depressed Hemidactylus with a maximum recorded SVL of 42 mm. Usually with scattered weakly enlarged scales on sides of dorsum of body that become larger posteriorly especially on sacral region, tail base, and hind legs where they are raised and tuberculate; adhesive pads narrow; lamellae under the 1 st toe of pes 6; lamellae under the 4 th toe mean 10.0 (10–11); preanal pores 4 in the two males analyzed (Appendix I); expanded subcaudal scales usually extend almost to tail base. Dorsum with a pattern of irregular dark spots and streaks; tail with 8–9 dark bands that increase in intensity distally contrasting with smaller pale interstices, more distal 4–6 bands extend to ventral surface, each covering two or more whorls distally and being rather broader than interstices.

Hemidactylus masirahensis differs from H. homoeolepis in its larger adult size (SVL mean 32.2 mm, max. 45 mm, compared with mean 31.8 mm, max. 39.7 mm), greater depression of the head and body, more usual presence of dorsal tubercles on the body, lower number of preanal pores in males (4 compared with mean 5.5, 3–6), higher number of lamellae under the 1 st toe of pes (6 compared with mean 4.7, 4–5), and under the 4 th toe of pes (mean 10.0, 10–11, compared with mean 8.4, 7–11), presence of enlarged tubercles and expanded subcaudal scales usually extend almost to tail base (expanded subcaudal scales beginning some way from tail base in H. homoeolepis ), different coloring (dark bands of the tail more conspicuous and marked in H. masirahensis , especially on the underside of tail). Distinguished from H. paucituberculatus by its larger adult size (SVL mean 32.2 mm, max. 45 mm, compared with mean 32.2 mm, max. 38.4 mm), greater depression of head and body, more usual presence of dorsal tubercles on body, lower number of preanal pores in males (4 compared with 6), higher number of lamellae under the 1 st toe of pes (6 compared with mean 4.9, 4–5), and under the 4 th toe of pes (mean 10.0, 10–11, compared with mean 8.3, 7–9), different coloring (dark bands of the tail more conspicuous and marked in H. masirahensis , especially on the underside of tail).

Etymology

The species epithet “ masirahensis ” is an adjective that refers to the place where the species is found, Masirah Island off the coast of Central Oman.

Genetic and phylogenetic remarks

Hemidactylus masirahensis is monophyletic in the phylogenetic analyses of Dataset 1 ( Fig. 5F) and Dataset 3 (Appendix IIIF). According to Fig. 5 and Appendix III, it is sister to a new species described below (clade G). This topology is very well supported and is maintained even if the two endemic Hemidactylus from the island of Abd Al Kuri ( Socotra Archipelago), H. oxyrhinus and H. forbesii , are included in the analyses (Gómez-Díaz et al. in press). According to the analyses by Gómez-Díaz et al. (In press), the two endemics from Abd Al Kuri are sister taxa and branch within the “ H. homoeolepis group”, in a position between H. paucituberculatus and a monophyletic assemblage formed by H. masirahensis , clade G and H. homoeolepis . According to the results of the analysis of Dataset 2 (dates inserted in Fig. 5), H. masirahensis split from its sister taxa approximately 4.4 mya (95% HPD: 2.6–6.5). This date of origin of H. masirahensis does not differ much from the inferred date by Gómez-Díaz et al. (In press) using the same methods and calibrations and including H. oxyrhinus and H. forbesii (4.2 mya; 95% HPD: 2.4–6.3).

Uncorrected genetic distances between H. masirahensis and the other members of the “ H. homoeolepis group” (one of them described as new species below) are very high: H. masirahensis vs. H. homoeolepis 11.2% in the cytb and 8.8% in the 12S; H. masirahensis vs. H. paucituberculatus 12.9% in the cytb and 9.2% in the 12S; H. masirahensis vs. the new species from clade G ( Fig. 5, Appendix III) 14.8% in the cytb and 6% in the 12S.

The results of the nuclear networks presented in Fig. 8 are very interesting and, while all alleles of H. masirahensis for the nuclear genes c -mos and mc1r are private (not shared with its closermost taxa ( Fig. 8) or with any other species of Hemidactylus from Dataset 1 or the two endemics from Abd Al Kuri (data not shown)), all 14 alleles of H. masirahensis of the nuclear gene rag2 are shared with H. paucituberculatus . Given the fact that there is complete lineage sorting for the mtDNA (Appendix III) and in the nuclear genes c -mos and mc1r, and that no hybrids have been detected, all evidence at hand points towards ancestral polymorphism rather than ongoing interspecific gene flow.

The level of genetic variability within H. masirahensis is very low: 0.3% in the cytb and 0.1% in the 12S, and coincides with the high level of morphological homogeneity of this species (Appendix I).

Distribution

Hemidactylus masirahensis is endemic to Masirah Island, Central Oman ( Fig. 3). It has been found in very arid terrain of igneous rocks like basalt, serpentine, pyroclastics and some radiolarite almost completely devoid of vegetation ( Fig. 26). Specimens for whom data is available indicate that it has been found between 40–52 m altitude.

Habits

Hemidactylus masirahensis is a small and strictly nocturnal gecko found in dry places on rock surfaces near the ground. Hemidactylus masirahensis is sympatric with Bunopus spatalurus hajarensis Arnold, 1980 , with whom it shares the same spatial niche. Like all the other members of the “ H. homoeolepis group” it is very agile, often proceeding in a series of leaps when pursued.

Description

Up to 45 mm SVL. Head and body strongly depressed; head not especially broad posteriorly and neck well defined. In adults head length about 24–28% of SVL (mean males and females 26%), head width 64–73% of head length (mean males 68%, mean females 69%), and head height 35–49% of head length (mean males 39%, mean females 42%). Adhesive pads moderate; in adults maximum width of pad on fourth hind toe less than a third of its length.

Nostril between rostral, supranasal and two superposed postnasals, with the first upper labial scale usually also entering narrowly into its border or not. One scale separating supranasals on midline. About 11–13 scales in a straight line from postnasal to edge of orbit. No more than a few slightly enlarged scales on dorsum of head. Ear opening with its longest axis running upwards and backwards, smooth-edged, usually half of eye diameter or less. Supralabial scales mean 9.0 (8–10), infralabials mean 7.3 (7–8). Mental scale broadly triangular posteriorly, bordered by two large postmentals making contact behind it, a second pair of more lateral postmentals also present, the large postmentals contacting the first or first and second upper labials; second and more posterior lower labials bordered by more irregular and smaller enlarged scales. Gulars fine, imbricate posteriorly

Weakly enlarged flat smooth scales scattered on sides of mid-and posterior dorsum of body, becoming larger and tuberculate on sacral region and tail base, and on hind limbs where conical. Ventral scales small, but larger than dorsals and imbricate, about 30–34 in a transverse row at mid body between lateral folds (often not very apparent). The only two males available have 4 preanal pores; 2–3 cloacal tubercles on each side. Scales on upper forelimb small and imbricate, with no enlarged tubercles. Scales on front of thigh and beneath about same size as belly scales or rather smaller, larger and imbricate under tibia; scattered enlarged raised tubercles present on upper surface of both femur and tibia. Lamellae under the toes of pes: 1 st toe mean 6.0 (6), 4 th toe mean 10.0 (10–11).

Tail relatively slender with no tubercles away from base. About 7–10 small scales in longitudinal row on fourth whorl after vent. Subcaudal scales enlarged and broad, extending proximally as far as about the second whorl after the vent and starting soon after the hemipenial bulge in males.

In alcohol pale grey-buff or buff; a broad dark stripe from the nostril, through the eye, on to cheek above ear and often on to neck, where narrower and more medial; body with irregular dark spots and streaks that may form a coarse irregular reticulation; Belly pale. Tail with 8–9 dark bands that increase in intensity and contrast with pale ground color distally; more distal 4–6 bands extend to ventral surface, each covering two or more whorls distally and being rather broader than interstices. Pale areas on underside of tail may be irregularly blotched or stippled.

Distinctive features of Holotype

Adult male 42.1 mm SVL; tail complete, 50 mm long; supralabial scales 9/8, infralabials 7/8; 4 preanal pores; lamellae under the 1 st toe of pes 6/6, under the 4 th toe of pes 10/10.