Hemidactylus paucituberculatus, Carranza & Arnold, 2012

Carranza, Salvador & Arnold, Edwin Nicholas, 2012, 3378, Zootaxa 3378, pp. 1-95 : 50-54

Hemidactylus paucituberculatus sp. nov.

( Figs. 3, 5, 8, 20, 22–23, Table 1; Appendix I; Appendix III)

MorphoBank M100347–M100537

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

BMNH1977.935 , male from Khor Sawli , Salalah plain, Dhofar (South Oman), 17.04’ N 54.32 ’E WGS84, collected in October 1977 by E.N. Arnold (MorphoBank M 100347–M100363). Paratypes: BMNH1977.930 , male, same collecting data as Holotype (MorphoBank M 100364–M100380); BMNH1977.937 , male, same collecting data as Holotype (MorphoBank M 100381–M100397); BMNH1977.931 , female, same collecting data as Holotype (MorphoBank M 100416–M100431); BMNH1977.936 , female, same collecting data as Holotype (MorphoBank M 100432–M100447); BMNH1977.933 , female, same collecting data as Holotype (MorphoBank M 100448–M100464); BMNH1977.944 , female, same collecting data as Holotype (MorphoBank M 100465–M100479); BMNH1977.941 , female, same collecting data as Holotype (MorphoBank M 100480–M100496); BMNH1977.942 , female, same collecting data as Holotype (MorphoBank M 100497–M100501); ONHM3709 , female from Khor Sawli, Salalah plain, Dhofar (South Oman), collected in October 2010 by S. Carranza and F. Amat (MorphoBank M 100502–M100515); IBES7646 , female, same collecting data as ONHM 3709 (MorphoBank M 100530–M100537);

Other material examined

Five vouchers listed in Appendix I under H. paucituberculatus sp. nov. and not mentioned above. Juvenile specimens IBES 7988, IBEAO 104 IBES 7364, IBES 7336, IBES 7183 IBEAO 91, IBES 7492 and samples AO162, S3261, S3235, S7812, S7201 were included in the molecular analyses only (Table 1).

Diagnosis

A small, moderately depressed Hemidactylus with a maximum recorded SVL of 38.4 mm. Usually with flat enlarged tubercles on sides of dorsum as far forwards as mid-body that are also present on sides of dorsal tail base and on the hind legs where they are raised, and may also occur on the lower forelimb; lamellae under the 1 st finger of pes mean 4.9 (4–5); lamellae under the 4 th toe mean 8.3 (7–9); preanal pores 6 in all 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 around 8–9 dark bands that increase in intensity distally and contrast strongly with smaller pale interstices.

Hemidactylus paucituberculatus differs from neighboring populations of H. homoeolepis from South Oman in its rather larger adult size (SVL mean 32.2 mm, max. 38.4, compared with mean 30.1 mm, max. 33.4 mm), presence of enlarged tubercles and expanded subcaudal scales usually extending almost to tail base (expanded subcaudal scales beginning some way from tail base in H. homoeolepis ). Not distinguished in its maximum adult body size from populations of H. homoeolepis from the Socotra Archipelago (SVL max. 39.7 mm) or from the single specimen from Shaqra (SVL 36.4 mm). For differences from the other two new species described herein formerly part of H. homoeolepis (clades F–G in Fig. 5 and Appendix III) see below.

Etymology

The species epithet “ paucituberculatus ” is an adjective derived from Latin that refers to the presence of few tubercles on sides of dorsum as far forward as mid-body that are also present on sides of dorsal tail base and on the hind legs.

Genetic and phylogeographic remarks

Hemidactylus paucituberculatus is monophyletic in the phylogenetic analyses of Dataset 1 ( Fig. 5E) and Dataset 3 (Appendix IIIE). According to Fig. 5 and Appendix III, H. paucituberculatus is sister to a monophyletic group formed by H. homoeolepis and the two new species described below (clades F and G). However, this topology is altered when 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 Gómez-Díaz et al. in press), the two endemic Hemidactylus from Abd Al Kuri form a clade that branches between H. paucituberculatus and the monophyletic assemblage formed by clades F, G and H. homoeolepis . According to the results of the analysis of Dataset 2 (dates inserted in Fig. 5), H. paucituberculatus split from its sister clade approximately 8.2 mya (95% HPD: 5.1–11.7). This date of origin of H. paucituberculatus 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 (7.4 mya; 95% HPD: 4.6–10.8).

Uncorrected genetic distances between H. paucituberculatus and the other members of the “ H. homoeolepis group” (two of them described as new species below) are very high: H. paucituberculatus vs. H. homoeolepis 11% in the cytb and 8.5% in the 12S; H. paucituberculatus vs. the new species from clade F ( Fig. 5, Appendix III) 12.9% in the cytb and 9.2% in the 12S; H. paucituberculatus vs. the new species from clade G ( Fig. 5, Appendix III) 13.5% in the cytb and 8.9% in the 12S.

The results of the nuclear networks presented in Fig. 8 are very interesting and, while all alleles of H. paucituberculatus 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)), 18 alleles of H. paucituberculatus out of a total of 20 alleles for the nuclear gene rag2 are shared with the new species of clade G described below ( Figs. 5 and 8). Given the fact that there is complete lineage sorting for the mtDNA (Appendix III) and in the nuclear networks of c -mos and mc1r ( H. paucituberculatus even forms an independent network not connected to the other three species in mc1r; see Fig. 8), 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. paucituberculatus is very low: 0.6% in the cytb and 0.2% in the 12S, and coincides with the high level of morphological homogeneity of this species (Appendix I).

The morphological investigation of a juvenile Hemidactylus ( BMNH 1974.4051) from Al-Hasikiyah island (spelling from Google Earth), Dhofar (South Oman), suggests that it may belong to H. paucituberculatus (data not shown). Although it would make sense biogeographically, the juvenile specimen is not very well preserved and therefore it cannot be indentified with confidence. Future exploration of Al-Hasikiyah Island and the nearby islands of Al-Sawda, Al-Hallaniyah, and Al-Qibliyah should clarify the taxonomic status of the populations of Hemidactylus inhabiting this interesting archipelago.

Distribution

Hemidacytlus paucituberculatus is endemic to South Oman and is found in Central Dhofar (Salalah plain), from Salalah to Hasik ( Fig. 3). Like H. alkiyumii sp. nov., it inhabits the forested seaward (Southern) face of the Dhofar Mountains ( Fig. 1) but in this case it is restricted to the area East of Salalah. Across its distribution range it has been recorded from sea level (9 m in Khor Sawli) up to 211 m in Wadi Darbat (Table 1)

Habits

A small and strictly nocturnal gecko found in usually dry places on rock surfaces near the ground and on the beach on sandy substrates with some rocks present ( Fig. 23). In several places H. paucituberculatus is sympatric with H. alkiyumii and Ptyodactylus ; although neither of these two gecko species occupy the same microhabitat (stony ground). Hemidacytlus paucituberculatus is very agile, often proceeding in a series of leaps when pursued.

Description

Up to 38.4 mm SVL. Head and body strongly depressed; head not especially broad posteriorly and neck well defined. In adults head length about 24–29% of SVL (mean males and females 25%), head width 60–78% of head length (mean males 70%, mean females 71%), and head height 38–49% of head length (mean males 39%, mean females 41%). Adhesive pads moderate; in adults maximum width of pad on fourth hind toe around a third its length.

Nostril between rostral, supranasal and two superposed postnasals, with the first supralabial scale usually also entering narrowly into its border. One scale separating supranasals on midline. About 10–13 scales in a straight line from postnasal to edge of orbit. No enlarged scales or tubercles on head (occasionally very few weakly enlarged scales); ear opening with its longest axis running upwards and backwards, smooth-edged, usually half of eye diameter or less. Supralabial scales mean 8.9 (8–10), infralabial scales mean 7.4 (6–9). 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, supralabials; second and more posterior infralabials 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 on sacral region and tail base, and on hind limbs where they are conical. Ventral scales small, but larger than dorsals and imbricate, about 32 in a transverse row at mid body between lateral folds (often not very apparent). All males analyzed have 6 preanal pores (Appendix I); usually 2 cloacal tubercles on each side. Scales on upper forelimb small and imbricate, often some enlarged tubercles on lower limb; scattered enlarged raised tubercles present on upper surface of both femur and tibia; scales on front of thigh and beneath about same size as belly scales or rather smaller; scales rather larger and more imbricate under tibia. Lamellae under the toes of pes: 1 st toe mean 4.9 (4–5); 4 th toe mean 8.3 (7–9).

Tail relatively slender with no tubercles after whorl 6. About 7 small scales in longitudinal row on fourth whorl after vent. Subcaudal scales enlarged and broad, extending proximally almost to tail base 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; body with irregular dark spots and streaks that are often stronger anteriorly; belly pale. Tail with six or more dark bands each covering two or more whorls, being rather broader than pale intervening areas and increasing in intensity distally; ventral surface of tail pale and often irregularly blotched or stippled, the most distal four or so dorsal bands extending on to it.

Distinctive features of Holotype

Adult male 33.5 mm SVL, tail 39 mm long, broken about half way along its length with a regenerated tip. Supralabial scales 10/9, infralabials 7/7; 6 preanal pores; lamellae under the 1 st toe of pes 4/4, under the 4 th toe of pes 7/7.