Hemidactylus inexpectatus, Carranza & Arnold, 2012

Carranza, Salvador & Arnold, Edwin Nicholas, 2012, 3378, Zootaxa 3378, pp. 1-95 : 59-64

Hemidactylus inexpectatus sp. nov.

( Figs. 3, 5, 8, 27–29, Table 1; Appendix I; Appendix III)

MorphoBank M100233–M100346

Holotype

BMNH2008.711 , male from 2.5 km Southeast of Ar Rumayliyah , 20.3319’ N 57.78989 ’E, collected on the 29 th of October 2008 by S. Carranza, E.N. Arnold and S. Alrabiei (MorphoBank M 100257–M100280). Paratypes: BMNH2008.712 , male, same collecting data as Holotype (MorphoBank M 100233–M100256); IBES1798 , male, same collecting data as Holotype (MorphoBank M 100281–M100301); IBES7722 , male from the same locality as the Holotype, collected on the 11 th of October 2010 by S. Carranza and F. Amat (MorphoBank M 100302–M100310); IBES7700 , female, same collecting data as IBES 7722 (MorphoBank M 100311–M100315); IBES7735 , female, same collecting data as IBES 7722 (MorphoBank M 100316–M100320); ONHM3711 , female, same collecting data as IBES 7722 (MorphoBank M 100321–M100328).

Other material examined Specimen BMNH1979.467 from Hamar-an-Nafur Island, Oman (see Appendix I).

Diagnosis

A small, slender, depressed Hemidactylus growing up to 44.1 mm SVL. Low conical or weakly keeled tubercles on back and neck, arranged in 14 regular rows at mid-body, largest on lateral dorsum compared with midback and flank; larger tubercles present on hind limbs and tail; adhesive pads narrow, lamellae under the 1 st toe of pes 6, lamellae under toe 4 th toe mean 10.5 (10–11); preanal pores 4; expanded subcaudal scales extend to about 2–4 whorls from 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 pale interstices, the final 5–6 extending to the ventral surface.

Hemidactylus inexpectatus differs from H. homoeolepis by its larger adult size (SVL mean 37.5 mm, max. 44.1 mm, compared with mean 31.8 mm, max. 39.7 mm), presence of conical or weakly keeled and extensive tubercles on the body, nape hind legs and tail (generally absence of tubercles in H. homoeolepis ), 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 10.5, 10–11, compared with mean 8.4, 7–11). Distinguished from H. paucituberculatus by its larger adult size (SVL mean 37.5 mm, max. 44.1 mm, compared with mean 32.2 mm, max. 38.4 mm), larger conical or weakly keeled and more extensive tubercles on the body, nape, hind legs and tail, 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 10.5, 10–11, compared with mean 8.3, 7–9). Distinguished from H. masirahensis by having a less depressed head and body, larger conical or weakly keeled and more extensive tubercles on the body, nape, hind legs and tail, different coloring (dark bands of the tail less conspicuous and marked in H. inexpectatus , especially on adults and in the underside of the tail).

Etymology

The species epithet “ inexpectatus ” refers to the unexpected finding of this distinct new species of Hemidactylus in this area of Central Oman.

Genetic and phylogenetic remarks

Hemidactylus inexpectatus is monophyletic in the phylogenetic analyses of Dataset 1 ( Fig. 5G) and Dataset 3 (Appendix IIIG). According to Fig. 5 and Appendix III, it is sister to H. masirahensis sp. nov. 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 , H. inexpectatus and H. homoeolepis . According to the results of the analysis of Dataset 2 (dates inserted in Fig. 5), H. inexpectatus and H. masirahensis split approximately 4.4 mya (95% HPD: 2.6–6.5). This date does not differ much from the inferred date of the same split 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: 2.4–6.6).

Uncorrected genetic distances between H. inexpectatus and the other members of the “ H. homoeolepis group” are very high: H. inexpectatus vs. H. homoeolepis 13% in the cytb and 8.4% in the 12S; H. inexpectatus vs. H. paucituberculatus 13.5% in the cytb and 8.9% in the 12S; H. inexpectatus vs. H. masirahensis 14.8% in the cytb and 6% in the 12S.

The results of the nuclear networks presented in Fig. 8 and networks including all the specimens from Dataset 1 (data now shown) indicate that all alleles of H. inexpectatus for all three independent loci analyzed (c -mos, mc1r and rag2) are private (not shared with any other species included in the analyses).

The level of genetic variability within H. inexpectatus is relatively high: 1.4% in the cytb and 0.5% in the 12S, especially if one considers that all the specimens have been collected within an area of less than 0.1 km 2.

The assignation of specimen BMNH1979.467 from the offshore island of Hammar-an-Nafur to H. inexpectatus is based exclusively on morphological grounds. It will be very important to compare fresh material from this small island with the mainland specimens of H. inexpectatus (work in progress).

Distribution

Known only from a single locality in Mainland Arabia (on the coast of the Gulf of Masirah, West of Barr al Hikman, Central Oman) and from the offshore island of Hammar-an-Nafur, situated 58 km Southeast of the type locality ( Fig. 3). The altitude at the type locality is 65 m above sea level.

Habits

Very little is known about this species of Hemidactylus . On the mainland, it is active after dark on low bare rock outcrops with very little or no vegetation. The only mainland locality known for this species is in a wadi and specimens were quite close to water ( Fig. 29). 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 44.1 mm SVL. Head and body depressed; head not especially broad posteriorly and neck well defined. In adults head length about 26–29% of SVL (mean males 26% mean females 27%), head width 63–70% of head length (mean males 67%, mean females 68%), and head height 34–41% of head length (mean males 35%, mean females 40%). 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. One scale separating supranasals on midline. About 13–14 scales in a straight line from postnasal to edge of orbit. No more than a few slightly enlarged scales or tubercles 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 10.4 (9–11), infralabials scales mean 8.2 (7–9). 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 upper labials; second and more posterior lower labials bordered by more irregular and smaller enlarged scales. Gulars fine, imbricate posteriorly

Low conical or weakly keeled tubercles on back and neck, arranged in 14 regular rows at mid-body, largest on lateral back compared with mid-back and flank; larger tubercles present on hind limbs. Ventral scales small, but larger than dorsals and imbricate, about 35–42 in a transverse row at mid body between lateral folds (often not very apparent). Preanal pores in males 4; 2–3 cloacal tubercles on each side. Scales on upper forelimb small and imbricate, with a few enlarged tubercles or not. Scales on front of thigh and beneath about same size as belly scales (or rather smaller), rather larger and imbricate under tibia; 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 10.5 (10–11).

Tail relatively slender with 8 to 6 tubercles at the base, the number dropping to 4 and then to 2 about half way to tip and being absent distally. About 10–11 small scales in a longitudinal row on fourth whorl after vent. Subcaudal scales enlarged and broad, extending proximally as far as whorl 2–4 after the vent.

In alcohol pale grey; a broad dark stripe from the nostril, through the eye, on to cheek above ear; body with irregular dark spots and streaks. Belly pale. Tail with 8–9 dark bands that increase in intensity and contrast with pale ground color distally; more distal 5–6 bands extend to ventral surface, each covering the equivalent of two or more whorls distally and being equal or rather broader than interstices. Pale areas on underside of tail may be irregularly blotched or stippled.

Distinctive features of Holotype

Adult male, 44.1 mm SVL; tail intact 50 mm long; 14 rows of enlarged tubercles at mid-back; supralabial scales 10/10, infralabials 8/7; 4 preanal pores; lamellae under the 1 st toe of pes 6/6, 4 th toe of pes 11/11.