Hemidactylus minutus, Vasconcelos, Raquel & Carranza, Salvador, 2014

Vasconcelos, Raquel & Carranza, Salvador, 2014, Systematics and biogeography of Hemidactylus homoeolepis Blanford, 1881 (Squamata: Gekkonidae), with the description of a new species from Arabia, Zootaxa 3835 (4), pp. 501-527 : 508-515

Hemidactylus minutus sp. nov.

( Figs. 2–5, Table 1,2)

Hemidactylus homoeolepis Arnold, 1977: 103 (part.); Arnold, 1980: 279 (part.); Arnold, 1986: 419 (part.); Schätti & Desvoignes, 1999: 50 (part.); Rösler & Wranik, 2004: 515 (part.); Sindaco & Jeremčenko, 2008: 115 (part.); van der Kooij, 2000: 111 (part.); Razzetti et al. 2011: 8 (part.); Carranza & Arnold, 2012: 47 (part.); Šmíd et al. 2013a: 7 (part.); Gardner, 2013: 134 (part.).

Holotype. NHMUK 2013.901 (sample code S7676), male, from Asylah, Oman, 21.95181N, 59.60820E WGS84, collected on the 9th October 2010 by Salvador Carranza and Fèlix Amat ( Fig. 5 B, D-E, Morphobank M999494- M9999).

Paratypes. NHMUK 2013.902 (sample code S7657), NHMUK 2013.903 (sample code S7673), ONHM 3716 (sample code S7668) and NMP 6 V 74885 (sample code S7664), All paratypes are males, except the latter one (female), and have the same collection data as the holotype (Morphobank M100008-M100011, M100012- M100017, M100000-M100007, M100039-M100043, respectively).

Referred material. Twenty specimens for genetic analyses (five of them not included in the morphological analyses; Appendix I) and 40 voucher specimens for morphological analyses (Appendix II), including the holotype and paratypes.

Etymology. The species epithet “ minutus ” is a Latin adjective that refers to the small size of this species, the smallest Hemidactylus in mainland Arabia.

Diagnosis. A small Hemidactylus characterized by the following combination of morphological characters: (1) maximum recorded snout-vent length, SVL 34.6 mm (mean 29.2 ± 3.4 mm); (2) absence of enlarged tubercles anywhere on the body; (3) expanded subcaudal scales beginning some way from tail base; (4) head narrow and low (4.2–6.7 mm in width and 2.4–3.7 mm in height); (5) relatively short snout (2.0– 2.9 mm nostril–eye); (4) 4–6 preanal pores, PAP (mean 5.8 ± 0.5); (6) four or five lamellae under the first posterior toe, LP1st (4.5 ± 0.5); (7) seven to nine, but most usually eight lamellae under the fourth posterior toe, LP4th (mean LP4th 8.0 ± 0.2); (8) weakly contrasted black and white banded pattern on the ventral part of tail.

Hemidactylus minutus sp. nov. is morphologically similar to its sister taxon H. homoeolepis but is differentiated from it by its smaller adult size (mean SVL 29.2 mm, maximum 34.6 mm, compared with mean 37.1 mm, maximum 46.8 mm; Table 2 ), higher number of PAP (80.8% with six PAP and none with three, compared with 66.7% with four PAP and 3.8% with three; Fig. 5 F versus Fig. 5 M, Table 2 ), fewer lamellae under the first toe (55.1% with four lamellae, 44.9% with five lamellae, compared with 0.0% with four lamellae, 97.5% with five lamellae and 2.5% with six lamellae), and fewer lamellae under the fourth toe (97.3% with either seven or eight lamellae, compared with 100% with nine to eleven lamellae; Fig. 5 G, versus Fig. 5 N; Table 2 ), and the less contrasted black and white banded pattern on the tail, especially on the ventral part ( Fig. 5 B, E compared with Fig. 5 I, L).

H. minutus sp. nov. H. homoeolepis Hemidactylus minutus sp. nov. differs morphologically from neighboring populations of H. paucituberculatus (formerly H. homoeolepis ) from South Oman in its rather smaller adult size (SVL mean 29.2 mm, maximum 34.6 mm, compared with mean 32.2 mm, maximum 38.4), absence of enlarged tubercles anywhere on the body (some enlarged tubercles present on the lateral sides of the second half of body), and expanded subcaudal scales beginning some way from tail base (expanded subcaudal scales usually extending almost to tail base). It differs from H. masirahensis (formerly H. homoeolepis ) endemic from Masirah Island, Oman, by its smaller adult body size (SVL mean 29.2 mm, maximum 34.6 mm, compared with mean 32.2 mm, maximum 45 mm), higher number of PAP in males (96.1% with five or six pores, compared with 100% with four pores), fewer lamellae under the first toe of pes (four or five lamellae, compared with six lamellae), and under the fourth toe of pes (from seven to nine lamellae, compared with 10-11 lamellae), absence of enlarged tubercles anywhere in the body (enlarged tubercles present on lateral sides of body), expanded subcaudal scales beginning some way from tail base (expanded subcaudal scales usually extending almost to tail base), and less contrasted black and white banded pattern on the tail, especially on the ventral part (dark bands of the tail very conspicuous and marked, especially on the underside of tail). It differs from H. inexpectatus (formerly H. homoeolepis ) endemic to Oman, by its smaller adult body size (SVL mean 29.2 mm, maximum 34.6 mm, compared with mean 37.5 mm, maximum 44.1 mm), higher number of PAP in males (96.1% with five or six pores, compared with 100% with four PAP), fewer lamellae under the first toe of pes (four or five lamellae, compared with six lamellae), and under the fourth toe of pes (from seven to nine lamellae, compared with 10–11 lamellae), absence of enlarged tubercles anywhere on the body (presence of conical or weakly keeled and extensive tubercles on the body, nape, hind legs and tail).

Figure 2 S2166 H. masirahensis

S7735

S7710 H. inexpectatus S7707

JS8 Yemen JS6 (mainland) JS5

S7657

1.71 S 7676

0.85 - 2.73 S7673

S7668

S7664

4.37

2.43 - 6.64

S3562

0.23 S 2831

0.10 - 0.39 S5305

S5189

S5306

S5353

S5154

S5106 S5373

S10575 S3422 S3308 1.35 S 3264 0.75 - 2.08 S5142 0.50 S 3347 S10574 0.22 - S3444 0.83 S 5234 S10629 S10572 S3281 S10573 S10576 S10803 S10579 S10577 S10578 H. homoeolepis S5624

S5060 24Hhomo Socotra S3289 Island S5648 0.52 S 3398 0.29 - S5430 0.82 S 5097 S3380 S10630 SPM002057 S10631 S3807 SPM001511 S3257 S10745 S3419 S3260 S5004 S3430 S3399 S3351 S4209 S3314 S10687

Figure 3 RAG1

S3260 a S5234 b S3260 b S3419 a S3419 b MC1R

S

3807

b

a

S

3257

a

AO

136

a

S

3257

b

AO

136

b

S

3314

a

S

7091

a

S

3314

b

S

7909

b

a

S

3399

a

b

S

3399

b

JS

8

b

S

3807

a

a

S

5004

a

b

AO

119

b

S

5004

b

AO

81

b

a

S

5060

a

S

7871

b

a

S

5060

b

S

7871

a

S

5353

b

S

5097

a

S

7909

a

S

7924

b

S

3398

a

S

7966

b

S

7664

a

JS

8

a

S

5097

b

S

3281

a

S

5305

a

S

7664

b

S

7668

a

AO

81

a

S

7668

b

AO

85

a

S

7673

a

AO

85

b

S

5306

b

S

7673

b

JS

75

a

S

3264

a

AO

119

a

S

7924

a

S

7657

a

S

3398

b

S

7091

b

S

7966

a

S

7657

b

JS

75

b

JS

5

a

JS

5

b

S

3264

b

S5353 a

S5353 b

AO 136 a

AO 136 b

S7871 b

S5106 a

S5106 b

S5154 a S5004 b

S5154 b

S5306 a

S2831 a S5306 b

AO 119 a S7673 a S2831 b S5373 a

AO 119 b S7673 b S3562 a S5373 b S3399 a S5097 b

AO 81 a S7676 a S3562 b S3399 b S5142 a

AO 81 b S7676 b S5189 a S3419 a S5142 b

AO 85 a S7871 a S5189 b S3422 a S5234 a

AO 85 b S7893 a S5305 a S3422 b S5234 b

JS75 a S7909 a S5305 b S3444 a S5430 a S7893 b S7091 a S7909 b S10687 b S3807 a S5430 b

S7091 b S7924 a S3257 a S3308 b S3807 b S5624 a

S7657 a S7924 b S3257 b S3314 a S4209 a S5624 b

S7657 b S7929 a S3260 a S3347 a S4209 b S5648 a

S7664 a S7929 b S3264 a S3347 b S5004 a S5648 b

S7664 b S7966 a S3264 b S3351 a S5060 a S10629 a

S7668 a S7966 b S3281 a S3351 b S5060 b S10629 b

S7668 b S3281 b S3398 a S5097 a S10687 a

S3308 a S3398 b

JS6 a

JS6 b

S3314 b c-mos

JS

75

b

S

3260

b

S

3419

b

S3264 b S5106 b

S5306 b

S5353 b

S7657 a

S7657 b S7871 b S5106 a

S7664 a S5154 a

S7664 b S5154 b

S7668 a JS5 a S5306 a

S7668 b

JS6 a

S5353 a

S

S7673

7673 a

b

S5373 a S3419 a S5648 a S S10629 10629 a b

S5373 b

S7676 a

AO 119 a S7909 a

S2831 a S

S

3419

3422 a

b

S

S

10576

5648

a

b

S7676 b S2831 b

AO 119 b S7909 b

S7924 b S3562 a

S3807 a S10576 b

AO 136 a S7924 a S3562 b S4209 a S10577 a

AO 136 b S7929 a S5305 a S4209 b S10577 b AO 81 a S7929 b S5305 b S5004 a S10579 a AO 81 b S7966 a S5189 a S5004 b S10579 b

AO 85 a S5189 b S5060 a S10630 a

S7966 b AO 85 b S5060 b S10630 b JS75 a JS5 b S5097 a S10631 a JS75 b JS6 b S5097 b S10687 a S7091 a JS8 a S3257 a S3314 a S5142 a S10687 b S7091 b JS8 b S3257 b S3314 b S5142 b S10745 a S7871 a S3260 a S3351 a S5234 a S10745 b S7893 a S3260 b S3351 b S5234 b 24Hhomo a S7893 b S3264 a S3398 a S5430 a 24Hhomo b S3281 a S3399 a S5624 a SPM001511 a S3281 b S3399 b S5624 b SPM001511 b

Legend

Oman S3422 b

Yemen (mainland) S3398 b

Yemen (Darsa Island) S5430 b

S3807 b

Yemen (Samha Island) S10631 b

Yemen ( Socotra Island)

Hemidactylus minutus sp. nov. is clearly differentiated from sympatric or geographically close populations of H. hajarensis Carranza & Arnold, 2012 , H. alkiyumii Carranza & Arnold, 2012 , H. festivus Carranza & Arnold, 2012 , and H. robustus Heyden, 1827 by its smaller adult body size and absence of enlarged tubercles anywhere on the body (all four species with maximum SVL larger than 34.6 mm, and with conical or strongly keeled and extensive tubercles on the body, nape hind legs and tail); from H. lemurinus Arnold, 1980 , and from H. flaviviridis Rüppell, 1835 by its smaller adult body size (maximum SVL larger than 34.6 mm in both species), absence of femoral pores (4–14 femoral pores on the underside of each thigh in H. flaviviridis ), and fewer lamellae under the first toe of pes (counts higher than four or five in both species).

Genetic and phylogeographic remarks. The phylogenetic analyses by Carranza & Arnold (2012), Gómez- Díaz et al. (2012), and Šmíd et al. (2013a) clearly indicate that H. minutus sp. nov. and H. homoeolepis are two genetically well differentiated sister taxa. The phylogenetic analyses performed in this study support the hypothesis that these species are reciprocally monophyletic ( Fig. 2) and present a high level of genetic divergence between them in the mitochondrial markers: p- distance (12S, cyt b, ND4) = 6.5 ± 1.1, 11.0 ± 1.5, and 11.5 ± 1.3%, respectively (Table 1). In addition, the network analyses also depict no haplotype sharing between the two species in two of the three nuclear markers and only one haplotype shared in c-mos ( Fig. 3).

Description of the holotype. NHMUK2013.901. Data on 10 morphometric, and five meristic variables (see Material and Methods) are provided in Appendix II.

FIGURE 6. General dorsal views and details of two possibly undescribed new species from mainland Arabia. A) dorsal view of the female Hemidactylus sp. 12 specimen from Shaqra, Yemen (voucher code: BMNH1953.1.6.99); B), C), D) and E) details of the head, posterior dorsal part with large tubercles, absence of preanal pores, and lamellae of the 1st and 4th toes of the same specimen, respectively; F) dorsal view of the juvenile Hemidactylus sp. 13 specimen from Khiyat, Saudi Arabia (voucher code: BMNH1992.168); G), H), I), and J) details of the head, posterior dorsal part with no tubercles, absence of preanal pores, and lamellae of the 1st and 4th toes of the same specimen, respectively.

Adult male, small (SVL 32.8 mm), body distinctly depressed ( Fig. 5 B). Right thigh muscle partially removed for tissue sample; small patch of skin missing on the dorsal surface of the right posterior limb (Morphobank M99996 -– M99997 ). Absence of enlarged tubercles; homogeneous small, granular, and generally round, not imbricate dorsal scaling on head, body, limbs, and tail ( Fig. 5 B; Morphobank M99994 ). Heterogeneous, roughly hexagonal ventral scales; gular and anteriormost ventral scales small, juxtaposed or slightly imbricate, increasing in size, height, and degree of imbrication towards the pelvic area; scales on the sides of the body with dark spot in the middle (Morphobank M99995 ). Supralabials 9/9, infralabials 8/8 (Morphobank M99998 – M99999 ). Head narrow (HW/SVL=0.2), pointed and elongated (HW/SVL=0.3). Round nostrils not protuberant, defined by rostral (entering broadly into lower nostril borders on both sides), first supralabial and three supranasals in contact with upper borders. Rostral approximately square with a median notch above. Inner supranasals in contact with rostral and separated from each other by one vertical column of two polygonal scales. Chin shield rhomboid, followed by two pairs of postmentals. Anterior postmentals large and very elongated, in wide contact behind mental, both in contact with the first and second infralabials; posterior postmentals smaller, both in contact with the second infralabials (Morphobank M99995 ). Eye relatively large (ED/HL=0.3); ear opening oval to round ( Fig. 5 D; Morphobank M99998 – M99999 ). Parietal and temporal region covered with scales of similar size and shape to others parts of the head. Lamellae under the first toe 5/5 ( Fig. 5 G); lamellae under the fourth toe 8/8 ( Fig. 5 G). Tail complete, longer than body (TL/SVL=1.1); the continuous row of enlarged tile-like subcaudal scales begins about a quarter of the tail length behind the vent ( Fig. 5 E; Morphobank M99996 ). Hemipenial swellings very obvious, with two visible elliptical openings below the vent; six pre-anal pores, PAP, in a V-shaped single row, no femoral pores or enlarged femoral scales ( Fig. 5 F; Morphobank M99997 ).

Color in life much richer than in the fixed specimen; very pale magenta-ochre, almost transparent dorsally, whiteyellowish on tail ( Fig. 5 B). Iris in life colorful, golden with brown venations and an orange central vertical stripe.

Coloration in alcohol pale grey-buff or buff; a broad dark stripe from the nostril, through the eye, on to cheek and interrupted above ear; dorsal part of body, head, and limbs with irregular dark spots and streaks; belly pale (Morphobank M99994 , M99998 – M99999 , M99995 , respectively). Tail with ten dark bands, being narrower than pale intervening areas and increasing in intensity distally; ventral surface of tail pale with the three most distal dorsal bands extending on to it (Morphobank M99996 ).

Variation. Data for 10 morphometric, and five meristic characters (see Material and Methods) for all four paratypes, NHMUK2013.902, NHMUK2013.903, NMP 6 V 74885 and ONHM3716, are provided in Appendix II. All the specimens are very similar to each other, varying slightly in size related measurements, number of supralabials, infralabials and lamellae under the fourth toe (see Appendix II). Tails of paratypes NHMUK2013.902, and NHMUK2013.903 broken at the base, and of NMP 6 V 74885, and ONHM3716 almost at the base, but pieces are preserved intact together with the specimens (e.g. Morphobank M100008, M100006). A piece of tail of paratype NHMUK2013.903 and left forearms of paratypes NMP 6 V 74885 and ONHM3716 removed for genetic analyses. Paratypes NHMUK2013.902 and NHMUK2013.903 with ventral side of tail irregularly stippled or blotched with undefined banding. Paratype ONHM3716 with regenerated tail. Paratypes NHMUK2013.902 and NHMUK2013.903 with lateral dark stripe from the nostril continuous on to neck (Morphobank M100010, M100016). Tail of paratype NMP 6 V 74885 with the four most distal dorsal bands extending on to ventral side (Morphobank M323685). Anterior right postmental of paratype NMP 6 V 74885 only in contact with first infralabial; posterior left postmental of paratype NHMUK 2013.903 in contact with the second and third infralabials (Morphobank M100040, M100013).

Main coloration very similar to the holotype, with NHMUK2013.902 and NHMUK2013.903 paratypes with darker spots and streaks.

Distribution. Distributed along the Arabian Sea coast, from northeastern Oman to extreme eastern Yemen ( Fig. 1 ; Appendix I, II). In Dhofar it is found more than 70 km inland, as far as Thumrait. Although the population of Hemidactylus “ homoeolepis ” from the Hasikaya Island in the Hallaniyat Archipelago may belong to this species, a detailed genetic and morphological analysis is needed to assess whether this population is H. minutus sp. nov., H. paucituberculatus , (also present in coastal Dhofar) or a new species. Previous reports of Hemidactylus “ homoeolepis ” from Masirah Island and from Jazirat Hamar an Nafur Island have been recently assigned to H. masirahensis and H. inexpectatus , respectively ( Carranza & Arnold 2012; pers. observ.). Hemidactylus minutus sp. nov. can be considered nearly endemic to Oman.

Natural history. The new species is a ground dwelling strictly nocturnal gecko, usually found in dry places with stony, gravely or even sandy substrates with rocky outcrops ( Fig. 5 A, C). It is abundant in many parts of its distribution range. Observations of specimens of H. minutus sp. nov. carried out by Arnold (1980) at Wadi Ayoun and Thumrait indicated that almost all the specimens (63/64) were first sighted either on the ground (38/64) or lower than 60 cm from it (25/64), and only one was found on a rock above this height. At Wadi Sayq, eighteen individuals reported also by Arnold (1980) were at heights of between 50 cm and 2 m on rock faces, but this may have been because the ground here was covered by dense vegetation following the monsoon. Hemidacytlus minutus sp. nov. is very agile, often proceeding in a series of leaps when pursued. Gravid females, each carrying a single egg, have been recorded in late September at Khawr Sawli ( Arnold 1980).

Conservation status. Not evaluated.

Figures

FIGURE 1. Distribution map of the samples used in this study. Color dots indicate specimens included in the molecular analyses and listed in Appendix I. Color stars indicate voucher specimens examined and listed in Appendix II, most of which were included in the morphological analyses. The specimens’ location colors match the colors used in the following figures. Localities of the undescribed specimens Hemidactylus sp. 12 (BMNH 1953.1.6.99 from Shaqra, Yemen) and Hemidactylus sp. 13 (BMNH 1992.168 from Khiyat, Saudi Arabia) are also shown in the map.

FIGURE 5. Type localities, general dorsal views and details of Hemidactylus minutus sp. nov. from mainland Arabia and H. homoeolepis from Socotra. A) and C) type locality (Asylah, Oman) of H. minutus sp. nov.; B) dorsal view of Hemidactylus minutus sp. nov. holotype (voucher code: NHMUK 2013.901; sample code: S 7676); D), E), F) and G) details of the head, tail underside pattern, preanal pores, and lamellae of the 1 st and 4 th toes of the holotype; H) dorsal view of one of the two H. homoeolepis syntypes (voucher code: original BMNH 81.7.22.6 and after the II World War BMNH 1946.9.6.99), and I) of an unvouchered specimen (photograph by Edoardo Razzetti); J) habitat type of H. homoeolepis, generally dry places with rocky substrate; K), M) and N) details of the head, preanal pores, and lamellae of the 1 st and 4 th toes of the syntype, respectively; L) detail of the pattern of underside the tail of and unvouchered specimen.

Tables

TABLE 2. Mean, standard deviation (SD) and range of the morphological variables examined for H. minutus sp. nov. from mainland Arabia and H. homoeolepis from Socotra.

Variable code	mean ± SD	range	mean ± SD	range
Snot-vent length SVL	29.2 ± 3.4	20.5–34.6	37.1 ± 4.0	29.2–46.8
Trunk length TRL	12.48 ± 1.7	8.8–14.9	15.9 ± 2.0	12.1–19.8
Tail length TL	28.5 ± 4.4	23.5–36.0	32.1 ± 8.9	17.0–44.0
Head length HL	7.6 ± 0.8	6.2–9.6	9.4 ± 1.1	7.4–12.0
Head width HW	5.2 ± 0.6	4.2–6.7	6.9 ± 0.9	5.3–9.0
Head height HH	3.0 ± 0.4	2.4–3.7	4.2 ± 0.5	3.4–5.0
Orbital diameter OD	1.9 ± 0.2	1.4–2.3	2.5 ± 0.3	1.7–3.1
Nostril–eye distance NE	2.4 ± 0.2	2.0–2.9	3.2 ± 0.4	2.7–3.9
Anterior interorbital distance IO1	2.6 ± 0.4	2.0–3.5	3.6 ± 0.4	2.9–4.5
Posterior interorbital distance IO2	3.6 ± 0.4	2.8–4.5	4.8 ± 0.7	3.3–6.0
Preanal pores PAP	5.8 ± 0.5	4.0–6.0	4.3 ± 0.9	3.0–6.0
Mean number of supra-labial scales SL	9.2 ± 0.5	8.0–10.0	8.7 ± 0.7	8.0–10.5
Mean number of infra-labial scales IL	7.6 ± 0.5	6.5–8.5	7.9 ± 0.5	6.0–9.0
Mean number of lamellae under the LP1st first toe	4.5 ± 0.5	4.0–5.0	5.0 ± 0.2	5.0–6.0
Mean number of lamellae under the LP4th fourth toe	8.0 ± 0.2	7.5–9.0	9.9 ± 0.5	9.0–11.0