Gekko hulk, Grismer & del Pinto & Quah & Anuar & Cota & McGuire & Iskandar & Wood Jr & Grismer, 2022

Grismer, L. Lee, del Pinto, Lelani, Quah, Evan S. H., Anuar, Shahrul, Cota, Michael, McGuire, Jimmy A., Iskandar, Djoko T., Wood Jr, Perry L. & Grismer, Jesse L., 2022, Phylogenetic and multivariate analyses of Gekko smithii Gray, 1842 recover a new species from Peninsular Malaysia and support the resurrection of G. albomaculatus (Giebel, 1861) from Sumatra, Vertebrate Zoology 72, pp. 47-80 : 47

Gekko hulk sp. nov.

Figures 7 , 11 , 12 , 13

Gecko Stentor : Boulenger 1889:184 (in part), 1912:51 (in part); Müller 1895:832 (in part); Flower 1896:867 (in part), 1899:634 (in part); Laidlow 1901:306; de Rooij 1915:57 (in part)

Gekko smithi : Smith 1935:113 (in part); Taylor 1963:803 (in part); Jeffery 1997:145

Gekko smithii : Grossmann and Ulber 1990:9 (in part); Kluge 1991:10 (in part); Ota et al. 1991:147 (in part); Manthey and Grossmann 1997:234 (in part); Lim and Lim 1999: 143; Hien et al. 2001:14; Grismer et al. 2004:252; Grismer et al. 2002:27; Grismer et al. 2004:252; Grossmann and Tillack 2004:45, 2005:58; Grismer et al. 2006:160; Grismer 2011a:127 (in part), 2011b:469 (in part); Shahrudin 2013:83 (in part)

Gekko albofasciolatus : Kluge 1991:10 (in part)

Gekko albomaculatus : Kluge 1991:10 (in part)

Gekko sp. Rösler et al. 2011:11

Gekko (Gekko) smithii : Wood et al. 2020a:7 (in part)

Gekko Non-technical books, field guides, and pockets guides are not listed

Holotype.

Adult male LSUHC 6284 from the Tekek-Juara trail on Pulau Tioman, Pahang, Peninsular Malaysia (2.821021°N 104.179596°E; 462 m) collected by Jesse L. Grismer, Perry L. Wood, Jr., and L. Lee Grismer on 2 July 2004.

Paratypes.

All paratypes are from Peninsular Malaysia and were collected by various personnel from La Sierra University, Universiti Sains Malaysia, Universiti Kabangsaan Malaysia, and the Department of Wildlife and National Parks Malaysia. Adult female LSUHC 6283 bears the same data as the holotype. Adult females LSUHC 5152 and 5399 from the upper Tekek-Juara trail on Pulau Tioman, Pahang (2.821021°N 104.179596°E; 462 m) collected on 3 March 2003. Adult female LSUHC 7026 from Pulau Tulai, Johor (2.909920°N 104.105315°E; 11 m) collected on 14 September 2004. Adult male LSUHC 5062 from Pulau Tulai, Johor (2.909920°N 104.105315°E; 11 m) collected on 17 August 2002. Adult male LSUHC 7648 from Endau-Rompin, Peta, Visitor center, Johor (2.530818°N 103.414191°E; 42 m) collected on 25 August 2005 by Perry L. Wood, Jr., Kin Onn Chan, and L. Lee Grismer. Adult female LSUHC 7649 and 7651 from Endau-Rompin, Peta, Visitor center, Johor (2.530818°N 103.414191°E; 42 m) collected on 25 August 2005 by Perry L. Wood, Jr., Kin Onn Chan, and L. Lee Grismer. Adult female LSUHC 7694 from Endau-Rompin, Peta, Sungai Semawak, Johor (2.529150°N 103.401173°E; 36 m) collected on 29 August 2005 by Perry L. Wood, Jr., Kin Onn Chan, Norhayati Ahmad, and L. Lee Grismer. Juvenile female LSUHC 10585 from Gunung Ledang, Johor (2.529150°N 103.401173°E; 36 m) collected on 31 May 2008, collector unknown 2008. Juvenile female LSUHC 9959 from Gunung Lambak, (2.029934°N 103.353323°E; 255 m). Juvenile male ZRC 2.6014 from FRIM, Pasoh, Negeri Sembian (2.968545°N 102.297043°E; 255 m) collected on 27 November 2008. Adult male LSUHC 1197 from Sungai Bubu, Terengganu (4.997105°N 102.953106°E; 174 m) collected on 1 September 2009 by L. Lee Grismer and Kin Onn Chan.

Diagnosis.

Gekko hulk sp. nov. can be separated from all other species of Gekko in the G. smithii species complex by having the combination of a maximum SVL of 161.3 mm, 10-15 supralabials, 9-13 infralabilas, 3-5 internarial scales, 13-24 frontal scales, 4-8 chin scales, 84-110 midbody scales, 16-21 paravertebral tubercles, 9-11 longitudinal rows of tubercles, 22-28 ventral scales, 14-19 1st toe subdigital lamellae, 18-24 4th toe lamellae; 6-13 precolacal pores in males (absent in females); subcaudals enlarged; thin, white nuchal band at base of occiput composed of closely spaced spots; thin dark nuchal band absent or faded and never contacting eyes; small white ocelli confined to dorsal tubercles or their anterior margin in six or seven transverse rows; and no thick dark reticulum on body (Tables 9 , 10 ).

Description of holotype (Fig. 12 ).

Adult male SVL 147.5 mm; head moderate in length (HL/SVL 0.28), width (HW/HL 0.65), somewhat flattened, distinct from neck, triangular in dorsal profile; lores concave slightly anteriorly, weakly inflated posteriorly; prefrontal region concave; canthus rostralis rounded; snout elongate (SE/HL 0.41), rounded in dorsal profile; eye large (OD/HL 0.26), pupil vertical, margins crenulated; ear opening elliptical, obliquely oriented, moderate in size; eye to ear distance slightly less than diameter of eye; rostral rectangular, bordered posteriorly by large left and right supranasals and smaller azygous postrostral, bordered laterally by first supralabials; external nares seated anteriorly in nasal scale bordered anteriorly by rostral, dorsally by large anterior and smaller posterior supranasals, posteriorly by three small postnasals, ventrally by first and second supralabials; five internasals; 12 (R,L) rectangular supralabials, first supralabial slightly larger than second; 12(R) 10(L) infralabials tapering smoothly to angle of jaw; scales of rostrum and lores flat, larger than flat scales on top of head and occiput; scales of occiput intermixed with distinct, small tubercles; superciliaries elongate, largest dorsally; mental not enlarged, subtriangular, bordered laterally by first infralabials and posteriorly by left and right trapezoidal postmentals contacting medially for 60% of their length posterior to mental; one row of slightly enlarged, elongate chin scales extending posteriorly to fifth (R) and sixth (L) infralabial; gular and throat scales small, flat, juxtaposed, grading posteriorly into larger, smooth, imbricate, pectoral scales which grade into larger ventral scales.

Body slightly flattened, relatively long (AG/SVL 0.51) with well-defined ventrolateral folds; dorsal scales small, flat, juxtaposed, interspersed with larger, smooth subconical, regularly arranged tubercles; 110 longitudinal rows of scales at midbody; 17 paravertebral tubercles, those at midbody surrounded by 9-12 smaller scales; 10 longitudinal rows of tubercles at midbody; body tubercles extend from occiput onto base of tail forming transverse rows, terminating near end of original tail; smaller tubercles in temporal and postocular regions; 25 longitudinal rows of flat, imbricate, ventral scales much larger than dorsal scales between body folds; and eight large, pore-bearing, precloacal scales.

Forelimbs moderately robust, relatively short (FL/SVL 0.13); large, imbricate scales of upper arm and anterior surface of forearm larger than those on posterior surface which are interspersed with large tubercles; palmar scales flat, subimbricate; digits well-developed, inflected at penultimate interphalangeal joints, arising from digital pad; subdigital lamellae wide, transversely expanded forming digital pad; claws well-developed, claw base sheathed by a dorsal and lateral scale; digit I clawless; hind limbs more robust than forelimbs, moderate in length (CL/SVL 0.16), covered anteriorly by large, flat, imbricate scales, dorsally and posteriorly by much smaller flat, juxtaposed scales interspersed with large, subconical tubercles; ventral scales of hind limbs large, flat, imbricate, abruptly contacting small postfemoral scales; femoral pores absent; plantar scales flat, subimbricate; digits well-developed, inflected at penultimate interphalangeal joints, arising from digital pad; distal subdigital lamellae wide, transversely expanded forming digital pad; 15 transverse lamellae beneath digit I, 19 transverse lamellae beneath digit IV; claws well-developed, claw base sheathed by a dorsal and lateral scale; digit I clawless; small amount of webbing between digits I-IV.

Tail original, 139.0 mm in length, tapering to a point; dorsal scales flat, square, bearing transverse rows of six large, subconical tubercles; tubercle rows separated by six or seven transverse rows of dorsal scales; large, paired, median, transversely expanded subcaudal scales; and base of tail bearing hemipenal swellings, each with two conical postcloacal tubercles.

Color pattern (Figs 11, 12).

Ground color of all dorsal surfaces yellowish-brown bearing slightly darker faint mottling; top of head bearing small white spots and dark-colored, diffuse Y-marking; thin white nuchal band composed of closely spaced spots extends from one ear opening to other, edged anteriorly by faint, dark-colored nuchal band running between postocular regions; incomplete series of obliquely aligned, small white spots immediately anterior to forelimb insertions parallel the white nuchal spots; series of five rows of transversely arranged, widely separated, small white spots between limb insertions, another between hind limb insertions; white spots on body generally confined to tubercles or border them anteriorly; limbs bearing incomplete, thin white bands; white spots on base of each digit and one or two more on each digit; venter beige, mottled with faint dark-colored markings, weakest in gular region, most dense in subcaudal region; and center of iris gold, transitioning distally to green then turquoise.

Variation (Figs 7, 8).

Color pattern variation in Gekko hulk sp. nov. is not as extensive as that in G. smithii . The hue and intensity of the ground color changes from day to night and is generally lighter and less bold during evening hours. The description here is of the daytime coloration. The dorsal ground color in life can be dark brownish green, light-green, tan or yellowish brown. There are no thick, dark-colored reticulations on the dorsum although some specimens have faint, brown markings. The white dorsal spots are small and typically confined to the tubercles although in some specimens they may border the tubercles anteriorly or both. The light-colored caudal bands can vary in both width and boldness. In one specimen from Pulau Tioman (LSUHC 5152; Fig. 8K ), the white nuchal spots form a solid band as in G. albomaculatus . The color pattern of hatchlings and juveniles is more boldly marked. Variation in morphology is presented in Tables 11 and 12 .

Distribution.

Gekko hulk sp. nov. ranges from at least the southeastern corner of southernmost Thailand in the Hala-Bala Wildlife Sanctuary, Narathiwat Province, southward east of the Banjaran Titiwangsa through Peninsular Malaysia to Singapore. It approaches the west coast of Peninsular Malaysia south the Banjaran Titiwangsa at Gunung Ledang, Johor. It is known from the east coast islands of Perhentian Besar and Redang, Terengganu in the north and from the islands of Tulai and Jahat, Johor and Tioman, Pahang in the south (Figs 1 , 7 ).

Contact zone with Gekko smithii (Fig. 7).

As noted above, the DFA placed THNHM 01841 from the Hala-Bala Wildlife Sanctuary, Waeng District, Narathiwat, Province, Thailand in Gekko cf. albomaculatus with a 79.5% PsP and in G. smithii with a 20.2% PsP. The DAPC placed it in G. smithii with a 100% PsP. THNHM 01841 bears the color pattern of the northern populations of G. smithii having white ocelli surrounding the tubercles (e.g. Figs 7I , 8G ) although the ocellei are somewhat reduced in width (Fig. 13 ). However, photographs of two other specimens from the Hala-Bala Wildlife Sanctuary that were not examined, have the typical G. hulk sp. nov. color pattern with small white spots generally restricted to the tubercles (LSUDPC 12880 and 12953; Figs 7J and 8J , respectively). Examination of a specimen of G. smithii from Pa Phru Sirinthorn Research Station, Su-ngai Kolok District, Narathiwat (THNHM 01844) and a photograph of another specimen of G. smithii from Waeng, Narathiwat (LSUDPC 12877, Fig. 7I ) approximately 32 km and 13 km to the north of the Hala-Bala Wildlife Sanctuary, respectively, also have the typical northern G. smithii color pattern. Both the DFA and DAPC placed THNHM 01844 in G. smithii with a 100% PsP. These data indicate the G. smithii and G. hulk sp. nov. are very likely to be sympatric in the Hala-Bala Wildlife Sanctuary and that the color pattern of THNMH 01841 may be the result of hybridization. A genomic data set is currently being developed to further investigate this contact zone.

Etymology.

The specific epithet " Gekko hulk " is a noun in apposition in reference to ‘‘ The Incredible Hulk’’, who is a fictional character and superhero created by Stan Lee and artist Jack Kirby in 1962 and appears in the Marvel Comics publications. When angry, The Incredible Hulk becomes a large, green-skinned, muscular beast possessing great physical strength and a very aggressive temperament-all characteristics of Gekko hulk sp. nov.

Comparisons.

Wood et al. (2020a) erected the subgenus Gekko (Gekko) based on the phylogenetic relationships of the holotype of G. hulk sp. nov. (LSUHC 6284) and its inferred close relationship to the generotype species G. gecko ( Rösler et al. 2011) in order to contain the species G. albofasciolatus ; G. gecko (Linnaeus, 1758); G. nutaphandi Bauer, Sumontha, and Pauwels, 2008; G. reevesii (Gray, 1831); G. siamensis Grossmann and Ulber, 1990; G. smithii s.s.; and G. verreauxi Tytler, 1864. To this we add G. albomaculatus , G. hulk sp. nov., and G. stoliczkai . Although several authors have used dorsal ground color as a diagnostic character (e.g. Rösler et al. 2011; Otal et. al. 1991), it is too variable in all species to be of diagnostic significance (see above). Chandramouli et al. (2021) noted several statistically significant differences in meristic and morphometric characters between G. smithii s.l. and G. stoliczkai . No data or formal analysis has ever been forwarded to argue that Gekko taylori Ota and Nabhitabhata, 1991 is a junior synonym of G. siamensis . Thus, the former remains in G. (Gekko) pending the outcome of current investigations (Grismer unpubl).

Gekko hulk sp. nov. can be separated from other species of the subgenus G. (Gekko) by a number of discrete characters (Table 10 ). Gekko hulk sp. nov. differs from G. gecko and G. smithii by having a much smaller maximum SVL (161.3 versus 185.0 and 191.0, respectively) and from G. nutaphandi (SVL 117.0) and G. stoliczkai (SVL 128.4) by having a larger maximum SVL. It differs from G. verreauxi by having the rostral scale in contact with the external nares as opposed to them being separated by a small scale. Gekko hulk sp. nov. differs from G. gecko and G. reevesi by having occipital scales and those on the top of the head smaller than the scales on the rostrum as opposed to them being the same size and having enlarged versus small subcaudal scales. It differs from G. reevesi by having 9-11 versus 12-18 longitudinal rows of dorsal tubercles. Male G. hulk sp. nov. differ from G. albofasciolatus , G. nutaphandi , G. reevesi , G. smithii , and G. stoliczkai in having fewer precloacal pores (6-13) as opposed to 13-15, 17-22, 13-20, 13-15, and 13-15, respectively. Gekko hulk sp. nov. has a turquoise/green iris which separates it from G. gecko and G. reevesi that have a gold/copper to olive/brown iris, from G. nutaphandi which has a bright-red iris, and from G. verreauxi which has a golden iris. It differs from G. albomaculatus by not having a thin, white, solid nuchal band (except for one specimen from Pulau Tioman). Gekko hulk sp. nov. differs from G. albofasciolatus by having as opposed to lacking a white nuchal band. Gekko hulk sp. nov. differs from G. smithii in that the small white dorsal spots, if not confined to the tubercles, tend to border them anteriorly, whereas in G. smithii , the dorsal tubercles are surrounded by a large white ocellus in northern populations and the smaller ocelli in the southern populations only tend to border the tubercles posteriorly. Gekko hulk sp. nov. has a number of significantly different mean meristic and morphometric values as well as significantly different morphospatial placement that separate it from G. albofaciolatus , G. albomaculatus , and G. smithii (Figs 3 - 6 ; Tables 6 - 9 ).

Natural history.

Much like other species of Gekko (Gekko) , G. hulk sp. nov. is an arboreal nocturnal species that is well-established in all types of primary and secondary forests as well as buildings on forest edges. We observed lizards 3-4 m above the ground on the trunks of large trees on Gunung Tebu (Fig. 14 ) and heard males calling in the afternoon. On Pulau Tioman, we observed individuals 4-5 m above the ground on tree trunks, in tree cavities, and on cement light poles. On Pulau Tulai, lizards were seen on trees during the day but collected off the metal stair railing at night. On Perhentian Besar, geckos occur is high densities and are more common on granite boulders where they take refuge between boulders and in rock cracks. Lizards are far less common on tree trunks. Grismer (2011b) reports finding eggs attached to the undersides of boulders on Pulau Perhentian Besar during September and a gravid female was collected during July on Pulau Tioman.

Figures

Figure 1. Distribution of the species of the Gekko smithii complex from throughout their respective Sundaic land masses. Circles denote the localities of specimens that were both examined first hand and are represented in the phylogeny (Fig. 2). Stars denote type localities. Squares denote localities of specimens or photographs examined here or verified from other publications as well as vouchered samples in the literature. Localities from non-peer reviewed literature or unverifiable online data were not included.

Figure 3. A, PCA and B, DAPC of morphometric data of the species of the Gekko smithii complex. C. Bar plots of PCA loading scores of PC 1 - PC 3.

Figure 6. A. Box plots of meristic characters showing the range, mean (blue dot), and 50 % quartile (rectangle) for each character. White dots are y-axis values. B. Violin plots of mensural characters embedded with boxplots showing the range, frequency, mean (white dot), and 50 % quartile (black rectangle) for each character. Violin plots are vertically oriented mirror-imaged frequency diagrams.

Figure 7. Distribution and color pattern variation in Gekko smithii and G. hulk sp. nov. on the Thai-Malay Peninsula. A. Gekko smithii (LSUHC 15052) from Perlis State Park, Perlis, Peninsular Malaysia. B. Gekko smithii (LSUDPC 12884) from Puncak Janing, Kedah, Peninsualr Malaysia. C. Gekko smithii (LSUHC 9626) from Sedim, Kedah, Peninsular Malaysia. D. Gekko smithii (LSUDPC 12869) from Penang Hill (type locality), Penang, Peninsular Malaysia. E. Gekko smithii (LSUDPC 12886) from Lata Kedondong, Selangor, Peninsular Malaysia. F. Gekko smithii (LSUDPC 12887) from Kota Damansara, Selangor, Peninsular Malaysia. G. Gekko smithii (LSUDPC 11174) from Khaopu Khaoya, Nakhon Si Thamarat Province, Thailand. H. Gekko smithii (LSUDPC 11173) from Bacho Falls, Narathiwat Province, Thailand. I. Gekko smithii (LSUDPC 12878) from the Weang District, Narathiwat Province, Thailand. J. Gekko hulk sp. nov. (LSUDPC 12880) from the Hala-Bala Wildlife Sanctuary, Narathiwat Province, Thailand. K. Gekko hulk sp. nov. (LSUHC 8696) from Pulau Perhentian Besar, Terengganu, Peninsular Malaysia. L. Gekko hulk sp. nov. (LSUDPC 7991) from Gunung Tebu, Terengganu, Peninsular Malaysia. M. Gekko hulk sp. nov. (LSUDPC 12897) from Merapoh, Pahang, Peninsular Malaysia. N. Gekko hulk sp. nov. (LSUDPC 12897) from Pulau Tioman, Pahang, Peninsular Malaysia. Photographs by L. Lee Grismer (A, K, L, N), Evan S. H. Quah (B, C, D), Kurt H. P. Guek (E), Steven Wong (F), Henrick Bringsoe (G, H); Parinya Pawangkhanant (I), Ian Dugdale (J), and Nick Baker (M). Unannotated circles denote localities of specimens or photographs examined here or verified from other publications as well as vouchered samples in the literature.

Figure 8. Geographic variation in Gekko smithii (A-G) and G. hulk sp. nov. (H-M). A. Gekko smithii (LSUDPC 12899) from Ulu Yam, Selangor, Peninsular Malaysia. B. Gekko smithii (LSUHC 4959) from Pulau Pangkor, Perak, Peninsular Malaysia. C. Gekko smithii (LSUDPC 12898) from Ulu Yam, Selangor, Peninsular Malaysia. D. Gekko smithii (LSUDPC 12895) from Kota Damansara, Selangor, Peninsular Malaysia. E. Gekko smithii (LSUDPC 12903) from Bukit Panchor, Penang, Peninsular Malaysia. F. Gekko smithii (LSUDPC 12902) from Ulu Yam, Selangor, Peninsular Malaysia. G. Gekko smithii (THNHM 01844) from Phu Pha Phet, Satun, Province, Thailand. H. Gekko hulk sp. nov. (LSUDPC 12912) from Lata Kekabu, Setiu, Terengganu, Peninsular Malaysia. I. Gekko hulk sp. nov. (LSUDPC 8696) from Endau-Rompin, Johor, Peninsular Malaysia. J. Gekko hulk sp. nov. (LSUDPC 12953) from the Hala-Bala Wildlife Sanctuary, Narathiwat Province, Thailand. K. Gekko hulk sp. nov. (LSUHC 5152) from the Tekek-Juara Trail, Pulau Tioman, Pahang, Peninsular Malaysia. L. Gekko hulk sp. nov. (LSUHC 5873) from Kota Tinggi, Peninsular Malaysia. M. Gekko hulk sp. nov. (LSUDPC 12955) from Hutan Lipur Sekayu, Terengganu, Peninsular Malaysia. Photographs by Kurt H. P. Guek (A, C, D, F), L. Lee Grismer (B, K, L), Evan S. H. Quah (E, H), Michael Cota (G, J), M. A. Muin (I) and Syed A. Rizal (M).

Figure 11. Type series of Gekko hulk sp. nov. from Peninsular Malaysia.

Figure 12. Holotype of Gekko hulk sp. nov. (LSUHC 6284) from the Tekek-Juara Trail, Pulau Tioman, Pahang, Peninsular Malaysia. A. Top of head. B. Gular region. C. Dorsum. D. Precloacal region and ventral surfaces of the hind limbs and tail. E. Complete dorsal view. F. Complete ventral view.

Figure 13. THNHM 01841 from the Hala-Bala Wildfife Sanctuary, Narathiwat Province, Thailand. Photographs by Michael Cota.

Figure 14. Microhabitats of Gekko hulk sp. nov. on Peninsular Malaysia. A. Granite boulder microhabitat on Pulau Perhentian Besar, Terengganu. B. Forest microhabitat of the type locality along the Tekek-Juara Trail, Pulau Tioman, Pahang. Strangler Fig. microhabitat along Sungai Mentawak, Pulau Tioman, Pahang. Photographs by L. Lee Grismer.