Hemiphyllodactylus typus Bleeker, 1860

Hemiphyllodactylus typus Bleeker, 1860 View in CoL

Figures 8–10 View FIGURE 8 View FIGURE 9 View FIGURE 10 , Table 6.

Holotype. BMNH 1946.8 .30.83, an adult female, collected from Agam , Sumatra, Indonesia.

Specimens examined. A juvenile and six adult female specimens. Female SYS r002677 collected from Linchunling Park (18.2636°N, 109.5209°E; 100 m a.s.l.), Sanya City , Hainan Province, China on 20 July 2022 by Hao-Tian Wang , Shuo Qi , Yong-Heng Zhu and Pi-Peng Li ; female SYS r002678–2679 collected from the same locality on 19 July 2022 by Zhao-Xuan Jiang ; juvenile SYS r002810 collected from Mt. Aopenling (18.8097°N, 110.1989°E; 100 m a.s.l.), Wanning City , Hainan Province, China on April 2021 by Ming-Hong Huang , and only used in molecular analyses; female SYS r002860–2861 collected from Mt. Diaoluo (18.7014°N, 109.8367°E; 530 m a.s.l.), Lingshui Li Autonomous County, Hainan Province, China on 19 April 2024 by Hao-Yu Zhang ; female CIB DLS20220701005 collected from Mt. Diaoluo (18.6959°N, 109.8811°E; 670 m a.s.l.), Lingshui Li Autonomous County , Hainan Province, China on 01 July 2022 by Pu-Yang Zheng GoogleMaps .

Etymology. Bleeker (1860) offered no explanation of his selection of the name typus . Zug (2010) assumed that

Bleeker chose typus because this species represented the type species for his new genus Hemiphyllodactylus . Common names. Indo-pacific Slender Gecko in English; 半叶DẼ (bàn yѐ zhǐ hǔ) in Chinese.

Diagnosis. All-female taxon; pigmented caecum and gonadal ducts; if present (uncommonly), femoral pore series separate from precloacal pore series; chin scales bordering mental and first infralabial not greatly enlarged; lamellae formulae of digits II–V 3-4-4-4 (hands) and 4-4-5-4 (feet); average adult SVL ~ 38 mm; series of white spots dorsolaterally on trunk and bright postsacral bar of white and dark brown ( Zug 2010).

Description of the six adult specimens from Hainan. All females, SVL 29.6–37.8 mm; head triangular in dorsal view, moderate size (HL/SVL 0.20–0.25), length longer than width (HW/HL 0.60–0.82), depressed, distinct from neck; snout rounded anteriorly, moderate in length (SN/HL 0.39–0.49); lores concave; prefrontal region weakly convex; rostral regular rectangular, wider than mental, bordered posteriorly by first large supranasals; external nares oval, surrounded by rostral, first supralabial, supranasal and one or two postnasals posteriorly (four or five circumnasals collectively); two or three intersupranasals; eye large (ED/HL 0.19–0.24), pupil vertical, margins crenulated; ear opening elliptical, obliquely orientated; 10–12 square supralabials tapering to below posterior margin of orbit; 9–11 square infralabials tapering to below posterior margin of orbit; scales of rostrum and lores, raised; scales on top of head and occiput small, granular; superciliaries raised, rectangular; mental triangular, bordered laterally by first infralabials and posteriorly by two slightly enlarged postmentals; 9–12 chin scales contacting the medial edge of the infralabials and mental from the juncture of the second and third infralabials on both sides; gular scales triangular, small, granular.

Body slender, elongate (AG/SVL 0.51–0.61), dorsoventrally compressed; dorsals smooth, round or oval, granular and juxtaposed, 13–15 scales contained within one eye diameter; ventrals distinctly larger than dorsal scales, flat, imbricate and largest in middle of belly, 8–10 scales contained within one eye diameter; precloacal scales non-enlarged; most specimens with no pore-bearing femoral or precloacal scales, only SYS r002861 has 12 continuous pore-bearing femoral and precloacal scales.

Fore- and hind-limbs short, dorsal surface covered with smooth, granular scales and slightly larger, flat, subimbricate scales on ventral surface; all digits except digit I well-developed, clawed and robustly dilated distally; digit I vestigial, clawless with transversely expanded lamellae, four or five on first fingers and five or six on first toes; claws on digits II–V well developed, unsheathed; subdigital lamellae of digits II–V divided, angular and Ushaped; lamellae proximal to these transversely expanded, undivided; distal subdigital lamellar formula 3-4-4-4 (fingers II–V) and 4-5-5-4 (toes II–V); relative length fingers and toes I<II<III≈V<IV.

Tail slightly swollen at base, oval in section; caudal scales not in whorls; dorsal caudal scales larger than dorsal body scales, flat, subcycloid, subimbricate; subcaudals slightly larger than dorsal caudals, not plate-like; one or two cloacal spurs on each side.

Other raw mensural data and ratios are shown in Table 6.

Coloration in life. The following description was made when the specimens were photographed the morning after capture, approximately 12 hours after the time of collection. Ground color of top of head, body, and limbs dusky tan to reddish brown; a distinct dark-colored loreal and postorbital stripe extending to at least base of neck; a trident-like marking on the occipital region; pupil black; iris yellowish brown with dark brown irresular thin veins; series of brightly pink to orange spots on the trunk, dorsal head and limbs, often darkly edged; series of dark spots interspersed with these on the trunk; light brownish postsacral marking variably bearing anteriorly projecting arms; ventral surface of head, body and limbs pale white; and caecum and gonads pigmented; the coloration of tail dorsum distinct from the body, yellowish beige in general with some lighter brown bands not encircling tail; median subcaudal region bright orange.

Coloration in alcohol. In preservative, dorsal ground color of head, body, and limbs become darker; ventral surface grayish white; all light-colored spots and bands on the top of head, body, limbs and subcaudal faded to grayish white; dark spots on dorsal surface blurred.

Variation. Measurements and scale counts of seven individuals are shown in Table 6. The newly collected adult specimens generally resemble other populations in appearance but display some distinct morphological differences, i.e. a series of bright pink or orange spots along the trunk, head dorsum, and limbs (versus white spots).

Distribution and ecology. Currently Hemiphyllodactylus typus is known throughout the Pacific from Hawaii and French Polynesia westward into coastal Indo-Australia and southward to the Mascarene Islands ( Zug 2010, 2013; Uetz et al. 2024). In China, this species is only known on Hainan Island (Sanya, Lingshui, Wenchang and Wanning; Zhou et al. 2024b; this study) and eastern Taiwan Island (including Orchid Island and Green Island; Lee et al. 2019).

In Sanya City, three individuals were caught between 21:00–01:00 from the fences on either side of the steps and from the leaves of nearby trees in the park. These habitats were also inhabited by two other gekkonid species, Hemidactylus frenatus and Gehyra mutilata . In Wanning City, the specimen was captured on an areca tree approximately 5m above the ground on the morning. The specimens collected from Mt. Diaoluo were all found at night, on the backs of road and viewing platform railings

Two opal eggs were visible through the skin of the belly (SYS r002679). This indicates that July falls within the reproductive season of this species.

Remarks. Two specimens of Hemiphyllodactylus typus (MVZ 42817–42818), collected from Hainan Island in March 1946 by S. F. Cook Jr, are housed at the Museum of Vertebrate Zoology, University of California, Berkeley, USA. Unfortunately, the label lacks specific locality information ( Figure 11 View FIGURE 11 ). We also have viewed several online photos (iNaturalist, https://www.inaturalist.org/) taken from Mt. Jianfengling and Mt. Qixianling, and the dorsal patterns indicate that these individuals might belong to H. typus . However, for the sake of greater accuracy, it remains uncertain whether this species occurs in these localities of Hainan until additional vouchers are obtained.