Hemiphyllodactylus hongkongensis, Sung & Lee & Ng & Zhang & Yang, 2018

Sung, Yik-Hei, Lee, Wing-Ho, Ng, Ho-Nam, Zhang, Yanjie & Yang, Jian-Huan, 2018, A new species of Hemiphyllodactylus (Squamata: Gekkonidae) from Hong Kong, Zootaxa 4392 (2), pp. 361-373 : 365-369

Hemiphyllodactylus hongkongensis sp. nov.

Hong Kong Slender Gecko Fig. 2 , 3

Holotype. SYS r001735 ( Museum of Biology , Sun Yat-sen University ), adult male collected by Wing-Ho Lee and Ho-Nam Ng on 20 April 2017 in Aberdeen Country Park, Hong Kong (22°15.51' N, 114°9.69' E; 120 m a.s.l.; Fig. 4 )

Paratypes. SYS r001728, SYS r001729 and SYS r001730, three adult female specimens were collected by Yik-Hei Sung, Wing-Ho Lee and Ho-Nam Ng on 7 June 2016 and 14 October 2016 in Aberdeen Country Park, Hong Kong (22°15.51' N, 114°9.69' E; 120 m a.s.l.). SYS r001732, SYS r001733 and SYS r001734, two adult females and one adult male, were collected by Yik-Hei Sung, Wing-Ho Lee and Ho-Nam Ng on 20 April 2017 in Aberdeen Country Park, Hong Kong (22°15.51' N, 114°9.69' E; 120 m a.s.l.). SYS r001731, one adult female, was collected by Yik-Hei Sung, Wing-Ho Lee and Ho-Nam Ng on 8 April 2017 on Po Toi Island, Hong Kong (22°9.83' N, 114°15.33' E; 50 m a.s.l.).

Diagnosis. Hemiphyllodactylus hongkongensis sp. nov. can be separated from all other species of Hemiphyllodactylus by having the unique combination of 5 – 6 chin scales; a manual lamellar formula of 3‒3(4)‒4‒ 4; a pedal lamellar formula of 3(4) – 4(5) – 4(5) – 4; 24 – 25 continuous femoral and precloacal pores; 12 – 15 dorsal scales contained in diameter of eye; and 9 – 10 ventral scales contained in diameter of eye.

Description of Holotype: Adult male; head triangular in dorsal profile, depressed, distinct from neck; lores and interorbital regions flat; rostrum relatively long (NarEye/ HeadL = 0.26); prefrontal region flat to weakly concave; canthus rostralis smoothly rounded, snout moderate, rounded in dorsal profile; eye large; ear opening oval, small; eye to ear distance greater than diameter of eye; rostral wider than high, bordered posteriorly by large supranasals; three internasals (=postnasals); external nares bordered anteriorly by rostral, dorsally by supranasal, posteriorly by one postnasals, ventrally by first supralabial (=circumnasals 3R,L); 10/10 (right/left, hereafter) square supralabials tapering to below posterior margin of orbit; 9/10 square infralabials tapering to below posterior margin of orbit; dorsal superciliaries flat, rectangular, imbricate; mental triangular, bordered laterally by first infralabials and posteriorly by two large postmentals; each postmental bordered laterally by a single sublabial; row of smaller scales extending transversely from juncture of second and third infralabials and contacting mental; gular scales triangular small, granular, grading posteriorly into slightly larger, subimbricate, throat and pectoral scales which grade into slightly larger, subimbricate ventrals.

Body somewhat elongate, dorsoventrally compressed; ventrolateral folds absent; dorsal scales small, granular, 15 scales contained within one eye diameter; ventral scales, flat, subimbricate, larger than dorsal scales, 10 scales contained within one eye diameter; no enlarged, precloacal scales; 24 pore-bearing scales extending from midway between the knee and hind limb insertion of one leg to the other; forelimbs short, robust in stature, covered with granular scales dorsally and with slightly larger, flat, subimbricate scales ventrally; palmar scales flat, imbricate; all digits except digit I well developed; digit I vestigial, clawless; distal, subdigital lamellae of digits II‒V undivided, angular and U-shaped; lamellae proximal to these transversely expanded; lamellar formula of digits II‒V 3‒4 ‒4‒4 on both hands; five transversely expanded lamellae on digit I; claws on digits II‒V well developed, unsheathed; distal portions of digits strongly curved, terminal joint free, arising from central portion of lamellar pad; hind limbs short, more robust than forelimbs, covered with slightly pointed, juxtaposed scales dorsally and by larger, flat subimbricate scales ventrally; all digits except digit I well developed; digit I vestigial, clawless; distal, subdigital lamellae of digits II‒V undivided, angular and U-shaped; lamellae proximal to these transversely expanded; lamellar formula of digits II‒V 4‒5 ‒5‒4 on both feet; five transversely expanded lamellae on digit I; claws on digits II‒V well developed, unsheathed; distal portions of digits strongly curved, terminal joint free, arising from central portion of lamellar pad; posterior section of tail broken, round in cross-section; all caudal scales flat, subimbricate, not forming distinct caudal segments. Morphometric data are presented in Table 3.

Color in preservative ( Fig. 3 ). Dorsal surface of head, body, and limbs dull brown, with diffused dark and cream mottling; dorsal surface of tail light grey, faint diffuse light and dark bands; ventral surface of the head, limbs and body cream, dark mottling on throat, limbs and tail; caecum unpigmented.

Variation. The coloration of most specimens is similar to the holotype, having dark transverse blotches on the dorsal surface of body and distinctive postsacral mark ( Fig. 2 ). However, one female paratype (SYS r001732) has a more uniform color on the dorsal surface, without dark dorsal transverse blotches and postsacral mark ( Fig. 5 ).

Comparisons. We compared Hemiphyllodactylus hongkongensis with other members of the genus Hemiphyllodactylus from China and Indochina based on data obtained from the literature. We show the diagnostic characters separating this species from other nominal taxa of Hemiphyllodactylus in Table 4.

Hemiphyllodactylus hongkongensis sp. nov. has 5 – 6 chin scales, which separates it from H. changningensis Guo, Zhou, Yan & Li (7 – 8), H. chiangmaiensis Grismer, Wood & Cota (8‒12), H. dushanensis (8 – 10), H.

huishuiensis (8 – 10), H. jinpingensis Zhou & Liu (7 – 9), H. longlingensis Zhou & Liu (7 – 9), H. typus Bleeker (9 – 14), H. yunnanensis (7 – 8), and H. zugi (9 – 12). Hemiphyllodactylus hongkongensis sp. nov. has a manual lamellar formula of 3 – 4 – 4 – 4 or 3 – 3 – 4 – 4 which distinguish it from H. changningensis (3 – 3(4) – 3(4) – 3), H. chiangmaiensis (3 – 3 – 3 – 3, 3 – 4 – 3 – 3), and H. dushanensis (3 – 4 – 5 – 4, 4 – 5 – 5 – 4). It differs from H. banaensis Ngo, Grismer, Thai & Wood (4 – 5 – 5 – 5), H. dushanensis (4 – 5 – 5 – 5, 5 – 6 – 6 – 5), and H. zugi (4 – 5 – 5 – 5) by having a pedal lamellar formula of 3 – 4 – 4 – 4, 4 – 4 – 4 – 4 or 4 – 5 – 5 – 4. It differs from H. banaensis (18 – 21), H. changningensis (19 – 22), H. kiziriani Nguyen, Botov, Le, Nophaseud, Zug, Bonkowski & Ziegler (10 – 13), H. huishuiensis (0 – 20), H. yunnanensis (0 – 20), and H. zugi (18 – 21) by having 24 – 25 continuous femoral and precloacal pores in adult males. Hemiphyllodactylus hongkongensis sp. nov. has 12 – 15 dorsal scales contained in the diameter of the eye, which separates it from H. banaensis (17 – 20), and H. zugi (20 – 22). It differs from H. changningensis (6 – 8), H. jinpingensis (5 – 7), H. kiziriani (11 – 15), H. longlingensis (6 – 7), H. yunnanensis (5 – 7) and H. zugi (15 – 16) by having 9 – 10 ventral scales contained in the diameter of the eye.

Etymology. The specific epithet “ hongkongensis ’ is in reference to the type locality, Hong Kong SAR, China. As an English common name, we suggest “ Hong Kong Slender Gecko”.

Distribution. In Hong Kong, records of Hemiphyllodactylus have been made on Hong Kong Island (including Aberdeen Country Park and Pokfulam Country Park), Shek Kwu Chau, and Po Toi Island ( Karsen et al. 1998) ( Fig. 4 ).

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Figures

FIGURE 2. Adult male holotype (SYS r001735) of Hemiphyllodactylus hongkongensis sp. nov. in life from Aberdeen Country Park, Hong Kong SAR, China.

FIGURE 3. Male holotype (SYS r001735) of Hemiphyllodactylus hongkongensis sp. nov. collected from Aberdeen Country Park, Hong Kong SAR, China.

FIGURE 4. Map showing the collection localities of Hemiphyllodactylus hongkongensis sp. nov. from Aberdeen Country Park and Po Toi Island (black dots), Hong Kong SAR, China. Black crosses, including Shek Kwu Chau and Pokfulam Country Park, indicates the localities where Hemiphyllodactylus individuals were recorded but could not be collected nor examined in this study.

FIGURE 5. Female paratype (SYS r001732) of Hemiphyllodactylus hongkongensis sp. nov. having uniform color on the dorsal surface.