Hemiphyllodactylus vanhoensis, Luu & Hoang & Ha & Grismer & Murdoch & Sitthivong & Phimpasone & Grismer, 2024

Luu, Vinh Quang, Hoang, Tuoi Thi, Ha, Hong Bich, Grismer, Jesse L., Murdoch, Matthew, Sitthivong, Saly, Phimpasone, Vilay & Grismer, L. Lee, 2024, Integrative taxonomy reveals two new species of karst-dwelling Hemiphyllodactylus Bleeker, 1860 (Squamata: Gekkonidae) from the border region of Laos and Vietnam, Zootaxa 5486 (1), pp. 71-108 : 102-104

Hemiphyllodactylus vanhoensis sp. nov.

Vanho Slender Gecko ( Fig. 9 ).

Holotype. Adult female VNUF R.2022.07 (Field no. TX2.22.07) collected on 11 June 2022 at 1940 hrs by Vinh Q. Luu, Nghia V. Ha, Huong V. Bui, Phuong V. Nguyen at the karst mountain of Bun Village , Tan Xuan Commune, Van Ho District, Son La Province, Vietnam (20°40'352"N 104°42'048"E; 1065 m in elevation).

Paratypes. Adult female VNUF R. 2022.09 (Field no. TX2.22.09) bears the same collection data as the holotype and juvenile male VNUF R.2023.22 (Field no. TX23.22) by Vinh Q. Luu, Le D. Phan collected on 29 August 2023 at the same locality as the holotype .

Diagnosis. Hemiphyllodactylus vanhoensis sp. nov. can be separated from all other species of Hemiphyllodactylus by possessing the unique combination of having a maximum SVL of 46.5 mm; 7 – 10 chin scales; enlarged postmentals; two or three circumnasal scales; two or three intersupranasals (=postrostrals); 10 – 12 supralabials; 10 or 11 infralabials; 15 – 19 longitudinally arranged dorsal scales at midbody contained within one eye diameter and 8 – 11 ventral scales; four to five subdigital lamellae on the first finger; four subdigital lamellae on the first toe; no pore - bearing, femoroprecloacal scales in adult females; 21 continuous, pore - bearing, femoroprecloacal scales (pitted scales in the juvenile male); no plate - like subcaudal scales; adult females not yellow; dark and light pre - and postorbital stripes in parallel extends from posterior nares to forelimb insertion; dorsolateral light - colored spots on trunk; dark dorsolateral or ventrolateral stripe on trunk; dark paravertebral markings on trunk; light - colored postsacral marking bearing anteriorly projecting arms; and caecum and gonads unpigmented. These characters are scored across all Hemiphyllodactylus species in Table 5 and from all other species of Hemiphyllodactylus from southern China, Vietnam and Laos (clades 6 in Agung et al., (2022)).

Description of holotype. Adult female SVL 44.3 mm; head triangular in dorsal profile, depressed, distinct from neck; lores flat; rostrum moderate in length (SnEye/SVL 0.09); prefrontal region weakly concave; canthus rostralis smoothly rounded, barely discernable; snout moderate, rounded in dorsal profile; eye large; ear opening elliptical, small; eye to ear distance greater than diameter of eye; rostral wider than high, bordered posteriorly by large supranasals; two intersupranasals; external nares bordered anteriorly by rostral, dorsally by supranasal, posteriorly by three postnasals, ventrally by first supralabial; 11 (R, L) rectangular supralabials tapering to below posterior margin of eye; 11 (R, L) rectangular infralabials tapering to below posterior margin of eye; scales of rostrum, lores, top of head, and occiput small, raised, those of rostrum largest; dorsal superciliaries flat, mostly square, subimbricate, largest anteriorly; mental triangular, bordered laterally by first infralabials and posteriorly by two parallelogram - shaped postmentals; each postmental in contact with first infralabial and bordered laterally by a smaller sublabial; seven chin scales; gular scales small, subimbricate, grading posteriorly into slightly larger, subimbricate throat and even larger pectoral scales which grade into slightly larger, subimbricate ventrals. Body somewhat elongate (Trunk/SVL 0.53), dorsoventrally compressed; dorsal scales small, granular, 19 dorsal scales at midbody contained within one eye diameter; ventral scales flat, subimbricate much larger than dorsal scales, eight ventral scales contained within one eye diameter; precloacal scales larger than abdominal scales; 21 continuous, pore - bearing, femoroprecloacal scales (pitted scales in the juvenile); single enlarged tubercle on lateral margin of tail base; forelimbs short, robust in stature, covered with flat, subimbricate scales dorsally and ventrally; palmar scales slightly raised, subimbricate; 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; distal lamellar formula of digits II–V (left) 4-4-4-4; four 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 raised, juxtaposed scales dorsally and by larger, flat subimbricate scales anteriorly and ventrally; plantar scales slightly raised, subimbricate; 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; distal lamellar formula of digits II–V (left) 4-5-5- 5; four 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; tail original, complete; caudal scales occurring in whorls; dorsal caudal scales larger than dorsal body scales, flat, subcycloid, subimbricate; ventrolateral caudals slightly enlarged, weakly flared anteriorly giving a fringe - like appearance; subcaudals flat, slightly larger than dorsal caudals, not plate - like. Raw morphological data are presented in Table 8 .

Variation ( Fig. 9 ). The color patterns of the paratypes generally match that of the holotype. The dark, dorsal pattern of VNUF R.2022.09 is not as bold as that of the holotype. Variation in meristic and morphometric data are presented in Table 8 .

Coloration in life ( Fig . 9). Ground color of top of head, body, and limbs dark - brown; top of head overlain with dark, cluster-shaped pattern; dark and light pre - and postorbital stripes in parallel extending from posterior nares to forelimb insertion; dark, semi - reticulate paravertebral markings extend from nape to base of tail transforming into a distinct black, post - sacral marking; lightcolored dorsolateral spots appear along the trunk; faint yellow post - sacral marking bears light - colored anteriorly projecting arms; flanks with faint, dark stripes; limbs bearing irregularly shaped diffuse dark markings and bands; gular and belly regions generally cream, except for darker lateral areas and faint stippling in scales; pigmentation density increases posteriorly; ground color of dorsal caudal region brown, bearing eight dark bands, irregular posteriorly; subcaudal region dull - yellow with scattered black and white scales.

Distribution. Hemiphyllodactylus vanhonensis sp. nov. is known only from at the Bun Village, Tan Xuan Commune, Van Ho District, Son La Province, Vietnam ( Fig. 1 ).

Natural History. Hemiphyllodactylus vanhonensis sp. nov. is an upland species and all individuals from Bun Village were found at night between 1900 hrs and 2030 hrs on leaves 4.5–5.0 m above the ground at the entrance of a karstic cave ( Fig. 10 ). The surrounding habitat was undisturbed forest. Relative temperature was 26.1–27.6 oC and humidity was 63–65%.

Etymology. The specific epithet is a toponym referring to the type locality of Van Ho District, Son La Province, Vietnam.

Comparisons. The molecular analyses indicate that Hemiphyllodactylus vanhoensis sp. nov. is the genetically distinct sister species of H. bonkowskii ( Fig. 2 ). The new species is most closely related to H. bonkowskii with a mean uncorrected pairwise sequence divergence of 3.3% between them ( Table 2 ). H. vanhoensis sp. nov. differs significantly from H. bonkowskii in mean values of SnEye (0.58 vs. 0.67, p = <0.001), SnW (0.12 vs. 0.31, p = <0.001), VS (9.67 vs. 14.33, p = <0.001), DS (17.33 vs. 25.17, p = <0.001), SL1F (4.50 vs. 5.00, p = <0.001); and SL1T (4.67 vs. 4.83, p = <0.001). Statistically significant and discrete categorical differences between H. vanhoensis sp. nov. and all other species in clade 6 are presented in Tables 5 & 6

Figures

FIGURE 1. Type localities of the species of Hemiphyllodactylus of clade 6 (Agung et al., 2022).

FIGURE 2. Maximum likelihood consensus tree of clade 6 of Hemiphyllodactylus (not including H. harterti) with Bayesian posterior probabilities (BPP) and Ultrafast Bootstrap support (UFB) values at the nodes, respectively.

FIGURE 9. Dorsal views of Hemiphyllodactylus vanhoensis sp. nov. from Bun Village, Tan Xuan Commune, Van Ho District, Son La Province, Vietnam. A: adult female holotype (VNUF R.2022.07), B: adult female paratype (VNUF R. 2022.09), and C: juvenile male paratype (VNUF R. 2023.22). Photos: Vinh Quang Luu.

FIGURE 10. Habitat of Hemiphyllodactylus vanhonensis sp. nov. is known from at the Bun Village, Tan Xuan Commune, Van Ho District, Son La Province, Vietnam. Photo: Vinh Quang Luu.