Hemiphyllodactylus xiengkhouangensis, Luu & Sitthivong & Hoang & Ha & Ha & Xayasith & Ziegler & Grismer, 2025

Luu, Vinh Quang, Sitthivong, Saly, Hoang, Tuoi Thi, Ha, Hong Bich, Ha, Huan Van, Xayasith, Santi, Ziegler, Thomas & Grismer, L. Lee, 2025, Two more new species of Hemiphyllodactylus Bleeker, 1860 (Squamata: Gekkonidae) from Laos and Vietnam identified using an integrative taxonomic approach, Zootaxa 5686 (2), pp. 211-238 : 225-231

publication ID	https://doi.org/10.11646/zootaxa.5686.2.3
publication LSID	lsid:zoobank.org:pub:7B6ABF33-AEF7-46B5-9CF2-00AC61F13F0D
persistent identifier	https://treatment.plazi.org/id/03B887D4-AC47-167F-FC92-F909FD76FDC7
treatment provided by	Plazi
scientific name	Hemiphyllodactylus xiengkhouangensis
status	sp. nov.

Treatment

Hemiphyllodactylus xiengkhouangensis sp. nov.

Xiengkhouang Slender Gecko ( Figs. 5 View FIGURE 5 , 6 View FIGURE 6 ).

Holotype. Adult male VNUF R.2025.02 (Field no. KNGAN. XK.02) collected on 19 May 2023 at 19:45 hrs by Saly Sitthivong at the Phouvieng Village , Khuon District, Xiengkhouang Province, Laos (19°14'39"N 103°35'47"E; 1180 m in elevation). GoogleMaps

Paratypes. Adult female VNUF R.2025.03 (Field no. KNGAN.XK.03 and adult male NUOL R.2025.01 (Field no. KNGAN. XK.01) bear the same collection data as the holotype. GoogleMaps

Diagnosis. Hemiphyllodactylus xiengkhouangensis sp. nov. can be separated from all other species of Hemiphyllodactylus by possessing the unique combination of having a maximum SVL of 41.7 mm; chin scales 8–10; postmentals enlarged; circumnasal scales three or four; intersupranasals (=postrostrals) two or three; supralabials 9–12; infralabials 8–11; dorsal scales 16–20; ventral scales 9–11; subdigital lamellae on the first finger four or five; femoral and precloacal pores 20 or 21, in a continuous row in males and 12 pitted scales in the female; no plate - like subcaudal scales; dorsal surfaces of head, body, and limbs light-brown, heavily mottled with darker markings; top of head overlain with a faint, irregular dark pattern; dark stripe extends from the external nares through the eye to the region just posterior of forelimb insertion on the body; ventral surfaces of the trunk and limbs uniformly pale-yellow with darker lateral areas; ventral surface of original tail orange with ventrolaterally dark pigmentation. Three selective color pattern characters (DorBodPatrn, VenBodPatrn, and VenTalPatrn as mentioned above) are scored across closely related Hemiphyllodactylus species in Tables 3 and 4.

Description of holotype. Adult male, SVL 41.7 mm; triangularly shaped head in dorsal profile, depressed, distinct from neck; lores flat; rostrum moderate in length (SnEye/SVL 0.11); prefrontal region slightly concave; canthal ridge gently rounded, indistinct; snout moderate, dorsally rounded; eye large; ear opening elliptical, small; eye to ear distance greater than diameter of eye; rostral rectangular, wider than high, shortly divided dorsally by straight rostral groove, bordered by enlarge supra - nasals posteriorly; two intersupranasals (=postnasals); external nares bordered anteriorly by rostral, dorsally by supranasal, posteriorly by two postnasals, ventrally by first supralabial; rectangular supralabials 11/12 (R, L); rectangular infralabials 11 (R, L); scales on rostrum, lores, top of head, and occiput small, granular with rostrum scales largest and slightly raised; superciliaries dorsally flat, mostly square, subimbricate, largest anteriorly; mental triangular, bordered laterally by first infralabials, posteriorly by two enlarged postmentals; each postmental in contact with first infralabial; chin scales nine; gular scales small, subimbricate, grading posteriorly into weakly larger, subimbricate throat.

Body elongate (Trunk/SVL 0.50), dorsoventrally compressed; dorsal scales small, granular, 20 at midbody contained within one eye diameter; ventral scales flat, subimbricate much larger than dorsal scales, 11 at midbody ventral within the length of eye diameter; precloacal scales slightly larger than abdominal scales; continuous femoral and precloacal pore-bearing scales 20; enlarged tubercle on anterior margin of hemipenial swelling single; forelimbs short and robust, dorsally and ventrally covered with flat, subimbricate scales; palmar scales flat, subimbricate; all digits except digit I well - developed; digit I vestigial, clawless bearing five subdigital lamellae; 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 4 - 4 - 4 - 4 (left); claws on digits II–V well-developed, unsheathed; distal portions of digits strongly curved, terminal joint free, arising from central portion of lamellar pad; hindlimbs short, more robust than forelimbs, covered with flat, juxtaposed scales dorsally and larger, flat subimbricate scales ventrally; plantar scales low, flat, subimbricate; all digits except digit I well - developed; digit I vestigial, clawless bearing five subdigital lamellae; 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 4 - 5 - 5 - 5 (left); claws on digits II–V welldeveloped, unsheathed; distal portions of digits strongly curved, terminal joint free, arising from central portion of lamellar pad; tail partially regenerated, 36 mm in length; caudal scales non-whorled; dorsal caudal scales of original tail larger than dorsal body scales, flat, subcycloid, subimbricate; subcaudals weakly larger than dorsal caudals, not plate - like. Morphological characters are presented in Table 9.

Coloration in life. Dorsal surfaces of head, body, and limbs light-brown, heavily mottled with darker markings; top of head overlain with a faint, irregular dark pattern; dark stripe extends from the external nares through the eye to the region just posterior of forelimb insertion on the body; eye large with a vertical pupil and coppery brown iris speckled with fine black reticulations; paravertebral region with poorly defined dark blotches continuing from nape to tail base transforming into a distinct, black, post - sacral band; cream post - sacral marking immediately posterior to black post - sacral band; bearing light-colored, anteriorly projecting arms; dorsolateral region of trunk with diffuse dark speckling and scattered light spots on the lateral side; upper body with numerous brown spots irregularly distributed; limbs bearing irregularly shaped, dark markings, especially on the hindlimbs; original portion of tail with alternating unclearly dark and light-brown bands; regenerated portion tail grey with scattered dark flecks; gular region pale-yellow to cream; ventral surface of the trunk uniformly pale-yellow with darker lateral areas; ventral surface of limbs; ventral surface of original tail distinctly orange with laterally dark pigmentation; subcaudal of regenerated tail portion grey with dark markings.

Variation ( Figs 5 View FIGURE 5 , 6 View FIGURE 6 ). The dorsal pattern on the head, body, limbs, and tail of the female paratype ( VNUF R.2025.03) is faded or nearly absent, whereas the male paratype ( NUOL R.2025.01) is darker brown with a more faded pattern compared to the holotype. The ventral surface of the tail of the paratype is uniformly orange, lacking dark lateral spots. Variation in scale counts and morphomeric data are presented in Table 9 .

Hemiphyllodactylus xiengkhouangensis sp. nov. Hemiphyllodactylus yenchauensis VNUF R.2025.02 NOUL R.2025.01 VNUF R.2025.03 VNUF R.2025.05 VNUF R.2025.06 Holotype Paratype Paratype Holotype Paratype SL1F 5/5 4/4 5/5 5/5 4/5 SL1T 5/5 5/5 5/5 5/5 5/6 Total femoroprecloacal pores 20 (continuous) 21(continuous) 12 (dim) 0 0 CloacS on each side 2 1 2 1 1 Subcaudals enlarged, plate - like 0 0 0 0 0

sp. nov.

Distribution. Hemiphyllodactylus xiengkhouangensis sp. nov. is only known from the type locality at Phouvieng Village, Khuon District, Xiengkhouang Province, Laos ( Fig. 1 View FIGURE 1 ).

Natural History. Hemiphyllodactylus xiengkhouangensis sp. nov. is an upland species, and all individuals were collected from Phouvieng Village at night from 19:00–20:30 hrs, on garden vegetation and houses, at heights of 0.5–1.5 meters above the ground ( Fig. 7 View FIGURE 7 ). The female paratype ( VNUF R.2025.03) has two eggs .

Etymology. The specific name is derived from the type locality of Xiengkhouang Province, Laos.

Comparisons. Hemiphyllodactylus xiengkhouangensis sp. nov. is the sister species to H. banaensis with uncorrected pairwise sequence divergence of 11.4% ( Table 2). H. xiengkhouangensis sp. nov. differs significantly from H. banaensis in mean values of SVL (1.59 vs. 1.69, p = 0.028), Trunk (1.3 vs. 1.36, p <0.001) and HeadW (0.84 vs. 0.87, p = 0.004), and the presence of a cream-colored venter (vs. dark brown in H. banaensis ), and the presence of orange coloration in the subcaudal region of the original tail (vs. dark brown H. banaensis ). Morphologically, H. xiengkhouangensis sp. nov. (n = 3) is very similar to H. serpispecus (n = 1) in terms of morphometric data. However, the new species can be distinguished from H. serpispecus by the significantly lower mean number of dorsal scales (DS: 18.33 vs. 26; p <0.001), the presence of a dark grey dorsum with irregular zig-zag markings (vs. a chevron pattern in H. serpispecus ), and an orange venter of the original tail (vs. cream-colored in H. serpispecus ). Raw morphometric, meristic, and categorical data used in the statistical analyses are presented in Tables 3 and 4. Statistically significant differences between Hemiphyllodactylus xiengkhouangensis sp. nov. and other closely related species are provided in Tables 5 and 7.