Hemiphyllodactylus ngocsonensis, Nguyen & Do & Ngo & Pham & Pham & Le & Ziegler, 2020

Nguyen, Truong Quang, Do, Quyen Hanh, Ngo, Hanh Thi, Pham, Anh Van, Pham, Cuong The, Le, Minh Duc & Ziegler, Thomas, 2020, Two new species of Hemiphyllodactylus (Squamata: Gekkonidae) from Hoa Binh Province, Vietnam, Zootaxa 4801 (3), pp. 513-536 : 523-527

Hemiphyllodactylus ngocsonensis sp. nov.

( Figs. 6 , 7 )

Holotype. IEBR 4694 (Field number HB 2014.98), adult male, collected on 19 April 2014 by C. T. Pham, H.N. Ngo, H. T. An near the entrance of a cave (20 o 27.863’N, 105 o 18.450’E, at an elevation of 652 m a.s.l.), Ngoc Son Commune , within Ngoc Son—Ngo Luong NR, Lac Son District, Hoa Binh Province, northwestern Vietnam.

Paratypes. Three adult specimens from karst forest near Ngoc Son Commune , Lac Son District, Hoa Binh Province, northwestern Vietnam : IEBR 4695 (Field number HB 2014.52), adult male, collected on 17 April 2014 by T.Q. Nguyen , C . T. Pham, H.N. Ngo on a limestone cliff (20 o 26.728’N, 105 o 20.087’E, at an elevation of 544 m a.s.l.) ; IEBR 4696 (Field number HB 2014.114), adult female, collected on 21 April 2014 by C . T. Pham, H.N. Ngo , H . T. An on a limestone boulder (20 o 25.766’N, 105 o 21.877’E, at an elevation of 415 m a.s.l.) ; IEBR 4697 (Field number HB 2014.131), adult female, collected on 03 October 2014 by C . T. Pham, H.N. Ngo on leaves near the entrance of a cave (20 o 27.812’N, 105 o 18.401’E, at an elevation of 649 m a.s.l.) .

Diagnosis. A bisexual taxon; SVL of adult 45.50–46.90 mm; dorsal scale rows 19–21; ventral scale rows 13– 15; postmentals bordering mental and first infralabial, distinctly enlarged; digital lamellae formula 3444 (forefoot) and 4554 (hindfoot); 20 pore bearing femoral and precloacal scales, in a continuous row, absent in females; cloacal spurs present in both sexes; dorsal trunk and limbs pattern brown grey; upper and lower lips with dark bars.

Description of holotype. Body dorsolaterally flattened, size small (SVL 45.50 mm), tail regenerated (TaL 31.60 mm), trunk length (TrunkL 23.60 mm), head longer than wide (HeadL 9.80 mm, HeadW 8.50 mm), eye moderate (EyeD 2.80 mm), ear opening oblique (EarD 0.91 mm), nare-eye length (NarEye 3.34 mm), snout-eye length (SnEye 4.45 mm), internarial distance (SnW 1.70 mm). Proportions: TrunkL/SVL 0.52, HeadL/SVL 0.22, HeadW/SVL 0.19, HeadW/HeadL 0.87, SnEye/HeadL 0.45, NarEye/HeadL 0.34, EyeD/HeadL 0.29, SnW/HeadL 0.17, EyeD/NarEye 0.84, SnW/HeadW 0.20.

Scalation. Rostral very large, wider than high (RW 1.60 mm, RH 0.80 mm), with a shallow, but distinct suture posteriorly; supralabials 10/11, enlarged from rostral to below eye, smaller in subocular rictus; naris in contact with rostral, first supralabial, supranasal, and two nasals posteriorly on each side; supranasals separated from each other by three small granular internasals; snout flat, covered by granular scales; pupil vertical; ear opening oblique, oval, approximately 33% of the eye diameter, without bordering enlarged scales; infralabials 10/10; mental triangular, wider than long, bordered laterally by first infralabials and posteriorly by two large postmentals; two large postmentals in contact with mental and first infralabials anteriorly; eight chin scales; gular scales small, subimbricate; throat and pectoral scales which grade into slightly larger, subimbricate. Dorsal scales small, granular, 20–21 scale rows at midbody contained within one eye diameter, enlarged tubercles absent; ventrolateral folds absent; ventral scales, flat, larger than dorsal scales, 14 scales contained within one eye diameter; enlarged, femoral and precloacal scales; 20 pore bearing femoral and precloacal scales, in continuous row; cloacal spurs one; dorsal surface of fore- and hindlimbs covered with granular scales; terminal two phalanges free, claws absent on first finger, minute on first toe, present on second to fifth digit of fore and hindfoot; pads of digits II–V each with large triangular lamellae, digital formula 3444 (forefoot) and 4554 (hindfoot); lamellae five on first fingers, five on first toes; tail regenerated; dorsal caudal scales granular; subcaudals flat, slightly larger than dorsal caudal scales.

Coloration in preservative. Ground color of dorsal surface of head and body brown grey; a small cream streak originating from posterior corner of eye on each side to the neck; neck and dorsum with some light spots; dorsal surface of limbs brown grey; upper and lower lips with dark bars; dorsal surface of tail dark grey; throat, venter, and precloacal region cream with small dark brown dots; testis white, unpigmented. For color and pattern in life see Fig. 6 .

Sexual dimorphism and variation. The females differ from male specimens in the absence of hemipenial swellings at the tail base. The scale counts vary among the type series: infralabials 9 or 10; chin scales 6–8; dorsal scale rows 19–21; ventral scale rows 13–15; precloacal pores 20 in males and absent in females; dorsal bands more distinct in one male IEBR 4695 (HB 2014.52) ( Tables 2, 3, Fig. 7 ).

Distribution. Hemiphyllodactylus ngocsonensis sp. nov. is currently known from the type locality in Ngoc Son—Ngo Luong NR, Lac Son District, Hoa Binh Province, northwestern Vietnam ( Fig. 1 ).

Etymology. Specific epithet ngocsonensis is a toponym in reference to the type locality of the species. For the common names we suggest Ngocson Slender Gecko (English) and Thạch sùng dẹp ngọc son (Vietnamese).

Natural history. Hemiphyllodactylus ngocsonensis sp. nov. inhabits disturbed evergreen karst forest of medium hardwood and shrub ( Fig. 7B ). Specimens were found at night between 19:30 and 22:00, on a limestone cliff or leaves near the entrance of a cave, ca. 0.5–1.5 m above the ground. The humidity was approximately 70–91% and the air temperature ranged from 20 to 28 oC.

Comparisons. We compare the new species from Hoa Binh Province with other members of the Hemiphyllodactylus yunnanensis species group. For comparisons with other species of Hemiphyllodactylus see Table 4. Hemiphyllodactylus ngocsonensis sp. nov. differs from H. banaensis by having fewer circumnasal scales (3 vs. 4–11 in H. banaensis ), more ventral scale rows (13–15 vs. 9–12 in H. banaensis ), and digital lamellae formula 4554 (hindfoot) (vs. 4555 in H. banaensis ); from H. changningensis Guo, Zhou, Yan & Li by having more dorsal scale rows (19–21 vs. 11–15 in H. changningensis ), more ventral scale rows (13–15 vs. 6–8 in H. changningensis ), and digital lamellae formula 3444 (forefoot) and 4554 (hindfoot) (vs. 33(4)3(4)3 and 33(4)3(4)3(4), respectively, in H. changningensis ); from H. dushanensis by having fewer chin scales (6–8 vs. 8–10 in H. dushanensis ), more dorsal scales (19–21 vs. 14–15 in H. dushanensis ), more ventral scale rows (13–15 vs. 8–9 in H. dushanensis ), fewer precloacal and femoral pores in males (20 vs. 24–26 in H. dushanensis ), digital lamellae formula 3444 (forefoot) and 4554 (hindfoot) (vs. 3454/4554 and 4555/5665, respectively, in H. dushanensis ), fewer precloacal and femoral pores (20 vs. 24–26 in H. dushanensis ), and the presence of anteriorly projecting arms on postsacral (vs. absence in H. dushanensis ); from H. hongkongensis Sung, Lee, Ng, Zhang & Yang by having more dorsal scale rows (19–21 vs. 12–15 in H. hongkongensis ), more ventral scale rows (13–15 vs. 9–10 in H. hongkongensis ), and fewer precloacal and femoral pores (20 vs. 24–25 in H. hongkongensis ); from H. huishuiensis Yan, Lin, Guo, Li & Zhou by having fewer chin scales (6–8 vs. 8–10 in H. huishuiensis ), more dorsal scale rows (19–21 vs. 13–15 in H. huishuiensis ), and more ventral scale rows (13–15 vs. 7–9 in H. huishuiensis ); from H. indosobrinus Eliades, Phimmachak, Sivongxay, Siler & Stuart by having a larger size (maximum SVL 46.90 mm vs. 39.80 mm in H. indosobrinus ), fewer supralabials (10 vs. 15 in H. indosobrinus ), fewer infralabials (9–10 vs. 12 H. indosobrinus ), fewer dorsal scale rows (19–21 vs. 30 in H. indosobrinus ), more ventral scale rows (13–15 vs. 11 in H. indosobrinus ), digital lamellae formula 3444 (forefoot) and 4554 (hindfoot) (vs. 4554 and 4555, respectively, in H. indosobrinus ), and more precloacal and femoral pores (20 vs. 18 in H. indosobrinus ); from H. jinpingensis by having a larger size (maximum SVL 46.90 mm vs. 39.60 mm in H. jinpingensis ), more dorsal scale rows (19–21 vs. 11–12 in H. jinpingensis ), more ventral scale rows (13–15 vs. 5–7 in H. jinpingensis ), fewer precloacal and femoral pores in males (19 vs. 20–24 in H. jinpingensis ), digital lamellae formula 3444 (forefoot) and 4554 (hindfoot) (vs. 3444/4444/3343 and 4444 lamellae formula, respectively, in H. jinpingensis ), and the presence of anteriorly projecting arms on postsacral (vs. absence in H. jinpingensis ); from H. kiziriani Nguyen, Botov, Le, Nophaseud, Bonkowski & Ziegler by having fewer circumnasal scales (3 vs. 4 in H. kiziriani ), more precloacal and femoral pores in males (20 vs. 10–13 in H. kiziriani ), and the absence of pitted scales in females (vs. 8–10 in H. kiziriani ); from H. longlingensis by having fewer circumnasal scales (3 vs. 4–5 in H. longlingensis ), more dorsal scale rows (19–21 vs. 10–14 in H. longlingensis ), more ventral scale rows (13–15 vs. 6–7 in H. longlingensis ), and the presence of anteriorly projecting arms on postsacral (vs. absence in H. longlingensis ); from H. serpispecus Eliades, Phimmachak, Sivongxay, Siler & Stuart by having fewer dorsal scale rows (19–21 vs. 26 in H. serpispecus ), more ventral scale rows (13–15 vs. 10 in H. serpispecus ), digital lamellae formula 4554 (hindfoot) (vs. 3445 in H. serpispecus ), and more precloacal and femoral pores in males (20 vs. 11 in H. serpispecus ); from H. typus by having fewer chin scale (6–8 vs. 9–14 in H. typus), more dorsal scale rows (19–21 vs. 12–19 in H. typus), and digital lamellae formula 4554 (hindfoot) (vs. 4454 in H. typus); from H. yunnanensis by having more dorsal scale rows (19–21 vs. 9–18 in H. yunnanensis ), more ventral scale rows (13–15 vs. 6–12 in H. yunnanensis ), digital lamellae formula 3444 (forefoot) and 4554 (hindfoot) (vs. 3333 and 3444, respectively, in H. yunnanensis ), and the presence of anteriorly projecting arms on postsacral (vs. absence in H. yunnanensis ); from H. zugi by having fewer chin scales (6–8 vs. 9–12 in H. zugi ), fewer infralabials (9–10 vs. 10–12 in H. zugi ), and digital lamellae formula 4554 (hindfoot) (vs. 4455 in H. zugi ).

Hemiphyllodactylus bonkowskii sp. nov. differs from Hemiphyllodactylus ngocsonensis sp. nov. by having more dorsal scale rows (24–27 vs. 19–21 in Hemiphyllodactylus ngocsonensis sp. nov.), fewer precloacal and femoral pores in males (19 vs. 20 in Hemiphyllodactylus ngocsonensis sp. nov.), and ratio SnW/HeadL (0.18−0.20 vs. 0.17 in Hemiphyllodactylus ngocsonensis sp. nov.).

Figures

FIGURE 1. Map of sampling sites in Hoa Binh Province, northern Vietnam: 1) Type locality of Hemiphyllodactylus bonkowskii sp. nov. in Hang Kia—Pa Co Nature Reserve; 2) Type locality of Hemiphyllodactylus ngocsonensis sp. nov. in Ngoc Son—Ngo Luong Nature Reserve.

FIGURE 6. The male holotype of Hemiphyllodactylus ngocsonensis sp. nov. (IEBR 4694): A) Dorsal view in life, B) Precloacal region with precloacal and femoral pores in a continuous series, C) Subdigital view of right hand, and D) Subdigital view of right foot. Photos: C.T. Pham, Q.H. Do. Scale bar = 1 mm.

FIGURE 7. Hemiphyllodactylus ngocsonensis sp. nov. in life: A) The male paratype (IEBR 4695) and B) The female paratype (IEBR 4696). Photos: C.T. Pham.