Amolops truongi, Pham & Pham & Ngo & Nenh & Ziegler & Le, 2023

Pham, Anh Van, Pham, Cuong The, Ngo, Hanh Thi, Nenh, Sung Ba, Ziegler, Thomas & Le, Minh Duc, 2023, A new species of Amolops (Anura: Ranidae) from Son La Province, northwestern Vietnam, Raffles Bulletin of Zoology 71, pp. 51-69 : 56-64

Amolops truongi , new species

( Figs. 3–6 )

Holotype. ZVNU.2022.01 (Field No.SL 2016.344), adult male, collected by N. B. Song and T. V. Dau on 29 October 2016 in the forest near Phieng Ai Village (21°34.956′N, 104°17.160′E, at an elevation of 1,360 m a.s.l.), Ngoc Chien Commune, Muong La District, Son La Province, Vietnam.

Paratypes. ZVNU.2022.02 (Field No.SL 2016.342), IEBR A.4993 (Field No.SL 2016.346), ZVNU.2022.03 (Field No.SL 2016.347), IEBR A.4994 (Field No.SL 2016.348), IEBR A.4995 (Field No.SL 2016.349), ZVNU.2022.04 (Field No.SL 2016.352), adult males ; ZVNU.2022.05 (Field No.SL 2016.339), ZVNU.2022.06 (Field No.SL 2016.340) & IEBR A.4996 (Field No.SL 2016.343), adult females (the same data as the holotype) .

Diagnosis. The new species from Son La Province is assigned to the Amolops monticola group on the basis of the following morphological characters: dorsal skin smooth, lateral side of head dark, with a light-coloured upper lip-stripe extending to the shoulder, and dorsolateral folds distinct ( Stuart et al., 2010; Jiang et al., 2016). The new species is also supported as a member of the A. monticola group based on the molecular data ( Fig. 2 ). Amolops truongi , new species, is distinguishable from its congeners by a combination of the following morphological characters: (1) SVL 37.5–41.3 mm in males, 61.5–62.5 mm in females; (2) head longer than wide; (3) vomerine teeth present; (4) snout long (SE/SVL 0.16 in males, 0.15 in females); (5) tympanum distinct, round (TD/ED 0.37–0.39 in males, 0.36–0.37 in females); (6) skin smooth; (7) supratympanic fold indistinct; (8) dorsolateral fold present; (9) webbing formula I0–1/2II0–1III0–1IV1–0V; (10) in life, dorsum lightly grey with indistinct greenish dots or greenish spots; (11) head and body with irregular dorsolateral brown stripe; (12) dorsal surface of forelimbs and hindlimbs light grey with brown crossbars, darker on hindlimbs; (13) throat, chest and belly white; vocal sac yellowish; (14) external vocal sac present and finger I with nuptial pad in males.

Description of holotype. Adult male; SVL 41.3 mm; body long (AG/SVL 0.45); head large, broad and flat (HL/SVL 0.33, HW/SVL 0.31, HD/SVL 0.15), longer than wide (HL 14.6 mm, HW 13.0 mm); snout point anteriorly in dorsal view (SE/SVL 0.16), projecting beyond lower jaw; nostril lateral, closer to snout tip than to eye (SND 3.0 mm, END 3.6 mm); canthus rostralis distinct; loreal region concave; snout length greater than eye diameter (SE 6.6 mm, ED 5.9 mm); eyes very large (ED/HL 0.40, ED/SE 0.89 mm); pupil horizontally oval; internarial distance wider than interorbital distance and upper eyelid (IND 4.5 mm, IOD 3.5 mm, UEW 4.0 mm); tympanum distinct, round (TD/ED 0.36); vomerine teeth present, on two short oblique, cresentic ridges between choanae; tongue cordiform, notched posteriorly; vocal sac opening on floor of mouth at corner, sac-like gular pouch, front margin positioned near to level of centre of orbit.

Forelimbs long (FLL/SVL 0.69); forearm very robust; relative finger lengths: I<II<IV<III; fingers without webbing; tips of fingers expanded into discs, second to fourth with circummarginal grooves; tip of first finger smaller, without circummarginal groove; width of disc of finger III smaller than the diameter of tympanum (TD 2.2 mm, FTD 1.5 mm); subarticular tubercles oval, formula 1, 1, 2, 2; metatarsal tubercle indistinct; glandular nuptial pad on finger I, covering medial surface to base of finger disc.

Hindlimbs very long (HLL/SVL 1.86); tibia longer than thigh (FL 21.1 mm, TL 24.8 mm); relative toe length I<II<III<V<IV; tips of toes expanded into discs; width of disc of toe IV smaller than that of finger III; webbing formula I0–1/2II0–1III0–1IV1–0V; subarticular tubercles oval, formula 1, 1, 2, 3, 2; inner metatarsal tubercle elongate; outer metatarsal tubercle absent.

Skin texture in life. Dorsal and lateral of head and body smooth, except few very small tubercles present on temporal head, above tibias and vent; supratympanic fold indistinct; dorsolateral fold distinct, from rear of upper eyelid to near vent; ventral surfaces smooth except lightly flat tubercles on basal ventral surface of thigh.

Colouration in life. Dorsum light grey with scattered small, indistinct greenish dots; head and body with irregular dorsolateral brown stripes; lateral side of head and tympanum brown; flanks light grey; a white stripe extending from the tip of the snout to the anterior joint of the shoulder on each side; gold around iris; dorsal surface of forelimbs and hindlimbs light grey with brown crossbars, darker on hindlimbs; throat, chest and belly white; vocal sac yellowish; ventral surface of forelimbs and hindlimbs slightly cream; toe webbing brown.

Colouration in preservative. Dorsal surface of the head and body dark grey; upper margins of the dorsolateral fold, side of head and tympanum dark brown; side of flanks yellowish; dorsal surface of forelimbs and hindlimbs lightly brown with dark crossbars; throat, chest and belly white with some brownish dots.

Sexual dimorphism and variation. Males have distinct vocal sacs (absent in females), distinct nuptial pads on finger I (absent in females), and thick, robust forearms (forearms thin and slender in females). In terms of colouration pattern, dorsal surface of head and body is light grey with some greenish spots in one adult male ZVNU.2022.04 and one adult female IEBR A.A.4996. Measurements and morphological characters of the type series are given in Table 2 .

Etymology. The species was named after the eminent zoologist from the Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, Prof. Dr. Truong Quang Nguyen, who has made tremendous contributions to the study of Vietnam’s herpetofauna.

Distribution. Amolops truongi , new species, is currently known only from the type locality in Muong La District, Son La Province, Vietnam ( Fig. 1 ).

Ecological notes. Specimens were found at night between 1830 and 2100 hours, on trees or limestone cliffs nearby a stream, about 0.3–1.0 m above the ground, at elevations between 1,200 and 1,400 m a.s.l. The surrounding habitat was secondary forest of medium with shrubs. Air temperature was 20–25°C and relative humidity was 75–85%. Other amphibian species found at the site were Odorrana chapaensis ( Bourret, 1937) , O. jingdongensis Fei, Ye & Li, 2001 , O. nasica ( Boulenger, 1903) , Kurixalus bisacculus ( Taylor, 1962) , and Polypedates mutus ( Smith, 1940) .

Comparisons. Morphological character analyses clearly indicate that the new species belongs to the A. monticola group. We compared the new species with other members of the A. monticola group and data obtained from the literature ( Boulenger, 1920; Pope, 1929; Ray, 1992; Wu & Tian, 1995; Inger & Chanard, 1997; Liu et al., 2000; Bain et al., 2003, 2006; Bain & Nguyen, 2004; Zhao et al., 2005; Fei et al., 2009, 2010; Biju et al., 2010; Stuart et al., 2010; Jiang et al., 2016; Yuan et al., 2018; Yu et al., 2019; Che et al., 2020; Gan et al., 2020a, b; Patel et al., 2021) ( Table 3).

Amolops truongi , new species, differs from from A. compotrix ( Bain, Stuart & Orlov, 2006) by having a larger size (SVL mean ± SD 39.5 ± 1.5 mm [n = 7] vs. 36.8 ± 3.1 mm [n = 10] in males; 62.1 ± 0.55 mm [n = 3] vs. 56.4 ± 0.7 mm [n = 3] in females), a lower ratio of TD/ED (0.37 vs. 0.41–0.51 in males; 0.36–0.37 vs. 0.41–0.45 in females; Tables 2, 4), the absence of circummarginal grooves on disc of grooves on disc of first finger and outer metatarsal tubercle on the hindlimbs (vs. present), and different dorsal colour pattern (light grey with scattered small, indistinct greenish dots vs. bluish green) ( Fig. 7A ); from A. cucae ( Bain, Stuart & Orlov, 2006) by having a smaller size in females (SVL 61.5–62.5 mm vs. 65.8–68.0 mm), the absence of circummarginal grooves on disc of grooves on disc of first finger and outer metatarsal tubercle on the hindlimbs (vs. presence), and different dorsal colour pattern (light grey with scattered small, indistinct greenish dots vs. light green) ( Fig. 7B ); from A. adicola Patel, Garg, Das, Stuart & Biju, 2021 by having a smaller size in males (SVL 37.5–41.3 mm vs. 44.0–47.0 mm), the absence of circummarginal grooves on disc of first finger (vs. presence), and different dorsal colour pattern (light grey with scattered small, indistinct greenish dots vs. reddish brown); from A. akhaorum Stuart, Bain, Phimmachak & Spence, 2010 by having a larger size in males (SVL 37.5–41.3 mm vs. 34.9–37.2 mm), the absence of circummarginal grooves on disc of first finger (vs. presence), and different dorsal colour pattern (light grey with scattered small, indistinct greenish dots vs. green with distinct brown mottling); from A. aniqiaoensis Dong, Rao & Lü, 2005 by having a larger size in females (SVL 61.5–62.5 mm vs. 52.0 mm), tympanum visible (vs. invisible), the absence of circummarginal grooves on disc of first finger (vs. presence), and different dorsal colour pattern (light grey with scattered small, indistinct greenish dots vs. green); from A. archotaphus Inger & Chanard, 1997 by the absence of circummarginal grooves on disc of first finger (vs. presence), the absence of outer metatarsal tubercle on the hindlimbs (vs. presence), dorsolateral fold distinct (vs. weak or absence), and different dorsal colour pattern (light grey with scattered small, indistinct greenish dots vs. olive green, with irregularly distributed small brown spots); from A. bellulus Liu, Yang, Ferraris & Matsui , in Liu, Yang, Ferraris, Matsui & Price (2000), by having a smaller size (SVL 37.5–41.3 mm in males, 61.5–62.5 mm in females vs. 45.9–50.1 mm in males, 63.6 mm in females, respectively), the presence of vocal sac in males (vs. absence), and different dorsal colour pattern (light grey with scattered small, indistinct greenish dots vs. olive green with brown spots); from A. chakrataensis Ray, 1992 by having a larger size in females (SVL 61.5–62.5 mm vs. 55.0 mm), head longer than wide (vs. head wider than long), and different dorsal colour pattern (light grey with scattered, indistinct greenish dots vs. reddish brown); from A. chunganensis ( Pope, 1929) by having a larger size in females (SVL 61.5–62.5 mm vs. 44.0–54.0 mm), the absence of circummarginal grooves on disc of grooves on disc of first finger (vs. presence), and different dorsal colour pattern (light grey with scattered small, indistinct greenish dots vs. reddish brown); from A. daorum (Bain et al.) by having a larger size (SVL mean ± SD 39.5 ± 1.5 mm [n = 7] vs. 35 ± 1.5 mm [n = 8] in males; 62.1 ± 0.55 mm [n = 3] vs. 50 ± 1.2 mm [n = 8] in females), the absence of circummarginal grooves on disc of grooves on disc of first finger (vs. presence), the presence of two oblique vomerine ridges (vs. absence), and different dorsal colour pattern (light grey with scattered small, indistinct greenish dots vs. green with black spots). Amolops truongi , new species, differs from A. deng Che, Jiang, Yan & Zhang, 2020 by having a smaller size (SVL 37.5–41.3 mm in males, 61.5–62.5 mm in females vs. 50.3–57.6 mm in males, 68.5–72.0 mm in females), the absence of circummarginal grooves on disc of grooves on disc of first finger (vs. presence), and different dorsal colour pattern (light grey with scattered small, indistinct greenish dots vs. brown); the new species differs from A. gerbillus ( Annandale, 1912) by having a smaller size in males (SVL 37.5–41.3 mm vs. 66.0 mm), tympanum visible (vs. invisible), and different dorsal colour pattern (light grey with scattered small, indistinct greenish dots vs. reddish brown); from A. iriodes (Bain & Nguyen) by having a smaller size in females (SVL 61.5–62.5 mm vs. 63.0 mm), the absence of circummarginal grooves on disc of grooves on disc of first finger (vs. presence), and different dorsal colour pattern (light grey with scattered small, indistinct greenish dots vs. iridescent light green with some black spots); from A. kohimaensis Biju, Mahony & Kamei, 2010 by having a smaller size in males (SVL 37.5–41.3 mm vs. 42.8–48.6 mm) and different dorsal colour pattern (light grey with scattered small, indistinct greenish dots vs. brown); from A. mengdingensis Yu, Wu & Yang, 2019 by having a smaller size in females (SVL 61.5–62.5 mm vs. 64.3 mm), the absence of circummarginal grooves on disc of grooves on disc of first finger (vs. presence), and different dorsal colour pattern (light grey with scattered small, indistinct greenish vs. green); from A. mengyangensis Wu & Tian, 1995 by the presence of two oblique vomerine ridges (vs. absence), the absence of circummarginal grooves on disc of grooves on disc of first finger (vs. presence), and different dorsal colour pattern (light grey with scattered small, indistinct greenish dots vs. olive brown); from A. monticola ( Anderson, 1871) by having a smaller size in females (SVL 61.5–62.5 mm vs. 66.0–75.0 mm), head longer than wide (vs. head as wide as long), the presence of dorsolateral fold (vs. absence), and the absence of circummarginal grooves on disc of grooves on disc of first finger (vs. presence); the new species differs from A. nyingchiensis Jiang, Wang, Xie, Jiang & Che, 2016

by having a smaller size in males (SVL 37.5–41.3 mm

±

SD

0.15

± 0.06 ± ± 0.02 0.01 ± 0.01 ± ± 0 ± 0 ± 0.01 0.01 ± 0 ± 0.01 ± 0.01 ± vs. 48.5–58.3 mm), the presence of vocal sac in males

mean 1.9 2.2 0.47 0.35 0.32 0.15 0.15 0.37 0.87 0.37 0.65 1.78 (vs. absence), and the absence of circummarginal grooves on disc of grooves on disc of first finger (vs. presence);

Max 2.0 2.3 0.48 0.36 0.33 0.15 0.15 0.38 0.88 0.37 0.66 1.79 from A. putaoensis Gan, Qin, Lwin, Li, Quan, Liu & Yu ,

– – – – – – – – – – – – –

Min 1.7 2.2 0.32 0.15 0.15 0.36 0.87 0.36 0.64 0.45 0.35 1.77 2020 by the absence of circummarginal grooves on disc of grooves on disc of first finger (vs. presence), head longer than wide (vs. head wider than long), and different dorsal

4996

IEBR.

2016.343

SL Paratype Female 1.9 2.2 0.45 0.36 0.32 0.15 0.15 0.36 0.88 0.37 0.64 1.79

colour greenish pattern dots vs

(

.

light brown grey with with dark spots scattered

); from small

A. tuanjieensis

, indistinct

Gan, Yu & Wu, 2020 by having a larger size in females

2022.06 2016.340

Paratype Female 1.7 2.2 0.48 0.35 0.33 0.15 0.15 0.37 0.87 0.36 0.65 1.77 (circummarginal SVL 61.5–62.5 grooves mm vs on. 56.8 disc –60.7 of grooves mm), the on disc absence of first of

.

ZVNU SL. finger and outer metatarsal tubercle on the hindlimbs (vs. presence), and different dorsal colour pattern (light grey

2022.05

with scattered small, indistinct greenish dots vs. green with

2016.339 Paratype.

ZVNU. SL Female 2.0 2.3 0.48 0.35 0.32 0.15 0.15 0.38 0.87 0.37 0.66 1.77 near dark sacrum brown stippling); from A and. vitreus large (Bain brown, Stuart spots that & Orlov concentrate, 2006)

by the absence of circummarginal grooves on disc of first finger (vs. presence), the absence of outer metatarsal tubercle

SD

± 0.2 0.1

0.01 ± 0 0.01 0.01 ± 0 ± 0.01 0.02 0.01 0.03 0.04 on the hindlimbs (vs. presence), and different dorsal colour mean

± 1.1 ± 1.5 ± 0.45 0.36 ± 0.33 0.16 0.16 ± 0.4 ± 0.89 ± 0.38 ± 0.69 ± 1.87 pattern (light grey with scattered small, indistinct greenish dots vs. green with dark brown stippling and large brown

Max

1.4 1.7

0.47 0.36 0.34 0.16 0.42 0.91 0.39 0.72 1.92 spots that concentrate near sacrum); from A. wenshanensis

– – – – – – – 0.16 – – – – – Yuan, Jin, Li, Stuart & Wu, 2018 by having a larger size

Min 0.8 1.4 0.44 0.35 0.31 0.15 0.38 0.85 0.37 0.65 1.82 in females (SVL 61.5–62.5 mm vs. 43.7–45.6 mm), the absence of circummarginal grooves on disc of first finger

4994

IEBR SL

2016.348

.

Paratype Male 0.8 1.5 0.47 0.36 0.32 0.16 0.16 0.41 0.90 0.38 0.72 1.92 (with vs. present scattered), and small different, indistinct dorsal greenish colour dots pattern vs. light (light green grey in A. wenshanensis ) ( Tables 2, 3).

IEBR

4993

.

2016.346

SL. Paratype Male 0.9 1.5 0.46 0.36 0.32 0.15 0.16 0.40 0.87 0.38 0.70 1.85 DISCUSSION

2022.02

Over the last five years, 24 additional species have been

2016.342 Paratype.

ZVNU. SL Male 1.4 1.6 0.46 0.36 0.33 0.16 0.16 0.40 0.90 0.37 0.70 1.93 of described the species within, i the.e., genus A. ottorum Amolops , A. (Frost shihaitaoi, 2022,). and Three A.

wenshanensis were either discovered or recorded in Vietnam ( Pham et al., 2019; 2020; Wang et al., 2022). Our discovery,

IEBR

4995

. SL

2016.349

Paratype Male 0.8 1.4 0.45 0.35 0.34 0.15 0.16 0.41 0.90 0.39 0.69 1.82 the the Son same fourth La Province period new species, brings to six documented, the and number in Vietnam of in Amolops the to country 16. species Although within in pairwise genetic distance shows slight divergence (3.3–3.4%)

.

2022.03

ZVNU. SL 2016.347 Paratype Male 1.2 1.7 0.45 0.36 0.33 0.15 0.16 0.42 0.91 0.37 0.72 1.83 between on species a fragment significantly the new of species the differs mitochondrial and from Amolops A. compotrix ND compotrix 2 gene in, terms the based new of morphology. Specifically, the new species can be clearly distinguished from A. compotrix by having a larger size;

2022.04

ZVNU

.

SL.

2016.352 Paratype Male 1.2 1.6 0.44 0.36 0.34 0.16 0.16 0.38 0.85 0.38 0.65 1.85 a grooves lower ratio on disc of TD of first to ED finger; the and absence outer metatarsal of circummarginal tubercle on the hindlimbs (vs. presence); relative tympanum diameter of males small compared to females (vs. equal or near equal),

2022.01 2016.344

Holotype Male 1.2 1.5 0.45 0.35 0.31 0.15 0.16 0.40 0.89 0.37 0.69 1.86 and indistinct dorsal greenish colour pattern dots vs (. light bluish grey green with) (Table scattered 4). small,

.

ZVNU SL. Son La currently harbours three species of the Amolops monticola group, including A. cf. compotrix , A. truongi , new

Character HTD MTTi SVL AG / / HL SVL / SVL HW HD / SVL / SVL SE HL / ED ED SE / TD ED / / SVL FLL

SVL / HLL of species record Amolops , is and around A compotrix . vitreus more. Pham in than Son (700 2016 La km) Province reported from three. the However occurrence locations, the,

namely Khammouane Province in Lao PDR and Thua Thien Hue and Kon Tum provinces in Vietnam, where the species is found ( Bain et al., 2006). In terms of morphology, the population in Son La only superficially resembles A. compotrix , i.e., similarity in body colourations and HL/HW and TD/ED ratios, but the two taxa differ in female size and SL/HL and ED/SL ratios. Moreover, samples of the population have not been sequenced for comparison with other species in the group. Thus, the population from Son La Province, which may represent a new taxon of Amolops , requires further morphological and molecular analyses to confirm its taxonomic status.

Figures

Fig. 3. Dorsolateral (A) and ventral (B) views of the male holotype (ZVNU.2022.01) of Amolops truongi, new species, in life. Photo A. V. Pham.

Fig. 2. Phylogram based on the single-model Bayesian analysis. Number above branches are ML ultrafast bootstrap/MP bootstrap values, respectively, and those under branches are Bayesian posterior probabilities (>50%). Asterisks and dashes represent fully supported (100% for BP and UFB and 1.0 for PP) and unsupported nodes, respectively.

Fig. 1. Distribution of the genus Amolops in Son La Province, Vietnam: 1, A. cf. compotrix in Co Ma Commune, Thuan Chau District; 2, A. vitreus in Province in Co Ma Commune, Thuan Chau District; 3, A. ottorum in Ngoc Chien Commune, Muong La District; 4, A. truongi, new species, in Phieng Ai Commune, Muong La District; 5, A. ricketti in Muong Bang Commune, Phu Yen District; and 6, A. cremnobatus in Tan Xuan Commune, Van Ho District.

Fig. 7. A, Dorsolateral view of the adult male ofAmolops compotrix, photo C. T. Pham from Thua Thien Hue Province, Vietnam; B, the adult male and female of Amolops cucae, photo, T. Q. Nguyen from Lao Cai Province, Vietnam.