New records and an updated checklist of amphibians from Lai Chau Province, Vietnam

We provide a checklist of 45 species of amphibians from Lai Chau Province, northwestern Vietnam. Thirteen of species are recorded for the first time from Lai Chau Province; these include four species of Dicroglossidae, four species of Megophryidae, three species of Ranidae, and two species of Rhacophoridae. We also provide descriptions of the newly recorded species. The amphibian fauna of Lai Chau Province is of high conservation concern, with three species endemic to Vietnam, 10 species listed in the IUCN Red List, and two species listed in the Red Data Book of Vietnam.

As a result of our recent field survey in Lai Chau Province in May 2020, we provide an updated checklist of 45 species of amphibians, including 13 new records from the province.

Methods
Sampling. The field survey was conducted by Cuong The Pham, Chung Van Hoang, Anh Van Pham, Tien Quang Phan, and Nenh Ba Sung on 11-23 May 2020 in Sin Ho and Tam Duong districts, Lai Chau Province (Fig. 1). The main habitat type was secondary forest of medium-sized and small hardwoods mixed with shrubs and bamboo at elevations between 1100 and 2500 m above sea level (a.s.l.) (Fig. 2). The coordinates (WGS 84) were recorded using a GPS Garmin 60CX receiver.
Specimens were collected between 19:00 h and 24:00 h. After photographing in life, specimens were euthanized in a closed vessel with a piece of cotton wool containing ethyl acetate (Simmons 2002), fixed in 80% ethanol for 5 h, and then later transferred to 70% ethanol for permanent storage. Tissue samples were preserved separately in 70% ethanol prior to fixation. Specimens referred to in this paper are deposited in the collections of the Institute of Ecology and Biological Resources (IEBR), Hanoi, Vietnam.
Morphological examination. Measurements were taken on preserved specimens with digital calipers to the nearest 0.1 mm. The following abbreviations were used: SVL = snout-vent length, HL = head length (from the back of mandible to tip of snout), HW = maximum head width (across angles of jaws), RL = rostral length (from anterior corner of orbit to tip of snout), NS= distance from nostril to the tip of snout, EN = distance from anterior corner of orbit to the nostril, IND = internarial distance, IOD = interorbital distance, ED = eye diameter, UEW = maximum width of upper eyelid, DAE = distance between anterior corners of orbits, MN = posterior margin of mandible to nostril, MFE = posterior margin of mandible to anterior corner of orbit, MBE = posterior margin of mandible to posterior corner of orbit; DPE = distance between posterior corners of orbits, TYD = tympanum diameter, TYE = distance from anterior margin of tympanum to posterior corner of orbit, FLL = forearm length (from elbow to base of outer palmar tubercle), HAL = hand length (from base of outer palmar tubercle to tip of third finger), FL1-4 = Finger length I-IV, OPT = outer palmar tubercle length, IPT = inner palmar tubercle length, NPL = nuptial pad length, FeL = femur length (from vent to knee), TbL= tibia length (from knee to tarsus), TbW = maximum tibia width, FoL = foot length (from tarsus to the tip of fourth toe), TL1-5 = toe length I-V, IMT = inner metatarsal tubercle length. For the webbing formula, we followed Glaw and Vences (2007). Sex was determined by examination of the presence of nuptial pads and gonadal inspection.
Coloration in life: dorsal surface of head, body and upper limbs brownish purple with dark brown mottling on back; ventral brown with white pattern; flanks with dark brown spotting and white pustules. Tips of digits, metacarpal and metatarsal tubercles white. Distribution. In Vietnam, this species has been reported from Lao Cai, Son La and Yen Bai provinces (Nguyen et al. 2009Frost 2020). Elsewhere, the species is known from Wenshan, Pingbian, and Yunnan provinces of China (Frost 2020). ; collected from the bank of a small, rocky stream, surrounding habitat covered by mixed secondary forest of medium-sized to large hardwoods and bamboo; 1 ♂; IEBR 4769. Identification. Morphological characteristics of the specimens from Lai Chau were consistent with those in the descriptions of , Fei et al. (2010), and Luong et al. (2019). Size large (SVL 82.8-89.9 mm); head as wide as long (HW 32.3-39.1 mm, HL 33.1-39.8 mm); snout pointed, longer than eye diameter (RL 10.1-11.5 mm, ED 9.5-10.9 mm); nostril oval, laterally positioned, at the midway between eye and tip of snout (NS 4.9-6.4 mm, EN 4.8-6.5 mm); canthus sharp, loreal region concave; eye large (ED 9.5-10.9 mm), tympanum indistinct; supratympanic fold distinct, vomerine teeth absent; tongue heart-shaped, slightly notched posteriorly. Arm long , relative lengths of fingers I<II<IV<III, tips of fingers round; fingers free of webbing; subarticular tubercles indistinct; two round palmar tubercles, inner larger and more prominent. Thigh slender, long (FeL 40.0-44.9 mm); tibia approximately four times longer than wide (TbL 42.9-50.1 mm, TW 10.0-12.6 mm); relative lengths of toes I<II<V<III<IV; webbing formula I1-1½II1-2III2-3IV3-1½V; tips of toes slightly swollen; toes with dermal fringes; subarticular tubercles absent; inner metatarsal tubercle present, oval; outer metatarsal tubercle absent; tibio-tarsal articulation reaching between eye and nostril when leg adpressed along body. Skin: dorsal surface smooth; supratympanic fold present, from posterior edge of eye to axilla; flanks smooth; ventral surface smooth; outer edge of the eyelid without a horn-like tubercle.
Coloration in life: dorsal surface yellowish brown, without black marking; loreal and supratympanic fold edged in black below; upper lip yellow; flanks yellowish brown; ventral surface brown with yellow pattern. Distribution. In Vietnam, this species has been reported from Lao Cai and Son La provinces (Luong et al. 2019). Elsewhere, the species is known from Yunnan Province of China (Frost 2020).
Coloration in life: dorsal surface and lateral sides of head, body, forelimbs and hindlimbs grey; a dark brown triangular marking with a light central blotch between eyes; throat, chest and anterior part of belly primarily brown; belly cream with dark brown patterns; pectoral glands white. Distribution. In Vietnam, this species has been reported from Lao Cai, Ha Giang, and Vinh Phuc provinces (Nguyen et al. 2009(Nguyen et al. , 2016Luong et al. 2018). Elsewhere, the species is known from Yunnan and Guangxi provinces, China (Frost 2020). Tapley Phan, and N.B. Sung leg.; collected from the bank of a rocky stream, surrounding habitat covered by secondary forest of medium-sized and small hardwoods and shrubs; 2 ♂, 1 ♀; IEBR 4775-4777. Identification. Morphological characteristics of the specimens from Lai Chau were consistent with those in the description of Tapley et al. (2017). Size small (SVL 28.6-30.9 mm in males and SVL 29.3 mm in the female); head narrower than long (HW 9.6-11.3 mm, HL 10.2-11.5 mm in males; HW 12.8 mm, HL 13.4 mm in the female); snout round in dorsal view, as long as eye diameter in males (RL 3.5-3.9 mm, ED 3.0-3.9 mm); longer than eye diameter in the female (RL 4.8 mm, ED 4.1 mm); nostril oval, laterally positioned, closer to the tip of snout than to the eye (NS 1.3-1.9 mm, EN 1.6-2.2 mm in males; NS 2.2 mm, EN 2.5 in the female); canthus rostralis angular, eye large (ED 3.0-3.9 mm in males; ED 4.1 mm in the female), tympanum distinct (TYD 1.5-1.7 mm in males; TYD 2.0 mm in the female); supratympanic fold narrow, vomerine teeth present; tongue moderately large and not clearly notched posteriorly. Arm short and stocky (FLL 5.6-7.0 mm in males; FLL 7.4 mm in the female), relative lengths of fingers I<II<IV<III, tips of fingers round; fingers free of webbing; fingers without lateral fringes, subarticular tubercles absent; inner metatarsal tubercle present; outer metatarsal tubercle absent. Thigh relatively short and stocky (FeL 13.4-15.3 mm in males; FeL 18.3 mm in the female); tibia approximately seven times longer than wide (TbL 15.6-17.1 mm, TW 2.2-3.0 mm in males; TbL 21.7 mm, TbW 3.1 mm in the female); tips of toes round; relative lengths of toes I<II<V<III<IV; toes free of webbing; subarticular tubercles absent; inner metatarsal tubercle present; outer metatarsal tubercle absent; tibio-tarsal articulation reaching to the nostril when leg adpressed along body. Skin: dorsal surface of body, limbs, and lateral surface of head weakly granular; flanks with small, scattered tubercles; chest, belly, and ventral surfaces of limbs smooth.
Coloration in life: dorsal surface yellow-brown, mostly with black mottling or marbling, sometimes with brownish vertebral stripe; lower region of flanks brownish; upper limbs with brown transversal bands; throat, pectoral region, belly, and outer edges of limbs with black mottles. Distribution. In Vietnam, this species has been reported from Cao Bang, Ha Giang, and Dien Bien provinces in the north southwards to Quang Binh Province (Frost 2020). Elsewhere, the species is known from Laos and Yunnan and Guangxi provinces, China (Frost 2020).
Coloration in life: dorsal surface of head and body grey-brown; dorsolateral fold indicated by a thin black line; upper lip dark brown, lower region of flanks brownish with black spots; upper limbs brown with black bands; chest, belly and under limbs cream.
Distribution. In Vietnam, this species has been reported from Lao Cai, Son La, and Nghe An provinces (Nguyen et al. 2009;Pham et al. 2012). Elsewhere, the species is known from Yunnan Province of China and northwestern Thailand (Frost 2020).

Nanorana yunnanensis (Anderson, 1879)
Yunnan Paa Frog Figure  ; collected from the water near a waterfall of the a rocky stream, surrounding habitat covered by secondary forest of medium-sized and large hardwoods; 3 ♂, 1 ♀; IEBR 4793-4796. Identification. Morphological characteristics of the specimens from Lai Chau were consistent with those in the descriptions of Liu (1950) and Fei et al. (2010). Size large (SVL 83.7-110.6 mm in males, SVL 73.1 mm in the female); head wider than long (HW 32.0-42.7 mm, HL 31.0-39.5 mm in males; HW 30.0 mm, HL 28.6 mm in the female); snout round, longer than eye diameter (RL 11.0-14.2 mm, ED 7.8-9.3 mm in males; RL 10.1 mm, ED 6.9 mm in the female); nostril oval, laterally positioned, closer to the eye than to tip of snout (NS 6.8-8.8 mm, EN 4.0-5.8 mm in males; NS 6.5 mm, EN 3.9 mm in the female); canthus rostralis indistinct, eye large (ED 7.8-9.3 mm in males; ED 6.9 mm in the female), tympanum hidden; supratympanic fold distinct, vomerine teeth present; tongue notched posteriorly. Arm short (FLL 15.4-21.6 mm in males; FLL 12.7 mm in the female), relative lengths of fingers I<II<IV<III, tips of fingers obtuse; fingers free of webbing; subarticular tubercles distinct, formula 1, 1, 2, 2; two palmar tubercles, inner larger and more prominent. Thigh short (FeL 37.8-52.2 mm in males; FeL 36.1 mm in the female); tibia approximately three times longer than wide (TbL 42.2-55.0 mm, TW 14.7-19.7 mm in males; TbL 37.1 mm, TW 10.9 mm in the female); tips of toes round; relative lengths of toes I<II<V<III<IV; webbing formula I0-½II½-0III0-0IV0-0V; subarticular tubercles distinct, formula 1, 1, 2, 3, 2; inner metatarsal tubercle present, oval; outer metatarsal tubercle absent; tibio-tarsal articulation reaching to the shoulder when leg adpressed along body. Skin: dorsal surface of head and body granular, with numerous small warts on the back, some elongate, these granules and warts bearing black horny spinules. Ventral surface smooth, horny spines forming two patches on the chest and throat, and more dense patches on the inner metacarpal tubercle and on the upper side of the first and second fingers.
Coloration in life: dorsal surface of head and body brown, with indistinct black spots; limbs with dark brown cross bars; upper hind limbs brown with black horny spinules; ventral surface cream with white spots. Adult males with black horny spines on chest, throat, inner metacarpal tubercle and on the upper side of the first and second fingers. Distribution. In Vietnam, this species has been reported from Lao Cai, Son La, Cao Bang, and Nghe An provinces (Nguyen et al. 2009;Frost 2020). Elsewhere, the species is known from Myanmar and Yunnan and Guizhou provinces of China (Frost 2020). (Bourret, 1937) Spiny Frog Figure  Sung leg.; collected from the water of a rocky stream, surrounding habitat covered by secondary forest of medium-sized and small hardwoods and shrubs; 1 ♂, 2 ♀; IEBR 4797-4799. Identification. Morphological characteristics of the specimens from Lai Chau were consistent with those reported by Hu et al. (2005) and Fei et al. (2010). Size large (SVL 106.4 mm in the male, SVL 86.0-86.7 mm in females); head wider than long (HW 42.7 mm, HL 40.7 mm in the male; HW 34.7-35.0 mm, HL 32.7-33.4 mm in females); snout round, longer than eye diameter (RL 15.0 mm, ED 9.9 mm in the male; RL 12.6-12.8 mm, ED 8.5-9.5 mm in females); nostril oval, laterally positioned, closer to the eye than to the tip of snout (NS 8.3 mm, EN 6.3 mm in the male; NS 6.6 mm, EN 6.1 mm in females); canthus rostralis indistinct, eye large (ED 9.9 mm in the male; ED 8.5-9.5 mm in females); tympanum indistinct; supratympanic fold distinct; vomerine teeth present; tongue notched posteriorly. Arm short (FLL 18.3 mm in the male; FLL 14.7-15.8 mm in females), relative lengths of fingers I<II<IV<III in the male and relative lengths of fingers I<II<IV=III in females, tips of fingers slightly swollen; fingers free of webbing; subarticular tubercles distinct, formula 1, 1, 1, 1; inner metatarsal tubercle present, oval; outer metatarsal tubercle absent. Thigh short (FeL 52.7 mm in the male, FeL 38.6-48.1 mm in females); tibia approximately three times longer than wide (TbL 59.1 mm, TW 20.5 mm in the male; TbL 46.8-47.0 mm, TW 12.8-15.0 mm in females); tips of toes swollen; relative lengths of toes I<II<V<III<IV; webbing complete; subarticular tubercles distinct, formula 1, 1, 2, 3, 2; inner metatarsal tubercle present, round; outer metatarsal tubercle absent; tibio-tarsal articulation reaching to the shoulder when leg adpressed along body. Skin: dorsal surface of head and body granular, back with large oval warts intermixed with small tubercles; upper surface of fore and hind limbs granular; small black spinule present on fingers I and II during breeding season; venter smooth.

Quasipaa verrucospinosa
Coloration in life: dorsal surface of head dark brown; lips and upper limbs with black bars; deep-brown upper surface of limbs; throat with black marbling; belly cream with black pattern (Hu et al. 2005;Fei et al. 2010). Distribution. In Vietnam, this species has been reported from northern to central Vietnam (Nguyen et al. 2009). Elsewhere, the species is known from Yunnan Province of China and Longcheng of Laos (Frost 2020). Sung leg.; collected from the ground near a waterfall of a rocky stream, surrounding habitat covered by mixed secondary forest of bamboo, small to medium-sized hardwoods and shrubs; 8 ♂, 1 ♀; IEBR 4800-4808. Identification. Morphological characteristics of the specimens from Lai Chau were consistent with those in the descriptions of Bourret (1942) and Bain et al. (2003). Males smaller than female (SVL 44.2-45.6 mm in males, SVL 96.0 mm in the female); head narrower than long (HW 14.0-15.0 mm, HL 17.0-19.0 mm in males; HW 31.0 mm, HL 37.0 mm in the female); snout round, longer than eye diameter (RL 6.7-7.3 mm, ED 5.9-6.3 mm in males; RL 13.8 mm, ED 11.8 mm in the female); nostril oval, laterally positioned, closer to the tip of snout than to eye (NS 2.5-3.4 mm, EN 4.0-4.7 mm in males; NS 6.0 mm, EN 8.5 mm in the female); canthus rostralis distinct, eye large (ED 5.9-6.3 mm in males; ED 11.8 mm in the female), tympanum distinct (TYD 3.8-4.5 mm in males; TYD 5.0 mm in the female); supratympanic fold indistinct, vomerine teeth present; tongue deeply notched posteriorly; males with vocal sacs. Arm slender (FLL 8.6-11.1 mm in males and FLL 16.2 mm in the female), relative lengths of fingers I<II<IV<III, tips of fingers enlarged into discs; fingers free of webbing; subarticular tubercles distinct, formula 1, 1, 2, 2; inner metatarsal tubercle present, round; outer metatarsal tubercle absent. Thigh slender (FeL 23.4-26.2 mm in males, FeL 57.4 mm in the female); tibia approximately seven times longer than wide in males (TbL 27.8-30.6 mm, TW 3.3-4.7 mm) and tibia approximately six times longer than wide in the female (TbL 65.0 mm, TW 10.2 mm); tips of toes enlarged into discs; relative lengths of toes I<II<V<III<IV in males and I<II<III<V<IV in the female; webbing complete; subarticular tubercles distinct, formula 1, 1, 2, 3, 2; inner metatarsal tubercle present, elongate; outer metatarsal tubercle absent; tibio-tarsal articulation reaching beyond tip of snout when leg adpressed along body. Skin: dorsal surface of head and body smooth; flank with small tubercles, dorsolateral fold absent; ventral surface smooth.
Coloration in life: dorsum green with or without black spots, lateral side of head and flanks brownish grey, lips white; hind limbs with distinct black bars; webbing dark grey; throat and chest cream or whitish; ventral surface whitish. Distribution. In Vietnam, this species has been reported from Bac Kan, Lang Son, Vinh Phuc, Quang Ninh and Lam Dong provinces (Nguyen et al. 2009). Elsewhere, the species has been reported from northeastern India and Myanmar to southern China (Frost 2020).
Coloration in life: dorsum green with large brown spots; dorsal surface of limbs brown with black cross bars; flank brown with black spots; belly and throat cream, marbled with brown. Distribution. In Vietnam, this species has been reported from Lao Cai, Ha Giang, and Dien Bien provinces (Nguyen et al. 2009;Frost 2020). Elsewhere, the species is known Yunnan and Guangxi provinces of China, northern Laos, and northeastern Myanmar (Frost 2020).
Coloration in life: dorsal surface of head and body brown, with or without black spots; outer edge of glandular dorsolateral fold blackish; limbs with black cross bars; throat and chest cream with dark brown spots; belly olive. Distribution. In Vietnam, this species has been reported from northern Vietnam: Lao Cai, Cao Bang to Thua Thien Hue provinces (Nguyen et al. 2009). Elsewhere, the species is known from Yunnan Province of China, Laos, and western and northwestern Thailand (Frost 2020).
Coloration in life: dorsum reddish brown with or without small black spots; large black blotches on axilla and flanks present; ventral surface yellowish; webbing of fingers and toes reddish orange. Distribution. In Vietnam, this species has been reported from Lao Cai, Ha Tinh, Quang Binh, Quang Tri, Thua Thien Hue, Kon Tum, Gia Lai, Lam Dong, and Dong Nai provinces (Nguyen et al. 2009). Elsewhere, the species is known from northeastern India, Xizang, Yunnan, Guangxi and Hainan provinces of China, Myanmar, Laos, northern Thailand, and Cambodia (Frost 2020).

Zhangixalus duboisi (Ohler, Marquis, Swan & Grosjean, 2000)
Dubois' Whipping Frog Figure  Sung leg.; collected from the tree branches near a small stream, about 0.5 m above the ground, surrounding habitat covered by mixed secondary forest of bamboo, small to medium-sized hardwoods and shrubs; 2 ♂; IEBR 4821-4822.
Coloration in life: dorsal surface of head, body, and limbs green with large, dark, brown spots edged in black and some small white spots; flank and posterior surface of thigh white with dark brown marbling; belly greywhite with numerous small, medium-grey spots. Distribution. In Vietnam, this species was previously reported from Lao Cai, Son La and Ha Giang provinces (Nguyen et al. 2009;Ziegler et al. 2014). Elsewhere, the species is known from Yunnan Province, China (Frost 2020).
The amphibian fauna of Lai Chau Province is of high conservation concern as there are three known species to be endemic to Vietnam (Megophrys hoanglienensis, Gra cixalus sapaensis, and Tylototriton sparreboomi), 10 species listed in the IUCN Red List (2020) [EN]). Considering the vulnerability of the amphibian diversity found in this province, protecting and restoration of the natural habitat and conducting additional studies in this province are essential.