Morphological characters of the specimens from Ha Nam Province agreed well with the descriptions of Bourret (1942), Manthey and Grossmann (1997), Bain and Nguyen (2004) and Hecht et al. (2013): SVL 22.1 mm in male (n = 1) and 26.8 mm in female (n = 1); snout round, pronounced, longer than eye (RL 2.9 mm, ED 2.5 mm in male; RL 3.7 mm, ED 2.8 mm in female); interorbital distance 1.6–1.9 times broader than upper eyelid (UEW 1.6 mm, IOD 2.5 mm in male; UEW 1.7 mm, IOD 3.2 mm in female); tympanum invisible; vomerine teeth absent; tongue roundly spatulate and free at the rear half of its length; external vocal sac present in males. Fore-limb slender (HAL 10.4 mm in male and 10.9 mm in female); fingers free of webbing, with slightly developed discs. Hind-limb slender, tibia longer than thigh (TbL 13.4 mm, FL 11.3 mm in male; TbL 14.0 mm, FL 12.5 mm in female); toes with small discs, basally webbed; subarticular tubercle prominent; inner and outer metatarsal tubercles present; tibio-tarsal articulation reaching between eye and tip of snout. Dorsal skin with tiny tubercles on the dorsum and tibia; ventral skin smooth, cloacal region granular. Colouration in life: dorsal surface of head grey, dorsal surface of body brown; a grey stripe extending from eye to shoulder; limbs with dark transverse bars; ventral surface whitish (Figs 2, 3).

Figure 2.  

Microhyla butleri (adult male, IB A.6390).

Figure 3.  

Microhyla butleri (adult female, IB A.6391).

In Vietnam, this species is known from Lao Cai and Ha Giang Provinces in the north, southwards to Dong Nai Province and Ho Chi Minh City (Nguyen et al. 2009, Hecht et al. 2013). Elsewhere, this species is known from China, Myanmar, Laos, Thailand, Cambodia, Indonesia, Malaysia and Singapore (Frost 2025).

Specimens of Microhyla butleri were found on the ground near a small puddle between 20:15 h and 20:45 h. Males were recorded calling at the site and tadpoles were detected in temporary water puddles. The surrounding habitat was a mixed secondary forest of small hardwood and shrubs.

Conservation status. LC (Least Concern) (IUCN 2025).

Morphological characters of the specimens from Ha Nam Province agreed well with the descriptions of Bourret (1942), Manthey and Grossmann (1997), Hecht et al. (2013) and Hoang et al. (2022): SVL 19.5 mm in male (n = 1) and 23.7 mm in female (n = 1); snout profile obtusely pointed, somewhat longer than eye (RL 3.0 mm, ED 2.5 mm in male; RL 3.7 mm, ED 2.2 mm in female); interorbital distance 1.6–1.9 times broader than upper eyelid (UEW 1.3 mm, IOD 2.5 mm in male; UEW 1.8 mm, IOD 2.8 mm in female); tympanum invisible; vomerine teeth absent; tongue roundly spatulate and free at the rear half of its length; external vocal sac present in males. Fore-limb slender (HAL 8.5 mm in male and 9.8 mm in female); fingers free of webbing and tips not swollen. Hind-limb slender, tibia longer than thigh (TbL 11.5 mm, FL 9.9 mm in male; TbL 13.2 mm, FL 11.9 mm in female); toe tips round, not swollen, webbed at base; subarticular tubercle present; inner and outer metatarsal tubercles present; tibio-tarsal articulation reaching tip of snout. Dorsal skin smooth, dorsolateral edges not sharp; ventral skin smooth. Colouration in life: Dorsal surface of head and body pale grey, with a white stripe from tip of snout to cloaca and a small dark spot in the centre of the back; lateral side of head and flank dark brown to black; anterior part of thighs, cloacal region and lower parts of feet black; limbs with thin transverse bars; ventral surface white to grey (Figs 4, 5).

Figure 4.  

Microhyla heymonsi (adult male, IB A.6392).

Figure 5.  

Microhyla heymonsi (adult female, IB A.6393).

In Vietnam, this species is known from Lao Cai and Ha Giang Provinces in the north, southwards to Kien Giang and Ca Mau Provinces (Nguyen et al. 2009, Hecht et al. 2013). Elsewhere, this species is known from China, Cambodia, Laos, Myanmar, Thailand and Malaysia (Frost 2025).

Specimens of Microhyla heymonsi were found on the ground near a small puddle or near small streams between 20:00 h and 21:30 h. Males were recorded calling at the site and tadpoles were observed in temporary water puddles. The surrounding habitat was a mixed secondary forest of small hardwood and shrubs.

Conservation status. LC (Least Concern) (IUCN 2025).

Morphological characters of the specimens from Ha Nam Province agreed well with the description of Hasan et al. (2014): SVL 21.8 mm in male (n = 1) and 26.4 mm in female (n = 1); snout round, longer than eye (RL 3.0 mm, ED 2.0 mm in male; RL 3.6 mm, ED 2.5 mm in female); interorbital distance 1.5–1.8 times broader than upper eyelid (UEW 1.4 mm, IOD 2.5 mm in male; UEW 2.0 mm, IOD 3.0 mm in female); tympanum invisible; vomerine teeth absent; tongue roundly spatulate and free at the rear half of its length; external vocal sac present in males. Fore-limb slender (HAL 8.0 mm in male and 9.4 mm in female); fingers free of webbing and tips not swollen. Hind-limb slender, tibia longer than thigh (TbL 12.0 mm, FL 9.5 mm in male; TbL 12.1 mm, FL 10.0 mm in female); toe tips round, not swollen, webbed at base; subarticular tubercle present; inner and outer metatarsal tubercles present; tibio-tarsal articulation reaching behind the eye. Dorsal skin smooth, dorsolateral ridges discontinuous; ventral skin smooth. Colouration in life: dorsal surface of head and body grey with a dark X-shaped mark on the dorsum, arising from the eyes to the groin; limbs with dark transverse bars; ventral surface whitish, throat and chest mottled with dark brown (Figs 6, 7).

Figure 6.  

Microhyla mukhlesuri (adult male, IB A.6394).

Figure 7.  

Microhyla mukhlesuri (adult female, IB A.6395).

In Vietnam, this species is known from Lao Cai and Dien Bien Provinces in the north, southwards to Quang Nam Province (Frost 2025). Elsewhere, this species is known from China, Myanmar, Laos, Cambodia, Thailand, India, Bangladesh and Malaysia (Frost 2025).

Specimens of Microhyla mukhlesuri were found on the ground near a small puddle between 20:30 h and 21:00 h. Males were recorded calling at the site and tadpoles were detected in temporary water puddles. The surrounding habitat was a mixed secondary forest of small hardwood and shrubs.

Conservation status. LC (Least Concern) (IUCN 2025).

Morphological characters of the specimens from Ha Nam Province agreed well with the descriptions of Bourret (1942), Taylor (1962) and Manthey and Grossmann (1997): SVL 29.2 mm in male (n = 1) and 37.1 mm in female (n = 1); snout obtusely point, slightly pronounced, longer than eye (RL 4.2 mm, ED 3.4 mm in male; RL 5.2 mm, ED 3.8 mm in female); interorbital distance 1.9–2.2 times broader than upper eyelid (UEW 1.6 mm, IOD 3.5 mm in male; UEW 2.4 mm, IOD 4.5 mm in female); tympanum invisible; vomerine teeth absent; tongue roundly spatulate and free at the rear half of its length; external vocal sac present in males. Fore-limb slender (HAL 11.8 mm in male and 13.2 mm in female); fingers free of webbing and tips not swollen. Hind-limb slender, tibia longer than thigh (TbL 18.5 mm, FL 15.6 mm in male; TbL 21.5 mm, FL 17.6 mm in female); toe tips round, not swollen, toes almost 1/2 webbed, webbing formula: I1/2–2II1–3III2–3½IV31/3–2V; subarticular tubercle present; inner and outer metatarsal tubercles present; tibio-tarsal articulation reaching tip of snout. Dorsal skin with a few scattered small tubercles; ventral skin smooth; cloacal region granular. Colouration in life: dorsum light brown, with a dark brown Λ-shaped pattern on the back, containing several dark and light lines, outer part bordered by several light lines; canthus rostralis and flanks dark brown; limbs with transverse bars; groin and anterior part of thigh yellow; ventral surface whitish yellow, chin and throat with black marbling (Figs 8, 9).

Figure 8.  

Microhyla pulchra (adult male, IB A.6396).

Figure 9.  

Microhyla pulchra (adult female, IB A.6397).

In Vietnam, this species is known from Lao Cai and Ha Giang Provinces in the north, southwards to Lam Dong and Dong Nai Provinces (Nguyen et al. 2009, Hecht et al. 2013). Elsewhere, this species is known from China, Myanmar, Laos, Thailand, Cambodia, Malaysia and Singapore (Frost 2025).

Specimens of Microhyla pulchra were found on the ground near a small puddle or near a pond between 20:00 h and 21:30 h. Males were recorded calling at the site and tadpoles were detected in temporary water puddles. The surrounding habitat was a mixed secondary forest of small hardwood and shrubs.

Conservation status. LC (Least Concern) (IUCN 2025).

Morphological characters of the specimens from Ha Nam Province agreed well with the descriptions of Liu et al. (2021) and Nguyen et al. (2024): SVL 22.3 mm in male (n = 1) and 27.5 mm in female (n = 1); head wider than long (HW 6.9 mm, HL 6.2 mm in male; HW 7.8 mm, HL 7.2 mm in female); snout abruptly round in dorsal view and slightly acuminate in profile, longer than eye (RL 3.3 mm, ED 2.5 mm in male; RL 3.9 mm, ED 2.9 mm in female); interorbital distance 1.9–2.3 times broader than upper eyelid (UEW 1.4 mm, IOD 3.2 mm in male; UEW 2.0 mm, IOD 3.8 mm in female); tympanum visible, round (TD 0.6 mm in male, 0.8 mm in female); vomerine teeth absent; tongue oval, with no notch at posterior tip; external vocal sac present in males. Fore-limb slender (HAL 11.9 mm in male and 14.2 mm in female); fingers free of webbing, tips round and not dilated; nuptial pad absent. Hind-limb slender, tibia longer than thigh (TbL 10.9 mm, FL 10.0 mm in male; TbL 12.5 mm, FL 11.8 mm in female); toe tips round and not dilated; webbing between toes absent; subarticular tubercle present; inner and outer metatarsal tubercles present; tibio-tarsal articulation reaching level of front of eye. Dorsal skin smooth, without dorsolateral fold, flanks and hind-limb with small tubercles; ventral skin smooth. Colouration in life: dorsal surface of head and body as well as upper arm golden, back with two indistinct parallel longitudinal grey stripes; lateral sides of head and body black; ventral side of body and limbs pinkish-brown, chin region brownish-black; chest and lateral region of belly with small and irregular white marbling (Figs 10, 11).

Figure 10.  

Micryletta hekouensis (adult male, IB A.6398).

Figure 11.  

Micryletta hekouensis (adult female, IB A.6399).

In Vietnam, this species is recently known from Hai Phong City and Ninh Binh Province (Nguyen et al. 2024, Frost 2025). Elsewhere, this species is only known from China (Frost 2025).

Specimens of Micryletta hekouensis were found on the ground near a small stream between 19:30 h and 21:30 h. Males were recorded calling at the site and tadpoles were observed in temporary water puddles. The surrounding habitat was a mixed secondary forest of small hardwood and shrubs.

Conservation status. Not evaluated (IUCN 2025).

Morphological characters of the specimens from Ha Nam Province agreed well with the description of Lyu et al. (2022): SVL 22.2 mm in male (n = 1) and 28.4 mm in female (n = 1); head longer than wide (HW 7.8 mm, HL 8.2 mm in male; HW 8.7 mm, HL 8.9 mm in female); snout round in dorsal view and profile, longer than eye (RL 3.5 mm, ED 2.8 mm in male; RL 4.0 mm, ED 3.0 mm in female); interorbital distance 1.5–2.0 times broader than upper eyelid (UEW 1.5 mm, IOD 3.0 mm in male; UEW 2.1 mm, IOD 3.1 mm in female); tympanum hidden, edge invisible; vomerine teeth absent; tongue round posteriorly; external vocal sac present in males. Fore-limb slender (HAL 8.5 mm in male and 11.3 mm in female); fingers free of webbing, tips round and not dilated; relative finger lengths II = I < IV < III; nuptial pad present in male. Hind-limb slender, tibia longer than thigh (TbL 11.0 mm, FL 10.1 mm in male; TbL 14.0 mm, FL 12.8 mm in female); relative lengths I < II < V < III < IV; toe tips round, dilated into round discs; toes fully webbed; subarticular tubercles present; inner and outer metatarsal tubercles present; tibio-tarsal articulation reaching at the posterior margin of supratympanic fold. Dorsal surface of body and limb rough, with large tubercles, flanks with tubercles; a faint fold across head between orbits; supratympanic fold distinct; dorsolateral fold absent; ventral surface with flat tubercles; a fold across breast; and dense granules on the ventral tarsi. Colouration in life: Dorsal surface greyish-brown with irregular black speckles; a narrow transverse dark bar between orbits; mid-dorsal stripe yellowish-brown, but indistinct; limbs with dark brown transverse bars; throat dark grey with white mottling; chest and belly uniform creamy white (Figs 12, 13).

Figure 12.  

Occidozyga lingnanica (adult male, IB A.6400).

Figure 13.  

Occidozyga lingnanica (adult female, IB A.6401).

In Vietnam, this species is known from Ninh Binh Province (unpublished data). Elsewhere, this species is known from China (Frost 2025).

Specimens of Occidozyga lingnanica were found on the ground near a small stream between 19:00 h and 21:30 h. Males were recorded calling at the site and tadpoles were detected in temporary water puddles. The surrounding habitat was a mixed secondary forest of small hardwood and shrubs.

Conservation status. Not evaluated (IUCN 2025).

Morphological characters of the specimens from Ha Nam Province agreed well with the descriptions of Sheridan and Stuart (2018) and To et al. (2025): SVL 40.1–40.4 mm in males (n = 2); head longer than wide (HW 14.2–14.8 mm, HL 16.5–17.1 mm); snout obtusely pointed in dorsal view, longer than eye (RL 6.9–7.1 mm, ED 6.2–6.5 mm); interorbital distance 1.3–1.5 times broader than upper eyelid (UEW 3.6–3.7 mm, IOD 4.9–5.2 mm); tympanum distinct, round, more than half eye diameter (TD 3.7–3.9 mm); vomerine teeth obliquely angled; tongue notched posteriorly; vocal sac openings near corner of jaw in males. Fore-limb slender (HAL 19.0–20.5 mm); fingers free of webbing, tips of fingers expanded into small discs with circum-marginal grooves, relative finger lengths IV < II < I < III; nuptial pad present in male. Hind-limb slender, tibia longer than thigh (TbL 22.0–24.0 mm; FL 19.0–21.6 mm); toe tips expanded into discs with circum-marginal grooves; webbing present, webbing formula: I1/2–3/4II0–1III0–1IV1–0V inner metatarsal tubercle elongate; tibio-tarsal articulation reaching between eye and nose. Dorsal skin finely granular; supratympanic fold distinct; dorsolateral fold distinct; throat, chest, belly and ventral surface of thigh smooth. Colouration in life: Dorsum reddish-brown, with a few dark brown mottling spots; lip white yellow; dorsal surface of fore-limb and hind-limb with dark crossbars; dorsolateral fold dark brown; flanks pale grey with dark brown spots; ventral surface slightly yellow, dark mottling on throat, less mottling on chest and underside of thighs (Fig. 14).

Figure 14.  

Hylarana nigrovittata (adult male, IB A.6402).

In Vietnam, this species is known from Bac Kan, Vinh Phuc, Thanh Hoa, Nghe An, Ha Tinh, Hue and Quang Nam Provinces (Sheridan and Stuart 2018, To et al. 2025). Elsewhere, this species is known from Laos (Frost 2025).

Specimens of Hylarana annamitica were found on the ground near two small streams between 19:00 h and 21:00 h. The surrounding habitat was a secondary forest of small hardwood and shrubs.

Conservation status. LC (Least Concern) (IUCN 2025).

Morphological characters of the specimen from Ha Nam Province agreed well with the descriptions of Bourret (1942) and Hecht et al. (2013): SVL 40.9 mm in male (n = 1); head longer than wide (HW 12.2 mm, HL 19.0 mm); snout obtusely pointed, pronounced, longer than eye (SL 6.6 mm, ED 5.6 mm); interorbital distance 1.3 times broader than upper eyelid (UEW 3.5 mm, IOD 4.4 mm); tympanum distinct, round, more than half eye diameter (TD 3.6 mm); vomerine teeth present; tongue notched posteriorly; external vocal sac present in males. Fore-limb slender (HAL 20.0 mm); fingers free of webbing, tips of fingers expanded into small discs, relative finger lengths II < I < IV < III; nuptial pad present in male. Hind-limb slender, tibia longer than thigh (TbL 27.2 mm; TbL 24.4 mm); toe tips expanded into discs; webbing present, webbing formula: I1/2–3/4II0–1III0–1IV1 3/4–0V; inner metatarsal tubercle elongate; outer metatarsal tubercle absent; tibio-tarsal articulation reaching beyond tip of snout. Dorsal skin with some small granules; a Λ-shaped fold between shoulders; some short, oblique dermal folds on limbs; supratympanic and dorsolateral folds distinct; throat, chest, belly and ventral surface of thigh smooth. Colouration in life: Dorsum brown; flank light brown; a small black stripe extending from nostril to eye; tympanum covered by a black lozenge; lateral side of limb with dark pattern; ventral surface cream; gular region marbled with white; thigh yellow (Fig. 15).

Figure 15.  

Rana johnsi (adult male, IB A.6404).

In Vietnam, this species is known from Lao Cai and Ha Giang Provinces in the north, southwards to Lam Dong and Dong Nai Provinces (Nguyen et al. 2009). Elsewhere, this species is known from China, Laos, Cambodia and Thailand (Frost 2025).

Specimen of Rana johnsi was found on the ground near a small stream at 21:00 h. The surrounding habitat was a secondary forest of small hardwood and shrubs.

Conservation status. LC (Least Concern) (IUCN 2025).

Morphological characters of the specimens from Ha Nam Province agreed well with the descriptions of Taylor (1962): SVL 30.5–32.4 mm in males (n = 2); head longer than wide (HW 10.5–11.5 mm, HL 11.3–11.9 mm); snout pointed anteriorly, as long as the eye (RL 5.0 mm, ED 5.0–5.3 mm); interorbital distance 1.2–1.4 times broader than upper eyelid (UEW 2.5–2.9 mm, IOD 3.5–3.7 mm); tympanum distinct, round, less than half eye diameter (TD 2.1–32.2 mm); vomerine teeth present; tongue notched posteriorly; external vocal sac present in males. Fore-limb slender (HAL 14.2–14.5 mm); fingers free of webbing, tips of fingers with enlarged discs; nuptial pad present in males. Hind-limb slender, tibia longer than thigh (TbL 16.0–17.0 mm; FL 14.0–15.6 mm); toe tips expanded into discs; webbing present, webbing formula: I1/2–1II0–1 1/2III0–1IV1–1/2V; inner metatarsal tubercle present; tibio-tarsal articulation reaching the eye. Skin on head, eyelids and occiput, dorsum with scattered tubercles; dermal fringes along outer edges of forearm and tarsus present; chin granular, chest nearly smooth; venter and lower part of flank granular. Colouration in life: Dorsal surface of head and body light brown with green marking, occiput with a dark green marking in triangular shape; chin cream with dark spots; throat, chest, venter and underside of limbs cream (Fig. 16).

Figure 16.  

Kurixalus bisacculus (adult male, IB A.6405).

In Vietnam, this species is known from Lao Cai Province in the north, southwards to Quang Binh Province (Yu et al. 2017, Frost 2025). Elsewhere, the species has been reported from Cambodia, China, Laos, Myanmar and Thailand (Frost 2025).

Specimens of Kurixalus bisacculus were found on a tree branch near a small stream between 19:45 h and 20:00 h. Males were recorded calling at the site. The surrounding habitat was a mixed secondary forest of small hardwood and shrubs.

Conservation status. LC (Least Concern) (IUCN 2025).

Morphological characters of the specimen from Ha Nam Province agreed well with the descriptions of Bain et al. (2009) and Hecht et al. (2013): SVL 27.5 mm in male (n = 1); head longer than wide (HW 9.0 mm, HL 9.5 mm); snout subacuminate in dorsal view, longer than eye (RL 5.0 mm, ED 4.8 mm); interorbital distance 1.7 times broader than upper eyelid (UEW 2.5 mm, IOD 4.3 mm); tympanum distinct, round (TD 1.5 mm); vomerine teeth absent; tongue notched posteriorly; vocal sacs absent. Fore-limb slender (FL 14.5 mm); fingers free of webbing, tips of fingers expanded into large discs, relative finger lengths I < II < IV <III; nuptial pad present in male. Hind-limb slender, tibia longer than thigh (TbL 15.8 mm; TbL 14.5 mm); toe tips expanded into discs; webbing present, webbing formula: I1–1 1/2II1–2III1 3/4–3IV3–1 3/4V; inner metatarsal tubercle elongate; outer metatarsal tubercle absent; tibio-tarsal articulation reaching tip of snout. Dorsal skin granular, with keratinised spicules on small, isolated bumps; dermal fringes on the postaxial portions of the limbs absent; throat smooth, becoming coarsely tubercular towards the belly. Colouration in life: Dorsum rusty brown with three black spots on mid-dorsal, near eyelid on each side and near shoulder; lip and upper portion of limbs with small white spots; upper part of flanks with black blotches; throat, chest and belly grey-brown with cream spots (Fig. 17).

Figure 17.  

Theloderma lateriticum (adult male, IB A.5407).

In Vietnam, this species is known from Lao Cai, Son La, Ha Giang, Bac Giang, Quang Ninh and Ha Tinh Provinces (Hecht et al. 2013, Pham and Nguyen 2018, Frost 2025). Elsewhere, this species is known from China and Laos (Frost 2025).

Specimen of Theloderma lateriticum was found on a tree branch near a small stream at 20:30 h. Tadpoles were observed inhabiting water-filled bamboo tubes. The surrounding habitat was a mixed secondary forest of small hardwood and shrubs.

Conservation status. LC (Least Concern) (IUCN 2025).