Leptobrachella huynhi Hoang, Luong, Nguyen, Nguyen, Ninh, Le, Ziegler & Pham, 2024

Hoang, Chung Van, Luong, Anh Mai, Nguyen, Truong Quang, Nguyen, Tao Thien, Ninh, Hoa Thi, Le, Linh Hoang Tu, Ziegler, Thomas & Pham, Cuong The, 2024, A new species of Leptobrachella Smith 1925 (Anura, Megophryidae) from Lai Chau Province, Vietnam, Biodiversity Data Journal 12, pp. e 136491-e 136491 : e136491-

Leptobrachella huynhi Hoang, Luong, Nguyen, Nguyen, Ninh, Le, Ziegler & Pham sp. nov.

Materials

Type status: Holotype. Occurrence: catalogNumber: IEBR A.5213 ; individualCount: 1; sex: female; lifeStage: adult; occurrenceID: ADA40C4B-F74B-57C6-9C9F-EBEEB882CF34; Taxon: scientificNameID: Leptobrachella huynhi ; scientificName: Leptobrachella huynhi ; class: Amphibia; order: Anura ; family: Megophryidae ; genus: Leptobrachella ; specificEpithet: huynhi ; Location: country: Vietnam; countryCode: VN; stateProvince: Lai Chau; locality: Sin Ho District ; verbatimElevation: 1630 m; verbatimLatitude: 22°20'15.4"N; verbatimLongitude: 103°14'32.6"E; verbatimCoordinateSystem: WGS 84; Event: eventDate: July 13, 2016; eventRemarks: collected by T. T. Nguyen, H. T. Ninh, and C. V. Hoang; Record Level: collectionCode: Amphibia; basisOfRecord: PreservedSpecimen

Type status: Paratype. Occurrence: catalogNumber: IEBR A.5214 ; individualCount: 1; sex: female; lifeStage: adult; occurrenceID: 0C7AD5AD-FC31-538D-B0AC-8D2A6E35637D; Taxon: scientificNameID: Leptobrachella huynhi ; scientificName: Leptobrachella huynhi ; class: Amphibia; order: Anura ; family: Megophryidae ; genus: Leptobrachella ; specificEpithet: huynhi ; Location: country: Vietnam; countryCode: VN; stateProvince: Lai Chau; locality: Sin Ho District ; verbatimElevation: 1630 m; verbatimLatitude: 22°20'15.4"N; verbatimLongitude: 103°14'32.6"E; verbatimCoordinateSystem: WGS 84; Event: eventDate: July 13, 2016; eventRemarks: collected by T. T. Nguyen, H. T. Ninh, and C. V. Hoang; Record Level: collectionCode: Amphibia; basisOfRecord: PreservedSpecimen

Type status: Paratype. Occurrence: catalogNumber: IEBR A.5215 ; individualCount: 1; sex: female; lifeStage: adult; occurrenceID: CCA446DE-880F-563F-B041-75B83DF3DC56; Taxon: scientificNameID: Leptobrachella huynhi ; scientificName: Leptobrachella huynhi ; class: Amphibia; order: Anura ; family: Megophryidae ; genus: Leptobrachella ; specificEpithet: huynhi ; Location: country: Vietnam; countryCode: VN; stateProvince: Lai Chau; locality: Sin Ho District ; verbatimElevation: 1630 m; verbatimLatitude: 22°20'15.4"N; verbatimLongitude: 103°14'32.6"E; verbatimCoordinateSystem: WGS 84; Event: eventDate: July 13, 2016; eventRemarks: collected by T. T. Nguyen, H. T. Ninh, and C. V. Hoang; Record Level: collectionCode: Amphibia; basisOfRecord: PreservedSpecimen

Type status: Paratype. Occurrence: catalogNumber: IEBR A.5216 ; individualCount: 1; sex: female; lifeStage: adult; occurrenceID: E3AA48BF-E1CF-5EA0-853D-8A8090B9706C; Taxon: scientificNameID: Leptobrachella huynhi ; scientificName: Leptobrachella huynhi ; class: Amphibia; order: Anura ; family: Megophryidae ; genus: Leptobrachella ; specificEpithet: huynhi ; Location: country: Vietnam; countryCode: VN; stateProvince: Lai Chau; locality: Sin Ho District ; verbatimElevation: 1630 m; verbatimLatitude: 22°20'15.4"N; verbatimLongitude: 103°14'32.6"E; verbatimCoordinateSystem: WGS 84; Event: eventDate: June 10, 2024; eventRemarks: collected by C. V. Hoang, C. T. Pham, T. Q. Phan, and Q. H. Do; Record Level: collectionCode: Amphibia; basisOfRecord: PreservedSpecimen

Description

Description of holotype: Habitus stocky, size medium (SVL 37.8 mm), head longer than wide (HL / HW 1.04); snout slightly projecting beyond margin of lower jaw, obtusely pointed in dorsal view; nostril round, located closer to snout tip than to eye (NS / EN 0.73); canthus rostralis distinct; loreal region sloping; eye diameter shorter than snout length (ED / SNT 0.96); pupil vertical; tympanum distinct, round, tympanum diameter smaller than eye diameter (TD / ED 0.53); slightly concave, tympanic rim not elevated to skin of temporal region; pineal ocellus absent; vomerine teeth absent; tongue large, broad, slightly concave at tip; supratympanic ridge slightly rough with few small nodules; supratympanic fold forming a distinct ridge, running from posterior corner of eye towards supra-axillary gland (Fig. 2 ).

Fore-limbs slender; finger tips round, slightly broader than phalange width; finger webbing absent, lateral fringes narrow; relative finger lengths: II <I < IV < III; nuptial pad absent; subarticular tubercles absent, replaced by distinct dermal ridges; a large, round inner palmar tubercle, distinctly separated from small, laterally compressed outer palmar tubercle (Fig. 3 ).

Hind-limbs slender, tibia length approximately half of snout-vent length (TIB / SVL 0.49). Tips of toes round, broader than phalange width; relative toe lengths: I < II < V < III < IV; interdigital toe webbing absent; toes with narrow lateral fringes; subarticular tubercles absent, replaced by distinct dermal ridges; inner metatarsal tubercle small, oval, pronounced, outer metatarsal tubercle absent (Fig. 3 ).

Skin texture in life. Skin on entire dorsum shagreened with low, round tubercles of irregular sizes, alternately arranged and scattered, tubercles becoming smaller towards venter; ventral skin smooth; pectoral gland oval, 1.6 mm in diameter; supra-axillary gland raised, oval, 0.6 mm in diameter; femoral glands round, smaller than pectoral gland (~ 0.8 mm in diameter), located on posteroventral surfaces of thighs, closer to knee than to vent; ventrolateral glands present, dorsolaterally compressed, forming an incomplete line (Fig. 2 ).

Colour in life. Dorsum grey-brown with indistinct dark brown markings, flank and heel light-brown with some dark flecks; inter-orbital region with a stacking double Y-shaped marking, anterior part stretched to two upper lips, posterior part stretched towards the area between axillae; marbling between axillae and inguinal region; tympanum with brown colour that blends well with the surrounding region, a dark brown stripe below supratympanic ridge, running from posterior corner of eye towards supra-axillary gland; supra-axillary region light-brown; dorsal surface of limbs, fingers and toes with diffuse, transverse dark brown bars, interwoven by brown bars; centre of belly creamy-white, outer edges of belly brown with small whitish spots; ventral surface of the chin, thighs, arms and tibiotarsus brown with small whitish spots; femoral, pectoral and dorsolateral glands creamy-white; iris copper (Fig. 2 ).

Colour in preservative. Dorsal surface grey; markings dark-grey, edged in white-grey; dorsal surface of limbs, fingers and toes with diffuse, transverse dark-grey bars, interwoven by beige bars; centre of belly, throat and chest cream; chin, thighs, arms, tibiotarsus and outer edges of belly, throat and chest beige with small cream spots; cream pectoral glands became indistinct in preservative (Fig. 3 ).

Diagnosis

Leptobrachella huynhi sp. nov. is distinguished from its congeners by a combination of the following morphological characteristics: Size medium (SVL 37.8–40.2 mm, n = 4 adult females); head longer than wide; tympanum distinct; skin on entire dorsum shagreened; toes without interdigital webbing and with narrow lateral fringes; supratympanic ridge slightly rough with few nodules; dorsum grey-brown with indistinct dark brown markings; interorbital region with a stacking double Y-shaped marking; centre of belly creamy-white, outer edges of belly brown with small whitish spots; iris copper. In addition, the new species is genetically distinct from other species in the genus with uncorrected genetic distances ≥ 3.62 % (mitochondrial gene 16 S rRNA).

Etymology

The new species is named after Prof. Dr. Huynh Huy Dang, Chairman of the Zoological Society of Vietnam, to honour his great contributions to the vertebrate fauna of Vietnam. We recommend “ Huynh’s Leaf-litter Frog ” as the common English name and “ Cóc mày hu ỳnh ” as the Vietnamese name.

Distribution

Leptobrachella huynhi sp. nov. is currently known from Sin Ho District, Lai Chau Province, Vietnam (Fig. 1 ).

Ecology

Specimens of the new species were found in small streams at elevations ~ 1630 m a. s. l. in evergreen forest nearby Sin Ho Town and intercity road DT 128 (Fig. 4 ). Leptobrachella huynhi sp. nov. occurs sympatrically with L. ventripunctata .

Notes

Variation

Type specimens vary in body size and colour pattern in life (Table 1 , Figs 2 , 3 ). Glands around cloacal opening vary in size and number. In preservative, dorsal skin texture varies from finely tuberculate to almost smooth.

Comparisons

Comparative morphological data of Leptobrachella huynhi sp. nov. and 79 recognised Leptobrachella species occurring north of the Isthmus of Kra are listed in Suppl. material 2.

In the phylogenetic tree (Fig. 5 ), Leptobrachella huynhi sp. nov. is a sister taxon to L. shiwandashanensis , L. wuhuangmontis , L. shangsiensis , L. pluvialis , L. minima , L. ventripunctata , L. aerea , L. feii , L. aspera , L. damingshanensis , L. nahangensis , L. nyx and L. phiadenensis with a high support value (0.94 in BI, 85 in ML) and the new species can be distinguished from them by genetic divergences of at least 3.62 % (Suppl. material 3).

Morphologically, the new species differs from L. shiwandashanensis by having a larger body size in females (SVL 37.8–40.2 mm vs. 32.3–35.9 mm in L. shiwandashanensis ), toes with narrow lateral fringes (vs. absent in L. shiwandashanensis ), head longer than wide (HL / HW 1.05 vs. 0.95 in L. shiwandashanensis ), a greater ratio of HL / SVL (0.39 vs. 0.32 in L. shiwandashanensis ), a greater ratio of TIB / SVL (0.49 vs. 0.43 in L. shiwandashanensis ), tympanum diameter larger than half of eye diameter (TD / ED 0.61 vs. 0.49 in L. shiwandashanensis ) and iris copper (vs. iris bicoloured: upper half brownish-red and silver in the lower half in L. shiwandashanensis ) ( Chen et al. 2021, Lo et al. 2022); from L. wuhuangmontis by having a larger body size in females (SVL 37.8–40.2 mm vs. 33.0–36.0 mm in L. wuhuangmontis ), dorsal skin shagreened with low, round tubercles (vs. rough, scattered with dense conical tubercles in L. wuhuangmontis ), centre of belly creamy-white, outer edges of belly brown with small whitish spots (vs. belly greyish-white mixed by tiny white and black dots in L. wuhuangmontis ), a greater ratio of HL / SVL (0.39 vs. 0.36 in L. wuhuangmontis ), a greater ratio of TIB / SVL (0.49 vs. 0.45 in L. wuhuangmontis ) and iris copper (vs. iris bicoloured: coppery yellow on upper half and silver on lower half in L. wuhuangmontis ) ( Wang et al. 2018); from L. shangsiensis by having a larger body size in females (SVL 37.8–40.2 mm vs. 30.8–35.9 mm in L. shangsiensis ), dorsal skin with low, round tubercles (vs. mostly smooth with numerous tiny tubercles in L. shangsiensis ), centre of belly creamy-white, outer edges of belly brown with small whitish spots (vs. yellowish-creamy-white in L. shangsiensis ), head longer than wide (HL / HW 1.05 vs. 0.92 in L. shangsiensis ), a greater ratio of HL / SVL (0.39 vs. 0.31 in L. shangsiensis ), a greater ratio of TIB / SVL (0.49 vs. 0.47 in L. shangsiensis ), tympanum diameter larger than half of eye diameter (TD / ED 0.61 vs. 0.50 in L. shangsiensis ) and iris copper (vs. iris copper in the upper and silver in the lower fifth in L. shangsiensis ) ( Chen et al. 2019); from L. pluvialis by having a larger body size in females (SVL 37.8–40.2 mm vs. 25.5–33.5 mm in L. pluvialis ), dorsal skin shagreened with low, round tubercles (vs. smooth, flattened dorsal tubercles on dorsal in L. pluvialis ), toes with narrow lateral fringes (vs. without lateral fringes in L. pluvialis ), centre of belly creamy-white, outer edges of belly brown with small whitish spots (vs. dirty white with dark brown marbling in L. pluvialis ), a greater ratio of NS / EN (0.81 vs. 0.78 in L. pluvialis ) and iris copper (vs. dark golden in L. pluvialis ) ( Ohler et al. 2000, Nguyen et al. 2021); from L. minima by having a larger body size in females (SVL 37.8–40.2 mm vs. 31.6–37.3 mm in L. minima ), skin on entire dorsum shagreened with low, round tubercles (vs. smooth in L. minima ), toes with narrow lateral fringes (vs. without lateral fringes in L. minima ), centre of belly creamy-white, outer edges of belly brown with small whitish spots (vs. creamy-white in L. minima ), toe webbing absent (vs. toe webbing rudimentary in L. L. minima ) and iris copper (vs. iris dark gold above and grey below in L. minima ) ( Taylor 1962, Ohler et al. 2011); from L. ventripunctata by having a larger body size in females (SVL 37.8–40.2 mm vs. 31.5–35.0 mm L. ventripunctata ), skin on entire dorsum shagreened with low, round tubercles (vs. longitudinal skin ridges in L. ventripunctata ), toes with narrow lateral fringes (vs. without lateral fringes in L. ventripunctata ), toes webbing absent (vs. rudimentary toes webbing in L. ventripunctata ), centre of belly creamy-white, outer edges of belly brown with small whitish spots (vs. chest and belly with dark brown spots in L. ventripunctata ) and iris copper (vs. bicoloured iris: copper above and grey-brown below in L. ventripunctata ) ( Fei et al. 1991, Fei et al. 2009, Fei et al. 2012); from L. aerea by having toes with narrow lateral fringes (vs. well developed in L. aerea ), variable dorsolateral markings (vs. indistinct dorsolateral markings in L. aerea ), toes with narrow lateral fringes (vs. well developed in L. aerea ), a greater ratio of HL / SVL (0.39 vs. 0.37 in L. aerea ) and a smaller ratio of ED / SNT (0.88 vs. 0.91 in L. aerea ) ( Rowley et al. 2010); from L. feii by having a larger body size in females (SVL 37.8–40.2 mm vs. 25.7 mm in L. feii ), centre of belly creamy-white, outer edges of belly brown with small whitish spots (vs. creamy-white with black blotches in L. feii ), ventrolateral glands forming a discontinuous line (vs. ventrolateral glands forming a continuous line in L. feii ), a smaller ratio of ED / SNT (0.88 vs. 0.92 in L. feii ), a greater ratio of TIB / SVL (0.49 vs. 0.46 in L. feii ) and iris copper (vs. iris bicoloured: golden orange in upper half and silver white in lower half in L. feii ) ( Chen et al. 2020); from L. aspera by having a larger body size in females (SVL 37.8–40.2 mm vs. 25.0– 26.4 mm in L. aspera ), skin on entire dorsum shagreened with low, round tubercles (vs. rough with dense conical granules, tubercles and dermal ridges in L. aspera ), centre of belly creamy-white, outer edges of belly brown with small whitish spots (vs. creamy-white with distinct dark spots and distinct regular dark patches on skin of chest and abdomen in L. aspera ), a greater ratio of HL / SVL (0.39 vs. 0.33–0.35 in L. aspera ), relative finger lengths II <I < IV < III (vs. I < IV < II < III in L. aspera ) and iris copper (vs. iris bicoloured: amber on upper half and silver on lower half in L. aspera ) ( Wang et al. 2020); from L. damingshanensis by having skin on entire dorsum shagreened with low, round tubercles (vs. rough with small, raised tubercles and ridges in L. damingshanensis ), variable dorsolateral markings (vs. indistinct dorsolateral markings in L. damingshanensis ), a greater ratio of HL / HW (1.05 vs. 0.89 in L. damingshanensis ), a greater ratio of HL / SVL (0.39 vs. 0.31 in L. damingshanensis ), a smaller ratio of ED / SNT (0.88 vs. 0.92 in L. damingshanensis ) and iris copper (vs. iris bicoloured upper half copper, fading to silver in lower half in L. damingshanensis ) ( Chen et al. 2021 b); from L. nahangensis by having skin on entire dorsum shagreened with low, round tubercles (vs. smooth in L. nahangensis ), centre of belly creamy-white, outer edges of belly brown with small whitish spots (vs. creamy-white with light speckling on throat and chest in L. nahangensis ) and iris copper (vs. iris gold, uniformly distributed with minute black reticulations in L. nahangensis ) ( Lathrop et al. 1998); from L. nyx by having ventrolateral glands forming a discontinuous line (vs. lateroventral glandular ridge poorly distinct in L. nyx ), toes with narrow lateral fringes (vs. absent lateral fringes in L. nyx ), a greater ratio of HL / SVL (0.39 vs. 0.38 in L. nyx ), a greater ratio of TIB / SVL (0.49 vs. 0.48 in L. nyx ) and skin on entire dorsum shagreened with low, round tubercles of irregular sizes, alternately arranged and scattered, tubercles becoming smaller towards ventral (vs. dorsal and lateral parts of head and body: snout and side of head smooth; region between eyes, back and flanks with flat glandular warts, quite indistinct on dorsal part in L. nyx ) ( Ohler et al. 2011); and from L. phiadenensis by having a larger body size in females (SVL 37.8–40.2 mm vs. 27.6–28.6 mm in L. phiadenensis ), a greater ratio of (HL / HW 1.05 vs. 0.94–0.97 in L. phiadenensis ), a greater ratio of HL / SVL (0.39 vs. 0.35 in L. phiadenensis ) and iris copper (vs. iris bicoloured: copper in upper half, fading to silvery grey in its lower half in L. phiadenensis ) ( Luong et al. 2023).

Figures

Figure 1. Map showing the type locality (red circle) of Leptobrachella huynhi sp. nov. in Lai Chau Province, northern Vietnam. Black star: Hanoi Capital.

Figure 2. Holotype of Leptobrachella huynhi sp. nov. (IEBR A. 5213, female) in life.

Figure 3. Holotype of Leptobrachella huynhi sp. nov. (IEBR A. 5213), A dorsal view; B ventral view; C left hand; D right foot; E right side of head; F cloacal region in preservative.

Figure 4. Habitat of Leptobrachella huynhi sp. nov. in Sin Ho District, Lai Chau Province, Vietnam.

Figure 5. The Bayesian Inference (BI) tree, based on the partial 16 S rRNA mitochondrial gene. Values at nodes correspond to BI / ML support values, respectively. Leptobrachium cf. chapaense and Megophrys truongsonensis are used in the outgroup.