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

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. wuhuangmon