A review of torrent frogs ([i]Amolops[/i]: Ranidae) from Bhutan, the description of a new species, and reassessment of the taxonomic validity of some [i]A. viridimaculatus[/i] group species aided by archival DNA sequences of century-old type specimens

Abstract

Seven species of the Asian torrent frogs (genus Amolops) have previously been reported from the eastern Himalayan country of Bhutan. Species identifications from the region have been largely based on photographed animals with few voucher specimens available and no molecular sampling. Understanding the taxonomic status of Bhutan’s torrent frogs has also been hampered by the poorly understood distributional limits of species from surrounding regions. Herein we utilised molecular phylogenetic and morphological data for vouchered specimens from Bhutan and provide a complete literature review of all Amolops populations reported from the country. Phylogenetic relationships were estimated by combining available sequence data (from GenBank) with newly generated sequences from recently collected Bhutanese Amolops populations. We also obtained archival DNA sequences from the type specimens of Amolops formosus, A. himalayanus, and A. kaulbacki, collected between 82 and 151 years ago. Our comparative analyses revealed a large, new (to science) species of the Amolops viridimaculatus group from eastern Bhutan. Morphological examinations of related taxa revealed that A. senchalensis from India is not a synonym of A. marmoratus. Molecular phylogenetic results supplemented by morphological data unambiguously demonstrate i) that A. himalayanus is present in eastern Nepal, ii) the presence of a previously undocumented population of A. nepalicus in eastern Nepal, iii) a 200 km range extention for A. kaulbacki into Yunnan, China, iv) that A. gyirongensis should be considered a junior subjective synonym of A. formosus, and v) that A. splendissimus from Vietnam should be considered a junior subjective synonym of A. viridimaculatus. Based on our results, we expand the Amolops viridimaculatus group to include nine species, including A. formosus, A. himalayanus, A. kaulbacki, and the new species described herein. We provisionally include a further three species in the viridimaculatus group based on morphology, A. longimanus, A. nidorbellus, and A. senchalensis. Combining our data with the literature review allowed us to identify several unidentified Amolops species from recent phylogenetic studies and remove nine frog species (including Hyla, Sylvirana, and seven Amolops species) from Bhutan’s amphibian checklist. We recognise four species of Amolops in Bhutan, three of which cannot be confidently identified to the species level based on currently available data. Keywords: Anura, taxonomy, Himalayas, conservation, vouchered-specimens

A new species of cascade frog (Anura: Ranidae: Amolops) from central Yunnan, China

“…10 ). Combining findings in this study with most recent taxonomic progress [ 5 , 13 , 35 , 36 ], we consider that so far there are 20 Amolops species known from Yunnan, accounting for the highest proportion of amphibian diversity of Yunnan (ca. 9.1%; Fig.…”

“…Measurements included: snout-vent length (SVL, from tip of snout to vent); head length (HL, from tip of snout to rear of jaws); head width (HW, width of head at its widest point); snout length (SL, from tip of snout to anterior border of eye); internarial distance (IND, distance between nares); interorbital distance (IOD, minimum distance between upper eyelids); upper eyelid width (UEW, maximum width of upper eyelid); eye diameter (ED, diameter of exposed portion of eyeball); tympanum diameter (TD, the greater of tympanum vertical and horizontal diameters); forearm and hand length (FHL, from elbow to tip of third finger); thigh length (THL, from vent to knee); tibia length (TL, from knee to heel); foot length (FL, from proximal end of inner metatarsal tubercle to tip of fourth toe); length of foot and tarsus (TFL, from tibiotarsal joint to tip of fourth toe); and horizontal diameter of digital disc of third finger (F3DSC). Comparative morphological data of congeners were taken from their original descriptions or re-descriptions [ 2 , 3 , 6 – 13 , 17 – 20 , 22 – 25 , 27 – 32 , 34 , 35 , 37 – 59 ].…”

“…The A. viridimaculatus group contains 14 species based on recent taxonomic studies [11,13,57], namely A. beibengensis Jiang, Li, Zou, Yan, and Che, 2020 [33], A. chanakya Saikia, Laskar, Dinesh, Shabnam, and Sinha, 2022 [57], A. formosus (Günther, 1876) [78], A. himalayanus (Boulenger, 1888) [79], A. kaulbacki (Smith, 1940) [80], A. longimanus (Andersson, 1939) [81], A. medogensis Li and Rao, 2005 [55], A. nidorbellus Biju, Mahony, and Kamei, 2010 [40], A. pallasitatus Qi, Zhou, Lyu, Lu, and Li, 2019 [2], A. senchalensis Chanda, 1987Chanda, "1986, A. tawang Saikia, Laskar, Dinesh, Shabnam, and Sinha, 2022 [57], A. wangyali Mahony, Nidup, Streicher, Teeling, and Kamei, 2022 [13], A. wangyufani Jiang, 2020 [34], and A. viridimaculatus (Jiang, 1983) [45]. The new species can be distinguished from these species by vomerine teeth absent (vs. present), glands in compete series along dorsolateral junction present (vs. absent), and smaller body size (vs. male SVL 75.8 mm and females SVL The A. daiyunensis group contains three species, namely A. daiyunensis (Liu and Hu, 1975) [46], A. hongkongensis (Pope and Romer, 1951) [90], and A. teochew Zeng, Wang, Lyu, and Wang, 2021 [54].…”

“…The cascade frogs of genus Amolops Cope, 1865 [1] inhabit rocky streams or waterfalls, enabled by abdominal suckers in larvae and enlarged digital discs in adults [2], and are widely distributed from Nepal and northern India eastwards to China and southwards to Malaysia [3]. The species diversity in Amolops has been poorly understood owing to morphological conservation [4,5], and efforts relying on molecular data during the last decade have greatly improved our understanding of the taxonomy and species diversity of this genus, with a high number of new species having been discovered (e.g., [3,4,[6][7][8][9][10][11][12][13]). So far, as the most speciose genus within the family Ranidae, the genus Amolops contains 79 species [14], which can be allocated 10 species groups [11].…”

First national record of Microhyla hmongorum Hoang, Nguyen, Phan, Pham, Ninh, Wang, Jiang, Ziegler and Nguyen, 2022 (Anura, Microhylidae, Microhyla) in China

“…Our findings further support the need to prioritise future attention to the diversity and taxonomy of amphibians in the southwest border region. Although various studies have clarified the taxonomy and geographic ranges of some species, such as Amolops viridimaculatus ( Zhang et al 2021 , Mahony et al 2022 ), Limnonectes limborgi ( Huang et al 2022 ) and published a series of new recorded species, new recorded genera and new species have been discovered in border region in recent years (e.g. Yuan et al (2019) , Wu et al (2021) , Zhang et al (2022) ), Amphibian diversity still remains underrated while the taxonomy of several species, such as A.…”