Yunkai Mountain’s Leaf Litter Toad; Yun Kai Zhang Tu Chan (云开掌突蟾)
Species Description: Wang J, Yang J, Li Y, Lyu Z, Zeng Z, Liu Z, Ye Y, and Wang Y. 2018. Morphology and molecular genetics reveal two new Leptobrachella species in southern China (Anura, Megophryidae). ZooKeys 776: 105-137.
Leptobrachella yunkaiensis is a small frog with snout-vent lengths for males ranging from 25.9 – 29.3 mm, and for females ranging from 34.0 – 35.3 mm. Leptobrachella yunkaiensis have rough, shagreened dorsal skins with short ridges and warts. Head lengths are slightly greater than head widths. The snout protrudes slightly and projects slightly beyond the margin of the lower jaw. The snout length is slightly larger than the eye diameter. The nostrils are equidistant from the eyes and the snout. There is a large distance between nostrils. The canthus rostralis is smoothly rounded. The loreal region is concaves to a small extent. The interorbital space is flat. The pineal ocellus is absent, and the pupils are vertical. The tympanum's diameter is less than that of the eyes but greater than the distance between the eye and the tympanum. The tympanums are concave and are visually distinguishable with a thin supratympanic line. The supra-axillary, femoral, pectoral and ventrolateral glands are clearly visible (Wang et al. 2018).
The fingertips are rounded. The third finger is the longest while the rest are about equal length. The relative finger lengths are I = II = IV < III. Nuptial pads and subarticular tubercles are absent. There is a large rounded inner palmer tubercle and a small, round outer palmar tubercle. The hand has no webbing but does have distinguishable lateral fringes on fingers. The tips of the toes are similar to the tips of the fingers. When the hindlimbs are held at right angles to the body, the heels just touch. When the leg is held along the body, the tibiotarsal articulation reaches the eye. Relative toe lengths are I < II < V < III < IV. There are no subarticular tubercles. Dermal ridges are present under the 3rd and the 5th toes. There is a large, oval, inner metatarsal tubercle, but no outer metatarsal tubercle. The toes have rudimentary webbing and wide lateral fringes. The longitudinal ridges on the toes are not interrupted by articulations. Dense conical spines are present on lateral and ventral sides of tarsus, surfaces of tibia-tarsal, inner surface of the shank and around the cloacal region (Wang et al. 2018).
Leptobrachella yunkaiensis can be easily distinguished from the 24 known species of Leptobrachella south of the Isthmus of Kra, including L. arayai, L. dringi, L. fritinniens, L. gracilis, L. hamidi, L. heteropus, L. kajangensis, L. kecil, L. marmorata, L. melanoleuca, L. maura, L. picta, L. platycephala, L. sabahmontana and L. sola, by the focal species having supra-axillary and ventrolateral glands. Significantly larger body sizes for both males and females also differentiates L. yunkaiensis from smaller species including L. brevicrus, L. itiokai, L. juliandringi, L. mjobergi, L. natunae, L. parva, L. palmata, L. serasanae (Wang et al. 2018).
Some other species of Leptobrachella are distinguishably larger than L. yunkaiensis, including L. eos, L. nahangensis, L. pyrrhops, L.sungi, L.zhangyapingi. Some species are smaller than L. yunkaiensis, including L. applebyi, L. melica, L. pluvialis. Leptobrachella yunkaiensis have wide fringes on toes that differ from L. applebyi, L. ardens, L. crocea, L. kalonensis, L. lateralis, L. maculosa, L. macrops, L. melica, L. minima, L. nahangensis, L. nyx, L. oshanensis, L. pallida, L. pluvialis, L. pyrrhops, L. rowleyae, L. tadungensis, L. tuberosa, and L. ventripunctata, all of which have no lateral fringes on their toes at all. Leptobrachella bidoupensis, L. bourreti, L. fuliginosa, and L. sungi have weak lateral fringes on toes. Leptobrachella botsfordi, L. maoershanensis, L. pelodytoides, L. petrops, L. puhoatensis, and L. tengchongensis only have narrow lateral fringes on toes. Leptobrachella alpinus, L. firthi, and L. isos have wide lateral fringes, but in males only. Leptobrachella yunkaiensis has rudimentary webbing on toes that are not present in L. ardens, L. kalonensis, L. maculosa, L. oshanensis, L. pallida, L. petrops, L. rowleyae, and L. tadungensis. Leptobrachella pelodytoides, L. sungi, and L. tamdi have wide toe webbings whereas L. yunkaiensis has only rudimentary webbing. Leptobrachella yunkaiensis have black spots on flanks that are not present in L. aerea, L. botsfordi, L. eos, L. firthi, L. isos, L. pallida, L. petrops, L. tuberosa, and L. zhangyapingi. Leptobrachella bourreti, L. eos, L. firthi, L. khasiorum, L. lateralis, L. minima, L. nahangensis, and L. nokrekensis all have a uniform creamy white belly in contrast to the pinkish belly of L. yunkaiensis. Leptobrachella macrops has a greyish-violet belly with white speckling. Leptobrachella purpura has a dull-white belly with dark brown flecks on the chest and margins. Leptobrachella yingjinagensis have creamy white chests and margins of the belly with dark brown flecks. Leptobrachella purpura, L. yingjiangensis, and L. tengchongensis have shagreened dorsal skin with small tubercles in contrast to the raised warts in L. yunkaiensis. Leptobrachella macrops has no skin ridges on the dorsal surface (Wang et al. 2018).
Leptobrachella yunkaiensis is the most similar to L. laui and L. liui. However, female L. yunkaiensis are still much larger in size compared to these two. Female L. yunkaiensis have snout-vent lengths between 34.0 - 35.3 mm, whereas a female sample of L. laui has a snout-vent length of 28.1 mm. Sample females of L. liui have snout-vent lengths from 23.0 – 28.0 mm. Other than sizes, both L. laui and L. liui share similar traits with L. yunkaiensis. Leptobrachella laui and L. yunkaiensis both have weak black supratympanic lines and uninterrupted longitudinal ridges under toes. However, L. laui does not have short skin ridges and raised warts on dorsum and has a creamy white belly with brown dustings instead of pinkish belly like L. yunkaiensis. Leptobrachella liui have short skin ridges and raised warts on the dorsum similar to the ones in L. yunkaiensis, however, L. liui has distinct supratympanic lines and interrupted under-toe ridges at articulations. Leptobrachella liui also has a creamy white belly with dark-brown spots on the chest and margin (Wang et al. 2018).
Leptobrachella wuhuangmontis differs from L. yunkaiensis by the narrowness of lateral fringes on toes, distinct supratympanic lines, scattered dense conical tubercles on the dorsal surface of the body, and a greyish white belly (Wang et al. 2018).
In life, L. yunkaiensis have orange-brown dorsal surfaces with dark brown blotches of light orange on the edge. The lateral surfaces also have several dark blotches. Between the eyes, there is a dark brown triangular pattern. There is a W-shaped marking between axillae. The tympanum is black, and is visually distinguishable with a thin, light black supratympanic line. Orange-brown tubercles are present on the dorsum of the body and limb. Tubercles on flanks are also orange-brown but are much denser and more distinct than those on the dorsum. There are apparent blackish brown patches on the upper lip. On the dorsal surface of the limbs, there are transverse dark-brown bars. There are indistinct dark brown blotches on flanks from the groin to the axilla. The upper arms, including the elbows, do not have dark stripes present, but the coloration is coppery orange. The fingers and toes have indistinct dark brown blotches. The surface of the throat is creamy white with scattered small whitish dots. The belly is pinkish with scattered small brown speckling. The ventral surface of the thighs is also pinkish, but with scattered small light orange-brown spots. The supra-axillary is coppery orange. The femoral, pectoral and ventrolateral glands are all whitish orange. The irises have two colors: the upper half is coppery orange while the lower half is silver (Wang et al. 2018).
In preservative, the orange spots fade away. The dorsum of the body and hindlimbs becomes dark brown while the dorsum of forelimbs is yellowish brown. The transverse stripes on limbs become more distinct. Dark brown patterns, markings, and spots on the back become less distinct. The ventral surfaces of the body become yellowish brown with brown marbling on the sides and the chest. The femoral, pectoral and ventrolateral glands fade to greyish white (Wang et al. 2018).
In general, the paratypes match the overall characters described in holotype except that in the holotype has a tibiotarsal articulation reaches the middle of the eye while some paratypes have it reaching the anterior or posterior corner of the eye. The distinct dark-brown speckling scattered on the surface of the belly of the holotype is indistinct in some female paratypes. The tympanum is black in the holotype but has orange speckling in some paratypes. Additionally, L. yunkaiensis exhibits sexual dimorphism. Females have larger body sizes than males do. Males have a single vocal sac, and males have distinct dense conical spines on the lateral and ventral surface of the tarsus, the surface of the tibia-tarsal regions, the inner-side surface of the shank, the surface of thighs and the surface around the cloacal region. However, the conical spines are barely visible in females (Wang et al. 2018).
Distribution and Habitat
Life History, Abundance, Activity, and Special Behaviors
Trends and Threats
Relation to Humans
Possible reasons for amphibian decline
General habitat alteration and loss
Bayesian Inference and Maximum Likelihood analysis on 476 base pairs 16S mitochondrial DNA sequences show that the clade containing L. laui, L. liui, and L. maoershanensis is most closely related to L. yunkaiensis, given a 100% and 91% probability from Bayesian inference and Maximum likelihood respectively. These four species are all local to the Dawuling Forest (Wang et al. 2018).
The species epithet, "yunkaiensis", is in reference to the locality of the species: the Yunkai Mountains Range in Dawuling Forest, Guangdong, China. The suggested common names for this species are “Yunkai Mountain’s Leaf Little Toad” in English and “Yun Kai Zhang Tu Chan” in Chinese (Wang et al. 2018).
Wang, J., Yang, J., Li, Y., Lyu, Z., Zeng, Z., Liu, Z., Ye, Y., Wang, Y. (2018). "Morphology and molecular genetics reveal two new Leptobrachella species in southern China (Anura, Megophryidae)." ZooKeys, 776, 105-137. [link]
Originally submitted by: Hanlu Chen (first posted 2018-10-31)
Edited by: Ann T. Chang (2018-11-04)
Species Account Citation: AmphibiaWeb 2018 Leptobrachella yunkaiensis: Yunkai Mountain’s Leaf Litter Toad; Yun Kai Zhang Tu Chan (云开掌突蟾) <https://amphibiaweb.org/species/8888> University of California, Berkeley, CA, USA. Accessed Oct 18, 2021.
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Citation: AmphibiaWeb. 2021. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 18 Oct 2021.
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