Leptobrachella nahangensis (Lathrop, Murphy, Orlov & Ho, 1998)
Nahang Asian Toad, Nahang Litter Toad
|Species Description: Lathrop A, Murphy, Orlov NL, and Ho CT. (1998) Two new species of Leptolalax (Anura: Megophryidae) from northern Vietnam. Amphibia-Reptilia 19: 253–267.|
DESCRIPTION:Leptobrachella nahangensis is a large toad described from one male with a snout-vent length of 40.8 mm. The broad head is almost as wide as it is long, having a snout that appears round in dorsal view and bluntly round in profile view. The nostrils are located 2.5 times closer to the snout tip than to the eye. The internarial distance is 25% of the head width, which is 15.0 mm. The loreal region is concave and oblique, while the canthus rostralis is round, but flat in lateral view. The eyes are relatively large (6.1 mm), having a diameter twice as long as that of the tympanum (3.0 mm) and 40% of the head length (15.6 mm). The interorbital distance (7.8 mm) is 1.5 times the upper eyelid length (4.7 mm), and the upper eyelid is smooth with several pustules on the posterior corner. The tympanum is distinct, having a round shape and a supratympanic fold that extends from the eye corner to a point dorsal to the shoulder. There is a gland at the end of the supratympanic fold. The hand length (13.3 mm) is 33% of the snout-vent length and there is a large thenar tubercle that is separated from the thumb by a furrow from the smaller outer metacarpal tubercle. The relative finger lengths are I < II < IV << III. Fingers II, III, and IV have distinct ridges extending ventromedially, but the ridge is less distinct on finger II. The fingers all have swollen tips. The foot length (18.6 mm) is 46% of the snout-vent length, making it nearly as long as tibia (20.1 mm), which is 49% of the snout-vent length. Webbing is present between all toes, and a sharp ridge extending ventrally is present on toes III, IV, and V. A ventromedial truncated ridge on toe II ends with a large subarticular tubercle. The inner metatarsal tubercle is elliptical and pronounced, and an outer metatarsal tubercle is not present. The skin on the dorsum is smooth, evenly distributed with small pustules and tubercles. A dorsolateral fold is absent. The flanks, belly, throat, and ventral surface of the thighs are smooth. A low and elliptical chest gland is medial to the axilla with a length less than the diameter of the tympanum (0.49 mm). The femoral gland is 50% closer to the tibia joint than to the vent. There is a pair of pustules adjacent to the vent (Lathrop et al. 1998).
DIAGNOSIS: (How this species is differentiated from similar species)
Compared to other species in Leptolalax, the male holotype of L. nahangensis has a longer snout-vent length (40.8 mm) than L. alpinus (24 - 26.4 mm), L. arayai (30 mm), L. bourreti (36.2 mm), L. dringi (24.2 - 28.5 mm in males), L. hamidi (28 - 31 mm), L. heteropus (24.2 - 28.5 mm), L. pictus (30 - 35 mm), and L. ventripunctatus (22.5 - 28 mm). Additionally, L. nahangensis has shoulder glands, unlike L. gracilis and L. sungi. Leptobrachella nahangensis can also be diagnosed by the lack of lateral fringes on the toes, unlike L. alpinus, L. bourreti, L. heteropus, L. pelodytoides, and L. sungi. The ventral coloration of L. nahangensis is different from L. bourreti, L. dringi, and L. sungi, which have immaculate venters. The coloration of L. nahangensis also differs from L. pelodytoides, which has speckling on the chin surrounding white pustules and white spots scattered on dark brown legs. Leptobrachella nahangensis instead has light mottling from the chin to the throat, with the legs being white on the ventral surface and posterior thighs being light brown with white spots (Lathrop et al. 1998).
COLORATION: (In life and/or in preservative)
In life, L. nahangensis has a brownish-lavender dorsum covered with diffuse, dark gray-black spots, while the ventrum is pinkish-white. The flanks are gray-lavender and are covered with well-defined dark gray-black spots. The limbs and digits have transverse dark bars, and the forearm and heels are yellow-orange. The eyelids are gray. The supratympanic fold is flanked with black and has black accents, while the gland at the end of the fold is white. The tympanum is completely or partially black. Two vertical bars are on the upper lip, with one under the eye and the other in the loreal region. The black canthus rostralis extends over the snout, ending with a light vertical bar at the tip of the snout. The iris is gold with a black reticulated pattern on top (Lathrop et al. 1998).
In preservative, the dorsum and sides appear dark brown-gray while the limbs are light gray to brown-gray with transverse bars. The interorbital bar and canthus appear dark brown to black. The bars on the upper lip are black, and the bar at the tip of the snout remains light in color, lighter than the dorsum. The ventral margin of the supratympanic fold is dark brown. The ventrum is cream-white with subtle mottling on the ventral surface of the forearm, tibio-tarsus, feet, and area from the lower jaw margin to the chest. The femoral gland and pustules are white (Lathrop et al. 1998).
Distribution and Habitat
Life History, Abundance, Activity, and Special Behaviors
Leptolalax pelodytoides is sympatric and has a call composed of several chirps (Lathrop et al. 1998).
PHYLOGENETIC RELATIONSHIPS:Bayesian analysis of 16S rRNA showed that L. nahangensis is sister to L. pluvialis. The analysis also showed that Leptobrachella was monophyletic and nested within the now defunct genus, Leptolalax. As a result of the analysis, it was recommended that all species within the paraphyletic Leptolalax genus be moved into the Leptobrachella genus. Thus, Leptolalax is now recognized as a junior synonym of Leptobrachella (Chen et al. 2018).
Prior to 1998, only two species of the genus were known in Vietnam: L. pelodytoides and L. bourreti. Variation in the amount of genetic material in Vietnamese megophryidae is low. Thus, the observed difference between L. nahangensis (5.46 pg) and L. pelodytoides (5.13 ± 0.05 pg) is significant (Lathrop et al. 1998).
ETYMOLOGY (Origin or explanation of scientific name):
The species epithet, “nahangensis,” is named after the government officials, officers, and people of the Na Hang Nature Reserve, which is the type locality (Lathrop et al. 1998).
Chen, J., Poyarkov, Jr., N.A., Suwannapoom, C., Lathrop, A., Wu, Y.-H., Zhou, W.-w., Yuan, Z.-y., Jin, J.-q., Chen, H.-m., Liu, H.-q., Nguyen, T.Q., Nguyen, S.N., Duong, T.V., Eto, K., Nishikawa, K., Matsui, M., Orlov, N.L., Stuart, B.L., Brown, R.M., Rowley, J.J.L., Murphy, R.W., Wang, Y-y., and Jing, C. (2018). "Large-scale phylogenetic analyses provide insights into unrecognized diversity and historical biogeography of Asian leaf-litter frogs, genus Leptolalax (Anura: Megophryidae)." Molecular Phylogenetics and Evolution, 124, 162-171. [link]
Lathrop, A., Murphy, R. W., Orlov, N., Ho, C.T. (1998). "Two new species of Leptolalax (Anura: Megophryidae) from northern Vietnam." Amphibia-Reptilia, 19(3), 253-267. [link]
Originally submitted by: Madeline Ahn (2022-11-07)
Description by: Madeline Ahn (updated 2023-02-21)
Distribution by: Madeline Ahn (updated 2023-02-21)
Life history by: Madeline Ahn (updated 2022-11-07)
Larva by: Madeline Ahn (updated 2022-11-07)
Comments by: Madeline Ahn (updated 2022-11-07)
Edited by: Ann T. Chang (2023-02-21)
Species Account Citation: AmphibiaWeb 2023 Leptobrachella nahangensis: Nahang Asian Toad <https://amphibiaweb.org/species/5478> University of California, Berkeley, CA, USA. Accessed Dec 3, 2023.
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Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 3 Dec 2023.
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