Oreolalax sterlingae Nguyen, Phung, Le, Ziegler & Böhme, 2013
Sterling's Toothed Toad
|Species Description: Nguyen TQ., Phung TM, Le MD, Ziegler T, Böhme W 2013. First record of the genus Oreolalax (Anura: Megophryidae) from Vietnam with descirption of a new species. Copeia 2013: 213–222.|
© 2019 Daniel Kane (1 of 11)
Oreolalax sterlingae is a relatively small Megophryide frog described from one male and one female specimen that have snout-vent lengths of 37 mm and 45 mm, respectively. The head has a protruding snout, distinct canthus rostralis, and concave loreal region. The nostrils are located between the tip of the snout and the eye. The pupil is vertical. Behind the eye, the tympanum is hidden, but the parotoid gland is obvious and elongated. The forelimbs are uniquely enlarged and comparatively shorter. The fingers have round tips, and lack dermal fringes and webbings. The male has nuptial spines on fingers I and II. The tibia is shorter than the femur, and the foot is long with thin, long, and round-tipped toes. Webbing is only present at the base of the toes. The subarticular tubercles are distinct in O. sterlingae. It does not have outer metatarsal tubercle or tarsal folds, but does have an undeveloped inner metatarsal tubercle. There are round spiny warts on the dorsum, and, in males, a smaller patch of spines on chest (Nguyen et al. 2013).
The tadpoles have ovoid bodies, a rounded snout, a left-directing spiracle, and dorsally positioned eyes (Rowley et al. 2017).
Oreolalax sterlingae is smaller relative to all other species in genus Oreolalax, and only has webbing at the base of the toes compared to the fully webbed O. granulosus and O. weigoldi, and nearly fully webbed O. xiangchengensis. The tympanum is hidden in O. sterlingae, but obvious in O. rhodostigmatus. Oreolalax sterlingae has uniquely round spiny warts on the dorsum, and smaller spinal patches on chest that distinguish it from O. granulosus, O. jingdongensis, O. liangbeiensis, O. major, O. multipunctatus, O. nanjiangensis, and O. popei. There is dark marbling on O. sterlingae’s belly and limbs, while O. liangbeiensis, O. nanjiangensis, O. pingii, O. puxiongensis, and O. schmidti lack markings. Moreover, O. sterlingae’s belly is smooth rather than grainly as in O. weigoldi. White spots appear on the flanks of O. sterlingae, but are not present in O. chuanbeiensis, O. granulosus, O. major, O. multipunctatus, O. nanjiangensis, O. omeimontis, and O. popei. There is no dark triangular pattern on the interorbital region of O. sterlingae, but one is present in O. omeimontis, O. puxiongensis, and O. schmidti. Three dark bars are present on the upper thigh of O. sterlingae, but absent in O. pingii (Nguyen et al. 2013).
The tadpole of O. sterlingae is smaller than all the related species in the genus Oreolalax, but it resembles O. granulosus in black coloration (Rowley et al. 2017).
Live O. sterlingae have a brown dorsum with small black spines and cream venter with brown mottling. Whitish spots are present on the lip and limbs, and yellowish-white spots are present on the lower flanks. In preservative, O. sterlingae’s brown fades into grayish brown, but otherwise, colors do not change much (Nguyen et al. 2013).
The tadpoles have black bodies and pale tail fins that are clear with a gold stripe running anteriorly on both the upper and lower margins (Rowley et al. 2017).
There is some sexual dimorphism in this species. The male has black spines on the lower lip, small spinal patches on the chest, and nuptial spines on fingers I and II, while the female has less prominent warts (Nguyen et al. 2013).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Viet Nam
Life History, Abundance, Activity, and Special Behaviors
Type specimens of O. sterlingae were collected at night, but it is unclear if this species is nocturnal or diurnal (Nguyen et al. 2013).
Oreolalax sterlingae is noted as being locally abundant, but the population is expected to be small and decreasing due to its small Extent of Occurrence and increasing threats (IUCN 2015).
Adult O. sterlingae live near rocky streams and rivulets in bamboo forests, where they experience heavy precipitation in a temperature range of -3 to 20 degrees celsius (Nguyen et al. 2013; IUCN 2015).
Oreolalax sterlingae is assumed to be ovoviviparous and have indirect development like other members of the genus Oreolalax (IUCN 2015).
Oreolalax sterlingae has no vocal sac, and no call has been recorded (Nguyen et al. 2013).
A female (paratype) was documented with yellow eggs (3.6 mm in diameter) in the body (Nguyen et al. 2013).
Tadpoles are aquatic and can be observed year-round in large pools of rocky streams (Tapley et al. 2020). They are bottom dwellers that prefer actively flowing water (Rowley et al. 2017).
Trends and Threats
Relation to Humans
Possible reasons for amphibian decline
General habitat alteration and loss
Both Maximum Parsimony and Bayesian Inference analyses of mitochondrial genes 12S and 16S show that O. sterlingae is a unique member of the genus Oreolalax. More specifically, O. sterlingae is sister to the clade containing O. chuanbeiensis, O. multipunctatus, O. nanjiangensis, O. omeimontis, and O. popei (Nguyen et al. 2013). However, this placement is not strongly supported by either analysis. More information from both mitochondrial and nuclear genes is needed to provide a more solid placement (Nguyen et al. 2013).
The specific epithet “sterlingae” refers to Dr. Eleanor J. Sterling from the American Museum of Natural History in New York, in recognition of her exceptional contribution to biodiversity research and conservation in Vietnam, where the species is found (Nguyen et al. 2013).
OTHER INTERESTING INFORMATION:
Oreolalax sterlingae was the first species from the genus Oreolalax that was described outside of China (Nguyen et al. 2013).
Foster, P. (2001). “The potential negative impacts of global climate change on tropical montane cloud forests.” Earth-Science Reviews, 55 (1-2), 73-106. [link]
IUCN SSC Amphibian Specialist Group. (2015). "Oreolalax sterlingae." The IUCN Red List of Threatened Species 2015: e.T76491633A76491638. https://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T76491633A76491638.en. Downloaded on 16 February 2021.
Nguyen, T. Q., Phung, T. M., Le, M. D., Ziegler, T., Böhme, W. (2013). “First record of the genus Oreolalax (Anura: Megophryidae) from Vietnam with description of a new species.” Copeia, 2(2), 213-222. [link]
Rowley, J. J. L., Tapley, B., Chung, N. T., Altig, R. (2017). “Tadpole of the critically endangered Sterling’s toothed toad (Oreolalax sterlingae).” Zootaxa, 4272(4), 579-582. [link]
Tapley, B., Nguyen, L. T., Portway, C., Cutajar, T., Nguyen, C. T., Luong, H. V., Kane, D., Harding, L., Rowley, J. J. L. (2020). “A point endemic no more; a range extension for Oreolalax sterlingae (Nguyen et al., 2013) in Bat Xat District, Lao Cai Province, northern Vietnam.” Herpetology Notes, 13, 497-500. [link]
Originally submitted by: Feipeng Huang, Duoduo Nie, Qiao Wei (2022-02-02)
Description by: Feipeng Huang, Duoduo Nie, Qiao Wei (updated 2022-02-02)
Distribution by: Feipeng Huang, Duoduo Nie, Qiao Wei (updated 2022-02-02)
Life history by: Feipeng Huang, Duoduo Nie, Qiao Wei (updated 2022-02-02)
Trends and threats by: Feipeng Huang, Duoduo Nie, Qiao Wei (updated 2022-02-02)
Relation to humans by: Feipeng Huang, Duoduo Nie, Qiao Wei (updated 2022-02-02)
Comments by: Feipeng Huang, Duoduo Nie, Qiao Wei (updated 2022-02-02)
Edited by: Ann T. Chang (2022-02-02)
Species Account Citation: AmphibiaWeb 2022 Oreolalax sterlingae: Sterling's Toothed Toad <https://amphibiaweb.org/species/8524> University of California, Berkeley, CA, USA. Accessed Apr 1, 2023.
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Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 1 Apr 2023.
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