AmphibiaChina 中国两栖类.

Description
Amolops marmoratus is a relatively small frog, with a mean snout-vent-length of 42.7 mm for males and 75.4 mm for females. The head of the frog is broad, flat, and triangular, and is longer than it is wide. The canthus rostralis is quite distinct and curves from the eye to the nostril. The snout slopes from the eye to slightly below the nostril, protruding upward past the jaw, and the snout tip is rounded when in the dorsal view. The loreal region is noticeably concave, and the nostril is much closer to the snout than the eyes. The nostril is oval and projects laterally from the canthus and the posterior edge of the nostril has a tiny tubercle. The eyes are large (around 6.3 mm), with the pupils more horizontal than vertical. The internarial distance is slightly wider than the interorbital distance. The round, hardly noticeable tympanum is much smaller than the eye, and the annulus is not discernable. Vomerine teeth are present (Dever et al. 2012).

Each finger is long and tipped with disks, all of which have circummarginal and transverse grooves. The fingers do not have fringes. The third finger is the largest, followed by the fourth, second, and then first. Moreover, males have nuptial pads on their first fingers. Subarticular tubercles can be found on the mid-ventral edge. Webbing is not found on the hands. The hindlimbs are quite long and the heels overlap when the legs are approximately at right angles to the body. The toes are fully webbed, with a webbing formula of I1 – 1MII1 – 1MIII1 – 1MIV1 – 1, and have fringes that reach the disks. These disks are smaller in size compared to the disks seen on the fingers, though both have grooves. Subarticular tubercles are present on all toes (Dever et al. 2012).

The skin of the frog is granular along the dorsal surface. Raised tubercles can be found on the sides and back of the thighs to the vent. The dorsum of the arms and legs is covered in small, flat tubercles, but a dorsolateral fold is not present. The skin is smooth on the ventral surface, and the supratympanic fold is small and hardly noticeable. Males have dual gular pouches (Dever et al. 2012).

DIAGNOSIS:

Amolops marmoratus can be potentially confused with A. afghanus as they are both morphologically similar. However, A. marmoratus are, on average, smaller than A. afghanus, especially the males. In addition to this size difference, A. marmoratus have a different coloration pattern compared to A. afghanus. The dorsum of the A. marmoratus has dark mottling and light chain patterns along with the granular dorsal skin, whereas the A. afghanus has a dark background with a lighter net-like pattern on the dorsum (Dever et al. 2012).

COLORATION:

In preserved specimens, the dorsum has dark mottling and light chain patterns, which continue to the sides of the frogs, and the ventral surface of the frog is lighter in color. The upper lip is mottled. The nuptial pads on the first fingers are white and banding on the forelimbs and hindlimbs extends to the fingers and toes. The posterior of the thighs has a light-colored blotchy pattern over a darker gray background (Dever et al. 2012). Little is recorded about the color of A. marmoratus in life.

VARIATION:

For the most part, the descriptions of the specimens analyzed matched one another, though there are some slight variations: sexual dimorphism is observed, as females are significantly larger than males, on average; the females’ heads are slightly wider than long; vomerine teeth are found in both short oblique rows and transverse rows; the outer metatarsal tubercle is indistinct; the upper lip is much darker in color (Dever et al. 2012).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Bhutan, China, India, Myanmar, Nepal, Thailand

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (9 records).

Amolops marmoratus was once believed to have a range that encompassed the Himalayas of India and Nepal, Myanmar, northern Thailand, and southern China. After the description of numerous cryptic species, arguments have been made that A. marmoratus ranges is definitively in the Mon and Shan states of Myanmar and in northwestern Thailand, and likely in the Kayin and Kayah states and the northern Tanintharyi Division of Myanmar. Chinese, Indian, and Nepalese specimens have been redefined as A. afghanus (Dever et al. 2012, Lyu et al. 2019).

Amolops marmoratus inhabits rivers, creeks, streams, and waterfalls in moist forest or wetland. These may be montane or lowland forests or wetlands. IUCN states the elevational range is between 200 - 2,000 m, though this range includes members of the cryptic species complex that are no longer believed to be A. marmoratus (van Dijk et al. 2004).

Life History, Abundance, Activity, and Special Behaviors
Amolops marmoratus lives in freshwater torrential streams, waterfalls, and surrounding bouldered areas in evergreen forests (van Dijk et al. 2004).

Amolops marmoratus reproductive modes have not been well-documented, but may be similar to A. cremnobatus, a similar species found to inhabit the same streams, who lay their eggs in jelly-like masses attached to rocks in the water (Nokhbatolfoghahai et al. 2020).

They show indirect development with aquatic tadpole larvae. Adults breed and tadpoles develop in the same torrential streams they inhabit (van Dijk et al. 2004).

Larva
Tadpole morphology is relatively unknown due to the complex cryptic range of Amolops frogs, but a 2020 study examined morphology of a suspected A. marmoratus larvae. The average total length was 41.6mm. They have a powerful tail taking up about two-thirds of the total length, with a relatively posterior dorsal fin (Nokhbatolfoghahai et al. 2020). However, this tadpole description could be for A. afghanus instead (Dever et al. 2012, Lyu et al. 2019).

Generally, tadpole members of the genus Amolops are described as having a large gastromyzophorous adhesive disk, which they use to grab onto rocks in the streams they live in (Ngo et al. 2006, Nokhbatolfoghahai et al. 2020). Suspected A. marmoratus tadpoles have specially adapted sucking jaws that allow them to both attach to rocks in fast moving water, but also to move along the substrate while remaining attached. The tadpoles are also able to stick to moist rocks above water, where they feed on wet surface biofilm. They will let go and fall back into the stream if they detect a predator nearby (Ngo et al. 2006).

Tadpoles suspected to be A. marmoratus are mottled brown and black, with a white belly (Nokhbatolfoghahai et al. 2020).

Trends and Threats
As of 2021, A. marmoratus is listed as “Least Concern” with a decreasing population trend by the IUCN. However, because of changes in the definition of the species, which are not recognized by the IUCN profile, this listing may not be accurate. There is not enough population data to form an estimated population size. Threats to A. marmoratus are believed to be agricultural deforestation, logging, agriculture and forestry pollution, and damming of rivers and streams (van Dijk et al. 2004).

Relation to Humans
Amolops species are commonly eaten by the local people of Myanmar, Thailand, and India, and is believed by some to have medicinal values such as aiding in healing broken bones, burn wounds, and joint pain (Talukdar and Sengupta 2020).

Comments

PHYLOGENETIC RELATIONSHIPS:

Using Bayesian analysis on partial DNA sequences of the mitochondrial gene (16S), it was determined that A. marmoratus’ sister taxon is the clade that contains both A. afghanus and A. indoburmanensis (Dever et al. 2012).

ETYMOLOGY:

The species epithet, “marmoratus” comes from the Latin word “marmorate”, meaning “to overlay with marble.”

SYNONYMS:

Due to the cryptic and rapidly changing taxonomy of the genus Amolops, many names have been assigned and later removed. Past taxonomic synonyms include: Ixalus argus, Polypedates afghana, Rana latopalmata, and Rana senchalensis (Frost 2013).

The current accepted common name is the Pegu torrent frog (Lyu et al. 2019). Past common name synonyms include: The marbled sucker frog (Frank and Ramus 1995), marbled cascade frog (Matthew and Sen 2010), northern cascade frog (Chan-ard 2003), Afghan frog (Li et al. 2010), Senchal frog (Chanda 2002), and the Senchal stream frog (Das and Dutta 2002).

References

Chan-ard, T. (2003). A Photographic Guide to Amphibians in Thailand. Krangkrai Swannapak, Bangkok.

Chanda, S.K. (2002). Handbook: Indian Amphibians. Zoological Survey of India, Kolkata.

Das, I. and Dutta, S.K. (1998). ''Checklist of the amphibians of India, with English common names.'' Hamadryad, 23(1), 63-68.

Dever, J. A., Fuiten, A. M., Konu, O., Wilkinson, J. A. (2012). “Cryptic torrent frogs of Myanmar: an examination of the Amolops marmoratus species complex with the resurrection of Amolops afghanus and the identification of a new species.” Copeia, 1, 57-76. [link]

Frank, N. and Ramus, E. (1995). A Complete Guide to Scientific and Common Names of Reptiles and Amphibians of the World. NG Publishing Inc., Pottsville, Pennsylvania.

Frost, D.R. (2013). Amphibian Species of the World: an Online Reference. Version 5.6 (9 January 2013). Electronic Database. American Museum of Natural History, New York, USA. Accessed February 19th, 2021 from https://amphibiansoftheworld.amnh.org/Amphibia/Anura/Ranidae/Amolops/Amolops-marmoratus

Li, P., Zhao, E., Dong, B. (2010). Amphibians and Reptiles of Tibet. Science Press, Beijing, China.

Lyu, Z., Zeng, Z., Wan, H., Yang, J., Li, Y., Pang, H., Wang, Y. (2019). “A new species of Amolops (Anura: Ranidae) from China, with taxonomic comments on A. liangshenensis and Chinese populations of A. marmoratus.” Zootaxa, 4609, 247-268. [link]

Mathew, R., Sen, N. (2010). Pictorial Guide to Amphibians of North East India. Zoological Survey of India, Kolkata, India.

Ngo, A., Murphy, R.W., Liu, W., Lathrop, A., and Orlov, N.L. (2006). ''The phylogenetic relationships of the Chinese and Vietnamese waterfall frogs of the genus Amolops.'' Amphibia-Reptilia, 27, 81-92.

Nokhbatolfoghahai, M., Conway, K. W., Atherton, L., Buddha, P. B., Jowers, M. J., Downie, J. R. (2020). “Larval description and developmental staging of Amolops tadpoles from Nepal, including ultrastructure of the oral disc and sucker.” Salamandra, 56, 317-328. [link]

Talukdar, S., Sengupta S. (2020). “Edible frog species of Nagaland” Journal of Environmental Biology, 41, 927-930. [link]

van Dijk, P.P. Chan-ard, T., Bordoloi, S., Borah, M.M., Asmat, G.S.M. 2004. "Amolops marmoratus." The IUCN Red List of Threatened Species 2004: e.T58221A11751482. https://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T58221A11751482.en. Downloaded on 19 February 2021.

Species Account Citation: AmphibiaWeb 2022 Amolops marmoratus: Pegu Torrent Frog <https://amphibiaweb.org/species/4656> University of California, Berkeley, CA, USA. Accessed Dec 26, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 26 Dec 2024.

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