Description

DESCRIPTION:

Odorrana mutschmanni is a medium-to-large sized frog with a snout-vent length of 85.8 - 91.6 mm in males and 108.7 - 110.1 mm in females. The head is longer than it is wide with a round snout in the dorsal view that projects over the lower jaw. The nostrils are lateral and are closer to the tip of the snout than the eyes. This species has a distinct canthus rostralis and the loreal region slightly depressed and slanted. The eye diameter is shorter than the length of the snout. The pupils are horizontally oval and the interorbital distance is shorter than the internarial distance. The tympanum is round, very apparent, and about 70% of the diameter of its eye. There is a fold above the tympanum and spinules are present on the anterior and posterior edges of the tympanums. There are no vocal sacs present. The hand length of this species is over half the length of its forelimb length. The inner metacarpal tubercle is elongated and oval in shape while the outer metacarpal is small. The relative finger lengths are II < I < IV < III. There is undeveloped webbing on the fingers, and the tips of the fingers expand into discs with circummarginal grooves. The disc of finger III is over twice the width of the phalanges and about 40% of the diameter of the tympanum. In males, Finger I has an elongated nuptial pad. This species has round, subarticular tubercles with a formula of 1, 1, 2, 2. The tibia is approximately five times longer than it is wide and is longer than the thigh. There are no outer metatarsal tubercles but the inner metatarsal tubercle is elongated and oval. Their relative toe lengths are I < II < III < V < IV and the webbing formula is I 0 - 00 II - 0 III 0 - ½ IV ½ - 0 V. The tips of toes also expand into discs with circummarginal grooves similar to the fingers. The width of the disc on the IV toe is narrower than the width of the disc on the III finger and approximately twice the width of the phalanges. There are also bulging subarticular tubercles present in a formula of 1, 1, 2, 3, 2. The upper surface of the head and anterior part of the body are smooth in texture, while the posterior parts and flanks have tubercles. The throat, chest, belly, and ventral surface of the thighs are also smooth. The limbs are granular on the dorsal surface. Spinules are present on the sides of the body but there is no dorsolateral fold present (Pham et al. 2016).

DIAGNOSIS:

Odorrana mutschmanni is differentiated from other members of the genus by being generally larger in size, having black bars on the lips, lacking vocal sacs, lacking dorsolateral folds, and having a green dorsum. When compared to other members of the O. andersonii species group, which includes O. mutschmanni along with O. andersonii, O. grahami, O. jingdongensis, O. junlianensis, O. kwangwuensis, O. margaretae, and O. wuchuanensis, O. mutschmanni can be differentiated by a variety of of adult morphological structures, coloration, and egg morphology. More specifically, O. mutschmanni is larger than O. kuangwuensis and O. wuchuanensis. It also has a larger tympanum diameter to eye diameter ratio than O. andersonii, O. grahami, O. jingdongensis, O. junlianensis and O. kuangwuensis and a smaller ratio than O. wuchuanensis. The large dark spots on the ventral surface of O. mutschmanni differentiate it from the immaculate white on O. andersonii, O. grahami, O. jingdongensis, from the small dark spots in O. margaretae, and from the sparse black spots of O. kuangwuensis. The lack of spines on the males' chest differentiate O. mutschmanni from O. andersonii, O. grahami, O. jingdongensis, O. junlianensis, and O. margaretae. Additionally, the lack of spines on the dorsal surface of the arm in O. mutschmanni differentiates it from O. wuchuanensis. Odorrana mutschmanni has a disc on finger III that is more than twice the width of the base of the phalange, which differentiates it from from O. andersonii, O. grahami, O. jingdongensis, O. junlianensis, O. kuangwuensis, and O. margaretae. More developed toe webbing in O. mutschmanni differentiated it from O. margaretae. The absence of external vocal sacs in O. mutschmanni differentiates it from O. junlianensis. A smooth dorsal surface of the head and anterior part of the body and brown flanks and limbs in O. mutschmanni differentiate it from O. wuchuanensis. Lastly, unpigmented eggs in O. mutschmanni differentiate it from O. andersonii, O. junlianensis, and O. margaretae (Pham et al. 2016).

COLORATION:

Live O. mutschmanni have a green dorsal coloration with dark brown spots and a grey throat and chest. The tympanum is dark brown and there are black bars present on the lips. Their irises are black. The side of the head and flanks are a greyish-brown coloration accompanied by dark brown spots. The upper surface of the fore- and hind limbs display dark crossbars over the greyish brown coloration while the ventral surface consists of large, dark brown spots. The ventral surface of the belly and limbs have a network of dark spots with white edging. The webbing of the toes are dark brown and the spinules on the flank are ivory (Pham et al. 2016).

When O. mutschmanni is preserved, the dorsal surface is brown while the flanks are a cream color with large spots. The lips continue to display black bars, the throat and chest remain grey, and the toe webbing remains brown. The dorsal surfaces of the fore- and hind limbs are brown in color with the pattern of dark crossbars. Large black spots remain on the ventral surfaces of the belly and limbs (Pham et al. 2016).

VARIATION:

Females are typically larger than the males (Pham et al. 2016).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Viet Nam

View distribution map in BerkeleyMapper.

At the time of the species description, this species was only known from one locality in Cao Bang Province in the northeastern region of Vietnam at an elevation of 447 m. Odorrana mutschmanni appears to be closely associated with limestone or karst environments in hardwood forests with shrubs and vines. The majority of the specimens were found on boulder formations in the karst habitat, very few were located in the pools of water, and most were found about 0.5 - 1.0 m above the ground. It is assumed that this species could possibly be found in nearby karst formations of Ha Giang Province, Vietnam as well as in Guangxi and Yunnan provinces of China (Pham et al. 2016).

Life History, Abundance, Activity, and Special Behaviors

Odorrana mutschmanni is a terrestrial and nocturnal species that is commonly found on boulders and occasionally in the water. The species has rudimentary webbed feet, which suggests that they do not spend much time in the water, but are able to swim when they do enter the water (Pham et al. 2016).

Odorrana mutschmanni has no external vocal sac, which suggests that they do not produce calls (Pham et al. 2016).

Females lays eggs that are completely unpigmented (Pham et al. 2016).

Trends and Threats

Due to the minimal information published about this species, it is difficult to determine its abundance. However, based on information from closely related Odorrana species, it is likely that O. mutschmanni is not highly abundant, in decline, and possibly endangered (IUCN 2020).

Odorrana mutschmanni is threatened by human exploitation of the habitat including quarrying for cement and road construction, agriculture expansion, illegal timber logging (Pham et al. 2016).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Habitat fragmentation

Comments

PHYLOGENETIC RELATIONSHIPS:

Maximum Parsimony, Maximum Likelihood, and Bayesian Inference analyses on 12S and 16S mtDNA fragments indicate that O. mutschmanni is nested within the O. andersonii group and is sister to O. wuchuanensis. It is highly divergent from its sister species with the minimum pairwise genetic divergence being approximately 4.3%. The clade of these two species is sister to a clade composed of O. andersonii, O. daorum, O. grahami, O. hmongorum, O. jingdongensis, O. junlianensis, O. kuangwensis, and O. margaretae (Pham et al. 2016).

Convergent evolution has made it difficult to determine the relationships between species in the genera Amolops, Huia, and Odorrana. This ongoing debate has not yet been resolved, with species often being moved between these genera (Arifin et al. 2021).

References

Arifin, U., Chan, K. O., Smart, U., Hertwig, S. T., Smith, E. N., Iskandar, D. T., Haas, A. (2021). “Revisiting the phylogenetic predicament of the genus Huia (Amphibia: Ranidae) using molecular data and tadpole morphology.” Zoological Journal of the Linnean Society 193(2): 673–699 [link]

IUCN 2020. The IUCN Red List of Threatened Species. “Odorrana” Version 2020-3. https://www.iucnredlist.org/search?query=Odorrana&searchType=species Downloaded on 2/19/2021.

Pham, C. T., Nguyen, T. Q., Le, M. D., Bonkowski, M., Ziegler, T. (2016) “A new species of Odorrana (Amphibia: Anura: Ranidae) from Vietnam,” Zootaxa 4084(3), 421-435. [link]

Species Account Citation: AmphibiaWeb 2022 Odorrana mutschmanni: Mutschmann's Frog <https://amphibiaweb.org/species/8457> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

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