Description
Vietnamophryne cuongi is known from two female specimens with snout-vent lengths of 16.9 and 18.1 mm and one juvenile with a snout-vent length of 14.2 mm. They have a stout, miniaturized body with a head that is wider than long. The snout is rounded in the dorsal view and in the lateral view, it is truncated. The snout length is longer than its eye length. The rounded nostril is positioned laterally and at about half the distance from the tip of the snout to the eye. The dorsal surface of the head is relatively convexed, and the distinct canthus rostralis is rounded. The loreal region is concave. The medium-sized eyes have round, horizontal pupils and slightly protrude in both dorsal and lateral views. The relatively large, distinct tympanum is rounded and separated from the eye. The tympanic rim is not raised above the temporal area. The glandular supratympanic fold is prominent (Nguyen et al. 2021).

The short forelimbs are one-third the length of the hind limb length. The hands are almost one-third the length of the forelimb length. There are two palmar tubercles with both the inner and outer palmar tubercle being rounded and smooth, but the outer palmar tubercle is slightly longer than the inner palmar tubercle. The supernumerary palmar tubercles are not present. The fingers are short and round in a cross-section view. The well-developed first finger is less than half the length of the second finger. Relative finger lengths are: I < IV < II < III. The webbing and dermal fringes are not present. All fingertips are rounded, but the tips of the three outer fingers are not expanded and do not have disks or terminal grooves. The longitudinal furrow on the dorsal surface of the fingers is not present. The subarticular tubercles of the fingers are not obvious (Nguyen et al. 2021).

The hind limbs are short and thick, with the tibia length being less than half of snout-vent length. The tibiotarsal joint of the adpressed limb reaches the level of the eye. The foot length is almost the same length as the tibia. The tarsus is smooth with no tarsal fold present. There is a single metatarsal tubercle with a round and flat inner metatarsal tubercle. The toes are rounded in a cross-section view, and have relative toe lengths of: I < II < V < III < IV. The tips of all of the toes are round, but the tips of toes III and IV are slightly extended. Terminal grooves and dermal fringes are not present on the toes. No toe webbing is present. The subarticular tubercles of the toes are not obvious (Nguyen et al. 2021).

The skin on the anterior dorsal and dorsolateral surfaces are smooth. Small tubercles are prominent on the lateral parts of the dorsum, sacral area, and dorsal surfaces of the hind limbs. The dorsal surface of the forelimbs and the upper eyelids are smooth. The supratympanic folds have low glandular ridges. The ventral sides of the trunk and head are smooth. There is a distinct dermal ridge on the midline of the head dorsal surface, which runs from the tip of the snout to the sacral area (Nguyen et al. 2021).

DIAGNOSIS

COLORATION

In preservative, the dorsal surface of V. cuongi is gray with white-gray spots, and the ventral is white with dark-gray marbling. The marbling is denser at its anterior and more dispersed at the thighs, vent area, and chest (Nguyen et al. 2021).

VARIATION

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Viet Nam

View distribution map in BerkeleyMapper.

At the time of the species description, V. cuongi was endemic to Ba Vi National Park, Hanoi, Vietnam. This species was first reported to be found near a small pond with plant litter in an evergreen tropical forest at elevations between 975 - 1106 m (Nguyen et al. 2021).

Life History, Abundance, Activity, and Special Behaviors
As of 2023, there is very limited information regarding V. cuongi. The sample size of the species was very small, and focused on their morphology and genetics, not their lifestyle. However, the records of Vietnamophryne species found members of the species in soil and tree trunks. This suggests that they have a semi-fossorial lifestyle. However, the frogs lack any digging methods. Further research is required, since fossorial frogs of the Indochina region have not been extensively researched (Poyarkov Jr. et al. 2018, Nguyen et al. 2021).

Larva
The genus Vietnamophryne belongs to the family Microhylidae, and subfamily Asterophryinae. Based on this fact, it is likely that, like other members of the subfamily, V. cuongi exhibits direct development (Poyarkov Jr. et al. 2018, Nguyen et al. 2021).

Trends and Threats
There are very few specimens of V. cuongi. The specimens have only been found in Ba Vi National Park. The national park is home to various amphibians, many which are in serious threat from deforestation. Because of its limited range, threat of habitat loss, and rarity, the authors of the species description proposed that V. cuongi be listed as “Endangered” in the IUCN Red List (Nguyen et al. 2021).

Relation to Humans
As of 2023, there are no recorded or known usage by humans.

Possible reasons for amphibian decline

Habitat modification from deforestation, or logging related activities

Comments

PHYLOGENETIC RELATIONSHIPS:

ETYMOLOGY:

The species epithet, “cuongi,” is in honor of Dr. Pham The Cuong from the Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology in Hanoi. Dr. Pham The Cuong has contributed scientific work focused on the amphibian diversity of Vietnam (Nguyen et al. 2021).

References
Nguyen, T.V., Chung V.H., Jianping, J., Orlov, N.L, Ninh, H.T., Nguyen, H.Q, Nguyen, T.T, and Ziegler, T. (2021). A new species of Vietnamophyrne with an extended description of Vietnamophryne orlovi. Russian Journal of Herpetology, 28(6), 355-368. [link]

Poyarkov Jr., N.A., Suwannapoom, C. Pawangkhanant, P., Aksornneam, A., Duong, T.V., Korost, D.V., and Che J. (2018). A new genus and three new species of miniaturized microhylid frogs from Indochina (Amphibia: Anura: Microhylidae: Asterophryinae). Zoological Research, 39(3), 130-157. [link]

Species Account Citation: AmphibiaWeb 2023 Vietnamophryne cuongi: Cuong’s Dwarf Frog <https://amphibiaweb.org/species/9477> University of California, Berkeley, CA, USA. Accessed Apr 23, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 23 Apr 2024.

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