Description
Microhyla xodangorum is a medium frog with a stocky body described from one female specimen with a total body length of 25.6 mm. The head is wider than long with the top of the head being flat. The snout is long, rounded in the profile and extends beyond the lower jaw. The nostrils are oval-shaped and are oriented laterally, aligned parallel to the dorsal stripe. The canthus rostralis is round and the loreal region is acute. The internarial distance is shorter than the interorbital distance. The eyes of the frog are small, protrude slightly out from the head, and feature a rounded pupil. There is no visible tympanum but there is a weak supratympanic fold that extends from the posterior corner of the eye to the insertion of the forelimb. The skin on the dorsum and dorsal limbs is mostly smooth but has evenly scattered flat tubercles. The tarsus is smooth. There are low tubercles around the cloaca. The dorsolateral edges are sharp. The ventrum is smooth except on the ventral surface of the thighs, which has a few tubercles. The forelimbs are short, roughly half of the total body length. The hands are half the length of the forelimbs. The prominent inner metacarpal tubercle is oval and the outer metacarpal is round. The slender, round, unwebbed fingers have weak dermal fringes and a relative finger length of I < IV < II < III, with the second finger being more than twice the length of the first. The fingertips expand into weak discs that have narrow peripheral grooves. The dorsal surfaces of the fingertips also have a median longitudinal groove that creates two scutes. There is one prominent, round subarticular tubercle on fingers I and II and two on fingers III and IV. When the long, slender hind limb is adpressed along the body, the tibiotarsal articulation extends well beyond the snout. The tibia is about 60% of the snout-vent length and the foot is longer than the tibia. There is no tarsal fold. The elongated, oval inner metatarsal tubercle is prominent and the oval outer metatarsal tubercle is distinct. The toes have distinct dermal fringes, a relative toe length of 1 < II = V < III < IV, and basal webbing with a formula of I 1½ – 2½ II 1¾ – 3 III 2¾ – 3¾ IV 4 – 2½ V. The toe tips are expanded into discs that are slightly larger than the finger discs. The toe tips also have longitudinal grooves. There is one prominent subarticular tubercle under toes I and II, two under toes III and V, and three under toe IV (Hoang et al. 2022).

DIAGNOSIS:

Microhyla xodangorum is similar to other species within the M. heymonsi group, but has a few distinct differences. Specifically, M. xodangorum is larger than M. hmongorum, M. ninhthuanensis, and M. pineticola. The presence of a round snout in M. xodangorum differentiates it from M. hmongorum, M. neglecta, and M. pineticola, which have tapered snouts, and from M. heymonsi, which has a pointed snout. Microhyla xodangorum is the only frog within the M. heymonsi group to possess nearly smooth dorsal skin, with small, flat tubercles evenly distributed across the dorsum, and also feature sharp dorsolateral edges. It is also the only frog within this group to feature a yellow and gray marbled belly, besides M. neglecta, which can be distinguished by its dark brown-black sides. Lastly, the long hind limbs in which the tibiotarsal articulation extends beyond the snout in M. xodangorum differentiates it from M. daklakensis, M. heymonsi, M. hmongorum, and M. ninhthuanensis, which have tibiotarsal articulations that do not extend past the snout (Hoang et al. 2022).

COLORATION:

In life, M. xodangorum has a beige dorsal coloration, overlaid with a dusting of dark brown speckling. Some speckling forms a triangle between the eyes that extends posteriorly to create a faint hourglass pattern across the back, and encasing a distinct, O-shaped black circle in the center of the back. The flanks and lateral portion of the head are dark brown. The supratympanic fold and area around the armpit are beige. Between the upper jaw and eye there are some small beige spots. The dorsal surface of the limbs has a background color of beige with dark brown crossbars and some black spots along the thigh. On the ventral side, the belly and chest are yellow with gray mottling along the edges of the belly. The chin is a mottled gray that features a creamy stripe that does not reach the center of the chest. The eyes of this frog are dichromatic, featuring a golden color with black reticulations on the upper third of the iris, and a darker copper color in the lower two-thirds with dark pigmentation in the anterior and posterior corners (Hoang et al. 2022).

In preservative, the beige coloration fades to a whitish-gray on the dorsum and a dark gray on the ventral side. The patterning on the dorsal side remains unchanged, but the brown coloration fades from brown to dark gray, and the iris turnes completely black (Hoang et al. 2022).

VARIATION:

At the time of the species description, only a single female specimen of M. xodangorum was utilized (Hoang et al. 2022), and thus no variation was available.

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Viet Nam

View distribution map in BerkeleyMapper.

Microhyla xodangorum is found in the Central Highlands of Vietnam, within the Kon Tum Plateau in the Kon Tum Province. The specimen used for the species description was collected along the banks of a small stream in a humid (97% relative humidity) dipterocarp forest, located at 1,250 m above sea level. More studies are necessary to identify the full range of this species, but it is likely endemic to the Central Highlands in Vietnam (Hoang et al. 2022).

Life History, Abundance, Activity, and Special Behaviors
The holotype was collected at night between 19:00 and 23:00. Only a single adult female was collected, and advertisement strategies, larval stages, and egg descriptions were unknown at the time of the species description (Hoang et al. 2022).

Comments

PHYLOGENETIC RELATIONSHIPS:

References
Hoang, C. V., Nguyen, T. T., Phan, T. Q., Pham, C. T., Ninh, H. T., Wang, B., Jiang, J., Ziegler, T., and Nguyen, T. Q. (2022). Distribution pattern of the Microhyla heymonsi group (Anura, Microhylidae) with descriptions of two new species from Vietnam. European Journal of Taxonomy 846, 1–41. [link]

Species Account Citation: AmphibiaWeb 2024 Microhyla xodangorum: Xodang Narrow-mouth Frog (English); Nhái bầu xơ đăng (Vietnamese) <https://amphibiaweb.org/species/9587> 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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