Microhyla nanapollexa Bain & Nguyen, 2004

Hoang, Chung Van, Pham, Cuong The, Nguyen, Truong Quang, Phan, Tien Quang, Ziegler, Thomas, Orlov, Nikolai, Jiang, Jianping & Do, Dang Trong, 2025, A new species of Microhyla (Amphibia: Anura: Microhylidae), with an extended description of Microhyla nanapollexa from Vietnam, Zootaxa 5566 (2), pp. 347-369 : 352-354

Microhyla nanapollexa Bain & Nguyen, 2004

( Figs. 2 , 3 ; Tables 2 )

Specimens examined. (n = 2), one adult male IEBR A.6269 (Field number 04287) and one adult female IEBR A.6270 (Field number KP2023.52 ), collected by C. V. Hoang et al. in April 2023 in the forest of Kon Plong District, Kon Tum Province, Vietnam (14°39'53.9"N 108°15'59.1"E, at an elevation of 1260 m a.s.l.) .

Description of specimens examined. Morphological characters of the specimens from Kon Tum Province, Vietnam, match the description of Bain & Nguyen (2004): Size small (SVL 15.43 mm in male; 16.02 mm in female); habitus slender, head longer than wide (HL/HW 1.10 in male, 1.15 in female); snout round, slightly protruding beyond margin of lower jaw, longer than diameter of eye (SL/ED 1.56 in male; 1.65 in female); eyes protuberant, pupil round; dorsal surface of head flat; canthus rostralis round, distinct; loreal region oblique, flat; nostril round, lateral, on canthus rostralis, closer to tip of snout than to eye (NED/SL 0.60 in male, 0.56 in female); interorbital distance wider than internarial distance (IOD/IND 1.61 in male, 1.62 in female) and wider than upper eyelid width (IOD/UEW 1.85 in male and female); tympanum hidden; vomerine teeth absent, tongue round posteriorly, free for approximately two thirds its length; slit like openings to a median vocal sac.

Forelimbs relatively short, shorter than snout vent length (FLL/SVL 0.74 in male, 0.78 in female); hand shorter than half of forelimb length (HAL/FLL 0.40 in male, 0.38 in female); fingers slender, free of webbing, dorsoventrally flattened, fingers with weak skin fringes on finger II and III; nuptial pad absent on male finger I; partially free nub just proximal to finger II (1FLO/2FLO 0.20 in male, 0.21 in female); finger II slightly longer than finger IV length (2FLI/4FLI 1.06 in male, 1.04 in female), and much shorter than the third (2FLI/3FLI 0.60 in male and female); relative finger lengths: I<II≤IV<III; tip of finger I round, not enlarged; narrow peripheral grooves present on fingers II, III and IV; grooves on dorsal surface of disks present in fingers II, III, IV, absent in finger I; relative finger disk widths II<IV<III; subarticular tubercles on fingers distinct, round, formula 1:1:2:1 (given for fingers I:II:III:IV, respectively); two round, flat palmar tubercle.

Hindlimbs slender, twice as long as snout-vent length (HLL/SVL 1.92 in male, 2.07 in female), tibia longer than half of snout-vent length (TL/SVL 0.63 in male, 0.68 in female); tibiotarsal articulation reaching beyond snout when limb adpressed along body; foot longer than tibia (FL/TL 1.43 in male, 1.38 in female); relative toe lengths: I<II<V<III<IV; tarsus smooth, inner tarsal fold absent; tips of all toes slightly dilated, forming truncated disks, disks of all toes with peripheral grooves, dorsal surface of toe disks II–V with short median longitudinal grooves; relative toe disk widths I<V<II<III=IV; webbing formula I1–2II1–2½III2½–2½IV2½–1V; subarticular tubercles on toes distinct, round, formula 1:1:2:3:2 (for toes I:II:III:IV:V, respectively); inner metatarsal tubercle oval; outer metatarsal tubercle absent.

Skin on dorsum relatively smooth with low, round tubercles concentrated on the outer edge, flanks, below and posterior to eye; dorsolateral folds distinct in adult male; cloaca unmodified, directed posteriorly, at upper level of thighs; supratympanic fold indistinct; lateral side of head smooth; ventral surface of body and limbs smooth, vent area smooth.

Coloration in life. Dorsal surface greyish brown to light brown with a dark brown or brown spear-shape marking, running from the posterior eye to the groin; black spear-shape marking border, or just two black spots on either side of the spear-shape marking; a black broken streak below dorsolateral folds; black streak-shape marking present on the groin region in adult male; a light brown streak from posterior corner of eye to arm insertion; dorsolateral surfaces of arm and fingers dark brown with a small black bar near the wrist; dorsal surfaces of thigh, tibia, tarsus and toes brown with dark brown cross bars on each hindlimb; throat and chest dark grey with intense small white mottling, belly and limbs ventrally lighter with white marbling mixed with black spots; pupil black, iris copper ( Fig. 2 ).

Coloration in preservative. In ethanol, dorsal coloration changed to dark greyish brown, ventral surface of chest, belly, and limbs greyish beige; dorsal pattern, dark spots on dorsum and stripes on dorsal surface of limbs unchanged, dark brown pattern changed to dark grey; pupil white, iris completely black ( Fig. 3 ).

Extended diagnosis. Microhyla nanapollexa is characterized by having a small body size ( SVL 15.43 mm, n = 1 male; 16.02–16.63 mm, n= 2 females); body habitus slender; snout round; skin on dorsum relatively smooth with low, round tubercles concentrated on the outer edge, flanks, below and posterior to eye; venter smooth; vertebral skin ridge and dorsomedial stripe absent; superciliary tubercles absent; supratympanic fold indistinct; fingers slender, free of webbing, with weak dermal fringes on fingers II and III; nuptial pad absent on male finger I; partially free nub just proximal to finger II; grooves on dorsal surface of disks present in fingers II – IV; two round, flat palmar tubercles; hindlimbs long, tibiotarsal articulation of adpressed limb reaching well beyond snout; toe webbing formula I1–2 II1–2 ½ III2 ½–2½ IV 2 ½–1 V; inner metatarsal tubercle oval; outer metatarsal tubercle absent; dorsal surface greyish brown to light brown with a dark brown or brown spear shape marking, running from the posterior eye to the groin; a black broken streak below dorsolateral folds; black streak shape marking absent or present on the groin region; belly and limbs ventrally lighter with white marble mixed with black spots; pupil black, iris copper in life.

Distribution. Microhyla nanapollexa is currently known from the type locality in Tra My District, Quang Nam Province and Kon Plong District, Kon Tum Province, Vietnam at elevations between 1260 and 1480 m a.s.l.

Figures

FIGURE 2. Microhyla nanapollexa dorsolateral view (A) and ventral view (B) in life (IEBR A.6270, female). Photos by C.V. Hoang.

FIGURE 3. Dorsal view (A) and ventral view (B) of the female specimen (IEBR A.6270) of Microhyla nanapollexa in preservative. Scale bar = 7 mm. Photos by C.V. Hoang.