Limnonectes splendissimus, Le & Nguyen & Murphy & Tran & Nguyen & Che, 2025

Limnonectes splendissimus sp. nov.

Holotype. ITBCZ 8674 , an adult male ( Figs. 3 View FIGURE 3 & 4 View FIGURE 4 ), collected from Gung Re Commune , Di Linh District, Lam Dong Province, Vietnam; coordinates 11 o 27’11.6”N, 108 o 05’32.3”E; elevation 1369 m a.s.l. by Manh V. Le and Tuan M. Nguyen, on 22 September 2023. GoogleMaps

Paratypes. Seven specimens: ITBCZ 8675 , 8676 (two adult males, Fig. 5A–D View FIGURE 5 ), ITBCZ 8677 (subadult male, Fig. 5E, F View FIGURE 5 ), ITBCZ 8678 (adult female), collected by the same collectors, on the same date and site as the holotype; GoogleMaps ITBCZ 8679 (adult female, Fig. 5G, H View FIGURE 5 ) collected from Voi Mountain , Hiep Thanh Commune, Duc Trong District, Lam Dong Province, Vietnam; coordinates 11 o 49’39.4”N, 108 o 24’29.2”E; elevation 1611 m a.s.l by Manh V. Le and Tuan M. Nguyen, on 23 September 2023; GoogleMaps ITBCZ 3626 (subadult female, Fig. 5I, K View FIGURE 5 ) and ITBCZ 3627 (juvenile, Fig. 5L, M View FIGURE 5 ) collected from Voi Mountain , Hiep Thanh Commune, Duc Trong District, Lam Dong Province, Vietnam; coordinates 11 o 49’39.4”N, 108 o 24’29.2”E; elevation 1488 m a.s.l by Luan T. Nguyen, Manh V. Le, Tuan M. Nguyen, Dzung T.T. Tran, on 25 February 2023. GoogleMaps

Diagnosis. The new species belongs to the genus Limnonectes based on both molecular analyses ( Portik et al. 2023) and morphological assessment because it has fang-like odontoid processes on its lower jaw, and with males being larger than females ( Emerson et al. 2000). Limnonectes splendissimus sp. nov. can be distinguished from all of its congeners by a combination of the following morphological characters: large body size (SVL 104.1–107.0 mm in adult males, 87.2–97.7 mm in adult females); head length longer than wide (HW/HL = 0.91± 0.01 in adult males, 0.87± 0.08 in adult females); males with increased head height and a nuptial pad on Finger I; tympanum distinct; eye diameter about three-fifths of tympanum-eye distance in adult males (ED/TED = 0.62±0.13) while longer than in adult females (ED/TED = 1.40±0.02); presence of vomerine teeth; odontoid developed (OH 8.0± 0.6 mm in adult males, 4.5± 0.9 mm in adult females); finger length relative III>I>II>IV, no webbing between fingers; relative toe lengths IV>III>V>II>I; toes webbed to distal of terminal phalanx, formula I0-0II0-0III0-0IV0-0V; throat pattern of juveniles distinct with black and white spots that cover both the throat and the anterior half of venter, posterior half of venter yellow.

Description of holotype. Adult male, large body size, SVL 105.4 mm; habitus robust with enlarged head (HL/SVL = 0.48); head length longer than wide (HW/HL = 0.91); snout round anteriorly in dorsal view, projecting beyond lower jaw; rostral length greater than eye diameter (RL 15.3 mm, ED 8.8 mm); nostril lateral, elongate, ovoid, closer to tip of snout than to eye (NS 6.1 mm, EN 9.4 mm); interorbital distance wider than internarial distance and upper eyelid width (IOD 10.8 mm, IND 8.2 mm, UEW 6.4 mm); canthus rounded; loreals concave; eye diameter approximately equal tympanum diameter (ED/TD = 1.05), eye closer to nostril than tympanum (EN 9.4 mm, TED 14.2 mm); tympanum distinct, slightly elongate, distance between tympanum to eye longer than eye diameter and tympanum diameter (TED 14.2 mm, ED 8.8 mm, TD 8.4 mm). Hypertrophied jaw musculature (adductors) visible on dorsum; supratympanic fold robust, extending from eye to angle of jaw; vomerine teeth on oblique ridges, deflected towards the inside of the choanae, the distance between vomerine teeth rows shorter than distance from vomerine and the choanae. Choanae oval, perpendicular to longitudinal axis of body. Odontoid robust at base tapering to pointed tips, length almost twice depth of mandible. Symphysial knob at mandibular symphysis. Tongue notched deep posterior, about one-fourth of the tongue.

Forelimbs. Arms medium in length, upper arm length (UAL) 21.0 mm, forearm length (FAL) 43.6 mm. Tips of finger rounded not expanded into discs with fingers pad elevated; finger length relative III>I>II>IV, no webbing between fingers; fringe on sides of finger I absent, distinct between fingers II–III, indistinct between fingers III–IV; subarticular tubercles prominent, round, formula 1, 1, 1, 1 for finger I, II, III, IV respectively; thenar tubercle at base of finger I large (TTL 5.1 mm), oval, distinct elevated forward; inner metacarpal tubercle at base of finger III (IMC 4.3 mm), slightly rounded; outer metacarpal tubercle small (OMT 3.9 mm), at base of finger IV, elongated; distinct nuptial pad present on finger I.

Hindlimbs. Robust and long (total length 181.4 mm). Tibia length longer than thigh length (FeL 52.6 mm; TBL 55.5 mm) and approximately 2.9 times of tibia wide. Tips of toes rounded not expanded into discs, no circummarginal groove, toe pads elevated; relative toe lengths IV>III>V>II>I; toes webbed to distal of terminal phalanx, formula I0-0II0-0III0-0IV0-0V; movable flap of skin distinct on postaxial side toe V from base of toe pad to the metatarsus; movable flap of skin on preaxial side of toe I from base of toe pad to the inner metatarsal tubercle continuing as distinct fold on distal half of tarsus; subarticular tubercles prominent, oval, elevated, formula 1, 1, 2, 3, 2 for toe I, II, III, IV, V, respectively; inner metatarsal tubercle elongated (IMT 6.2 mm) with elevated postaxial border; no outer metatarsal tubercle.

Skin. Body smooth in general; dorsal surface of head almost smooth, upper of eyelid with some tubercles; supratympanic fold distinct, extending from eye to angle of jaw; dorsolateral fold absent; dorsal surface of flanks rough scabrous with larger tubercles; dorsal surface of forelimbs smooth; dorsal surface hindlimbs smooth with distinctly small tubercles on half of shank and foot region; throat, chest, belly and ventral surface of thighs smooth, numerous white distinctly small tubercles focus on pre-cloacal region.

Coloration in life. Dorsal surface dark reddish brown with black and interrupted mottling patterns; pupil rounded, black, and reflects orangy-red under flash photography ( Fig. 3A View FIGURE 3 ); light orange interorbital bar, bordered posteriorly by black; iris with mixed between light orangish red and light greyish spots; tympanums particolored with upper black and lower light reddish brown; rostrum reddish brown; upper lip with bars that extend all the way to behind the eye and the orangy-red section is just beneath the tympanum area; lower lip with black and white barring and orange spots; flank surfaces reddish brown with some black spots, orangish red tubercles, and two yellow spots near the armpit and groin; dorsal and anterior surfaces of limbs reddish brown and orangish red, and interrupted with fainted black crossbars; dorsal surface of fingers and toes orangish red with black spots; posterior surface of forelimbs black with light spots; posterior surfaces of thighs pattern mixed between yellow or light yellow with black spots; throat surface pattern grey and white, outer margin mixed with orange, white and black barring, and black spots near base on forelimbs; middle part of ventral surface white, light golden on latter half, with yellow outer margins; ventral surface of forelimbs white; ventral surface of hindlimbs reddish brown or brown with some grey lines, and outer margin yellow; ventral surface of forefoots and hindfoots black ( Fig. 3 View FIGURE 3 ).

Coloration in preservation. Dorsum, rostrum, and limbs surfaces faded to brown; surfaces of post-dorsal part, shank, and foot with white small tubercles remain distinct; posterior surfaces of thighs faded to dark grey and some bright brindles; throat surface pattern faded to grey and cream, outer margin faded to cream with black barring; ventral surface of limbs cream ( Fig. 4 View FIGURE 4 ).

Variation. Variations in measurements and morphological features of the type series are provided in Table 5 View TABLE 5 and color variations in life and preservation follow in Figs. 5 View FIGURE 5 & 6 View FIGURE 6 . Body color in life varies between individuals within the type series ( Fig. 5A, C, E, G, I, L View FIGURE 5 ). Juvenile ITBCZ 2627 has a very distinct belly with black and white pattern that covers both the throat and half of ventral, a half ventral latter yellow ( Fig. 5L, M View FIGURE 5 ). In subadult male and female ITBCZ 8677 and ITBCZ 3626, throat surface pattern faded to grey and white, while the ventral surface is generally yellow ( Fig. 5F, K View FIGURE 5 ). In adult males and female ITBCZ 8675, 8676 and 8679, the ventral surfaces change from yellow to ochre, yellowish-brown or beige ( Fig. 5B, D, H View FIGURE 5 ). Body color in preservation changed from brown to grey ( Fig. 6A, C, E, G, I, L, N View FIGURE 6 ). Throat surface pattern in juvenile and subadults is distinct ( Fig. 6K, M, O View FIGURE 6 ) but faded in adult males and females ( Fig. 6B, D, F, H View FIGURE 6 ).

Sexual dimorphism. Adult males have larger body sizes than females (SVL 104.1–107.0 mm in adult males vs. 87.2–97.7 mm in adult females); an increased head height; a nuptial pad on finger I present (vs. absent); tympanum-eye distance greater than the eye diameter in adult males and shorter in females (ED/TED = 0.62± 0.13 in adult males vs. 1.40± 0.02 mm in adult females); odontoid height tends to be more prominent (OH 8.0± 0.6 mm in adult males vs. 4.5± 0.9 mm in adult females). Juveniles, subadults, and adults represent differences in throat surface pattern and ventral surface color ( Fig. 5 View FIGURE 5 ).

Etymology. Name from Latin “splendissimus ” refers to the splendid coloration on the underside of young individuals. We recommend “Splendid Fanged Frog” and “Ếch nhẽo đốm” as the common English name and Vietnamese name of the new species, respectively.

Natural history and Distribution. The new species is currently known from type locality in Lam Dong Province, southern Vietnam ( Fig. 7 View FIGURE 7 ). All specimens were discovered between 20:00 and 24:00 in evergreen forests at elevations exceeding 1300 m a.s.l. The holotype and paratypes ITBCZ 8675–78 were obtained from a small swamp after rainfall ( Fig. 8A View FIGURE 8 ). Paratype ITBCZ 8679 was collected from a larger swamp ( Fig. 8B View FIGURE 8 ). Paratypes ITBCZ 2627 , 3626 were retrieved from a water hole along the stream. Females carry eggs in September, and juveniles were found in February .

Comparisons. Limnonectes splendissimus sp. nov. has a visible tympanum, and therefore it can be distinguished from the following species that do not have a visible tympanum: L. bannaensis ( Ye et al. 2007) ; L. deinodon Dehling ( Dehling 2014); L. fastigatus ( Stuart et al. 2020) ; L. isanensis McLeod, Kelly & Barley ( McLeod et al. 2012); L. jarujini Matsui, Panha, Khonsue & Kuraishi ( Matsui et al. 2010); L. kiziriani ( Pham et al. 2018) ; L. macrognathus (Boulenger) ( Boulenger 1917) ; L. megastomias McLeod ( McLeod 2008); L. nguyenorum ( McLeod et al. 2015) ; L. phuyenensis ( Pham et al. 2020) ; L. taylor Matsui, Panha, Khonsue & Kuraishi ( Matsui et al. 2010); and L. utara ( Matsui et al. 2014) .

Among species having a visible tympanum, L. splendissimus sp. nov. has a larger body size (with SVL 104.1– 107.0 mm in males and 87.2–97.7 mm in females) than the following species: L. coffeatus Phimmachak, Sivongxay, Seateun, Yodthong, Rujirawan, Neang, Aowphol & Stuart (SVL 37.9 mm in male and 38.1–42.1 mm in females; Phimmachak et al. 2018); L. dabanus (SVL 52.0–55.0 mm in males and 39.0 mm in female; Smith 1922), L. doriae (Boulenger) (SVL 41.4–55.0 mm in males and 39.4–50.3 mm in females; Yodthong et al. 2021), L. gyldenstolpei (SVL 51.1–68.4 mm in males and 23.0 in female; Andersson 1916; Aowphol et al. 2015), L. hascheanus (Stoliczka) (SVL 18.8–25.4 mm in males and 20.5–25.0 mm in females; Inger & Stuart 2010), L. khammonensis (Smith) (SVL 37.5 mm in female; Smith 1929), L. kohchangae (SVL 40.0–42.0 mm in males and 39.0–42.0 in females; Smith 1922), L. lauhachindai Aowphol, Rujirawan, Taksinum, Chuaynkern & Stuart (SVL 30.5–42.0 mm in males and 32.9–37.9 mm in females; Aowphol et al. 2015), L. limborgi (SVL 31.2 mm in male and 26.9–27.4 mm in females; Köhler et al. 2021), L. paramacrodon (Inger) (SVL up to 75 mm in males; Inger 1966), L. plicatellus (Stoliczka) (SVL 36 mm in male and 34 mm in female; Boulenger 1920), L. pseudodoriae Yodthong, Rujirawan, Stuart & Aowphol (SVL 42.6–48.2 mm in males and 36.0– 41.1 mm in females; Yodthong et al. 2021), L. quangninhensis (SVL 50.1–68.9 mm in males and 45.5–63.0 mm in females; Pham et al. 2017); and L. savan Phimmachak, Richards, Sivongsay, Seateun, Chuaykern, Makchai, Som & Stuart (SVL 39.0– 56.2 mm in males and 38.9–56.2 mm in females; Phimmachak et al. 2019). For the large-body size group, L. splendissimus sp. nov. differs from L. malesianus (Kiew) by having a smaller body size in males, with SVL up to 107.0 mm (vs. SVL up to 150 mm in males; Das et al. 2007) and by having toes fully webbed (vs. toes ¾ webbed; Das et al. 2007).

Limnonectes splendissimus sp. nov. is morphologically similar to L. blythii (Boulenger) . However, the new species can be distinguished from L. blythii by having smaller body size, with SVL 104.1–107.0 mm in males and 87.2–97.7 mm in females (vs. larger body size of both sexes, SVL from 110.0 mm to nearly 260.0 mm; Taylor 1962); by males having a nuptial pad on first finger (vs. absent; Taylor 1962); and by having a tympanum diameter approximately eye diameter with ratio TD/ED 0.95± 0.07 in males and 0.76± 0.02 in females (vs. greatest ratio TD/ ED 0.6; Taylor 1962).

Limnonectes splendissimus sp. nov. is most closely to related to L. poilani ( Fig. 9 View FIGURE 9 ). Measurements between the new species and L. poilani are provided in Table 4 View TABLE 4 . Limnonectes splendissimus sp. nov. can be distinguished from L. poilani by having larger body size, with SVL 104.1–107.0 mm in males and 87.2–97.7 mm in females (vs. SVL 84.1–89.3 mm in males and 67.5–69.9 mm in females; SVL 93.0 mm in male [ Bourret 1942]; SVL 58.5–93.1 mm in males and 53.7–79.6 mm in females [ Inger et al. 1999]); by having tympanum diameter approximately eye diameter with ratio TD/ED 0.95± 0.07 in males and 0.76± 0.02 in females (vs. ratio TD/ED 0.64± 0.07 in males and 0.66± 0.03 in females); by having smaller ratio between eye diameter and tympanum-eye, with ratio ED/TED 0.62± 0.13 in adult males and 1.40± 0.02 in adult females (vs. ED/TED 0.85± 0.11 in adult males and 1.77± 0.19 in adult females); and by juveniles having throat surface pattern very distinct with black and white spots that covers both the throat and anterior half of venter, and latter half of ventral yellow (vs. dark spots only in throat and ventral yellow-white, in juveniles; Fig. 10 View FIGURE 10 ).