Micryletta thongphaphumensis Cao, Suwannapoom, Kilunda, Wu & Che 2024, sp. nov.
Creators: name: Cao, Yu-Yang
name: Suwannapoom, Chatmongkon
name: Kasyoka Kilunda, Felista
name: Gao, Wei
name: Wu, Chun-Lian
name: Wu, Yun-He
name: Che, Jing
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Amphibia
Anura
Microhylidae
Micryletta
Micryletta thongphaphumensis

description: Micryletta thongphaphumensis Cao, Suwannapoom, Kilunda, Wu & Che sp. nov.
Figs 3, 4, 5
Micryletta inornata., Kurabayashi et al. 2011.
Etymology.
The specific name is a Latinized toponymic adjective in neuter gender derived from ‘‘ Thong Pha Phum’ ’ in reference to the type locality Thong Pha Phum District in Kanchanaburi Province, Thailand.
Suggested common name.
We propose “ Thong Pha Phum Paddy Frog ” as the common English name.
Type material.
Holotype (Figs 3, 4) • KIZ 024670, adult male from Thong Pha Phum District in Kanchanaburi Province, Thailand (15°11'52.72"N, 98°19'29.71"E; 242 m a. s. l.), collected by Chatmongkon Suwannapoom, Jing Che, Fang Yan, and Wei Gao on 5 August 2013.
Paratypes (Fig. 5) • KIZ 016763, KIZ 016768, KIZ 016771, and KIZ 016690, four adult females from Sai Yok Noi Waterfall in Kanchanaburi Province, Thailand (14°14'19"N, 99°03'30"E; 182 m a. s. l.), collected by Zhi-Yong Yuan and Chatmongkon Suwannapoom on 4 August 2014. KIZ 016769 adult male, with the same collection information as females.
Referred specimens.
One adult female KIZ 016762 and two adult males, KIZ 016764 and KIZ 016770, from the same location as paratypes.
Diagnosis.
Micryletta thongphaphumensis sp. nov. is assigned to the genus Micryletta based on the following combination of morphological traits: small body size; absence of vomerine teeth; tympanum small and externally visible; subarticular tubercles on fingers and toes prominent; three well-developed metacarpal tubercles; absence of webbing between fingers and toes (Dubois 1987; Fei et al. 2009). The new species differs from its congeners by a combination of the following characters: medium-sized within the genus (SVL 21.3–25.6 mm in males, n = 5; 24.4–29.7 mm in females, n = 4; Table 3); snout truncate in dorsal view; tympanum distinct; supratympanic fold absent; a black streak extending from tip of the snout to crotch; upper lip white; tibiotarsal articulation adpressed limb reaching level of tympanum; lack of webbing between fingers and toes; relative finger lengths: I <II <IV <III; relative toe lengths: I <II <V <III <IV; outer metatarsal tubercle absent; ventral skin of body and limbs smooth; brown marbling patterns on dorsal limbs; dorsal orange-brown with black spots (Fig. 4).
Description of the holotype
(Fig. 4, Table 3). Adult male, body size small (SVL = 25.6 mm), elongated oval-shaped; head wider than long (HW / HL = 1.2); canthus rostralis distinct, rounded; loreal region slightly concave; top of head relatively flat; snout slightly projecting beyond lower jaw, truncate in dorsal view, and bluntly rounded in profile; snout length longer than diameter of eye (SL / ED = 1.3); nostril round, closer to tip of snout than to eye (SN / EN = 0.6); internarial distance greater than upper eyelid width (INS / UEW = 1.6), and shorter than interorbital distance (INS / IOS = 0.5); upper eyelid width roughly equal one-third of interorbital distance (UEW / IOS = 0.3) and half of diameter of eye (UEW / ED = 0.5); eyes medium in size (ED / HL = 0.4); vomerine teeth absent; opening of vocal sac long cleft; tongue oval, with no notch at posterior tip; tympanum distinct, small (TD = 0.9 mm) and rounded; diameter of tympanum shorter than diameter of eye (TD / ED = 0.4); interorbital distance between anterior margins of eyes closer than that of posterior margins (IFE / IBE = 0.6); supratympanic fold absent.
Forelimbs slender and long, hand slightly longer than forearm length (HAL / FAL = 1.1); relative finger lengths: I <II <IV <III (FIL = 2.5 mm, FIIL = 3.4 mm, FIIIL = 6.1 mm, FIVL = 4.6 mm); tips of fingers round and not expanded to disks; subarticular tubercle on fingers rounded and prominent, subarticular tubercle formula: 1, 1, 2, 2; nuptial pad absent; webbing between fingers absent; three well-developed metacarpal tubercles at the base of outer three fingers, inner one rounded and smallest, outer metacarpal tubercle elongated, medial metacarpal tubercle large, oval and prominent.
Hindlimbs slender, tibia length shorter than half of snout-vent length (TL / SVL = 0.4), tibia length slightly shorter than foot length (TL / FL = 0.9); heels slightly overlapped when thighs are positioned at right angles to the body; tibiotarsal articulation adpressed limb reaching level of tympanum; tips of toes round and not expanded to disks; subarticular tubercles on toes rounded and prominent, formula: 1, 1, 2, 3, 2; relative toe lengths: I <II <V <III <IV (TIL = 2.4 mm, TIIL = 4.7 mm, TIIIL = 8.3 mm, TIVL = 11.2 mm, TVL = 6.6 mm); three small supernumerary tubercles at base of toes II – IV, smaller than proximal subarticular tubercles; inner metatarsal tubercle oval and distinct (IMT = 0.9 mm); outer metatarsal tubercle absent; webbing between toes absent.
Dorsum skin of body and limbs smooth without small tubercles; dorsolateral fold absent; ventral surface of throat, belly, forelimbs, and hindlimbs smooth; upper eyelid lacking tubercles; dorsal skin of body sparsely granular in life; vent area smooth.
Color of holotype in life (Fig. 3). Dorsum skin of body orange-brown with some scattered blackish black spots elongate; lateral sides of dorsum with brownish black stripes from snout to groin; subtle longitudinal median line present on dorsum; upper lip white, extending up to the anterior forelimb; lower lip puce with white mottling along the margins; dorsal surface of forearms orange-brown without brown marbling patterns; dorsal surface of hindlimbs orange-brown without dark transverse bands, brown marbling patterns clearly, extending to dorsal of fifth toe; finger and toes I – IV gray-brown with white mottling; groin, anterior and posterior parts of thigh, and lateral surfaces of shank and tarsus brown with a few fuzzy white spots; irregular white and brown spots on chest and lateral belly; iris bicolored, with upper third bronze and lower two-thirds dark brown.
Color of holotype in preservative (Fig. 4). Colors considerably faded; dorsum skin of body grey-brown with blackish black spots; the pattern generally remains unchanged; subtle longitudinal median line fuzzy on dorsum; upper lip, belly, and white spots turned to light grey.
Variation and sexual dimorphism (Fig. 5). The body sizes of males are smaller than females generally, although there is overlap in the ranges of values (male SVL 21.3–25.6 mm, female SVL 24.4–29.7 mm); translucent skin on belly through which the large bicolored white and black eggs are visible; dark-brown spots markings variable in density from few to many and most somewhat elongate rather than round; the shapes of spots varied; subtle longitudinal median line clear or fuzzy on dorsum.
Distribution and ecology.
Micryletta thongphaphumensis sp. nov. is currently known from the Thong Pha Phum District and Sai Yok Noi in Kanchanaburi Province, Thailand (Fig. 1). Considering that the region borders Myanmar, it is speculated that this species may also be present in Myanmar. Eggs were visible in the females we collected, thus indicating that August is the breeding season for this species. Other frog species were observed at the same location, including Microhyla mukhlesuri, M. heymonsi, Hylarana nigrovittata, Occidozyga martensii, Limnonectes jarujini, and Fejervarya limnocharis.
Morphological comparison.
We compared Micryletta thongphaphumensis sp. nov. to all other recognized species of the genus Micryletta (Tarkhnishvili 1994; Poyarkov et al. 2018, 2021; Alhadi et al. 2019; Das et al. 2019; Munir et al. 2020; Suwannapoom et al. 2020; Liu et al. 2021 a, b; Miller et al. 2021; Yang and Poyarkov 2021; Sankar et al. 2022).
Micryletta thongphaphumensis sp. nov. differs from M. hekouensis by its supratympanic fold absent (vs. supratympanic fold distinct); dorsum of upper arms and dorsum of body orange-brown with brown marbling patterns in life (vs. dorsum of upper arms golden, dorsum of hindlimbs solid black with brownish black stripes); tibiotarsal articulation adpressed limb reaching level of tympanum (vs. reaching front of eye); dermal ridges absent (vs. dermal ridges present under 2 nd to 4 th toes but indistinct).
Micryletta thongphaphumensis sp. nov. differs from M. steinegeri by snout length slightly longer than diameter of eye (vs. snout length shorter than diameter of eye); webbing between fingers and toes absent (vs. rudimentary webbing between toes); second finger shorter than fourth finger, relative finger lengths: I <II <IV <III (vs. second finger longer than fourth finger, relative finger lengths: I <IV <II <III); supratympanic fold absent (vs. distinct).
Micryletta thongphaphumensis sp. nov. differs from M. immaculata by dorsum orange-brown in life (vs. dorsum bronze brown to reddish brown); black stripes extending from tip of snout to crotch and dark brown spots on dorsum obvious (vs. dark brown spots and stripes on dorsum and flank absent); white stripes on upper lips present (vs. irregular white spots along upper lips present); supratympanic fold absent (vs. distinct and lower margin of supratympanic fold black); webbing between toes absent (vs. webbing between toes basal and poorly developed).
Micryletta thongphaphumensis sp. nov. differs from M. menglienica by supratympanic fold absent (vs. distinct); dermal ridges absent (vs. dermal ridges present under 2 nd to 4 th toes but indistinct); dorsum of forelimbs and body orange-brown in life (vs. dorsum of forelimbs light yellow, dorsum of hindlimbs the same color as dorsum of body); ventral side of head and chest brown (vs. ventral side of head and chest greyish brown or purple grey); tibiotarsal articulation adpressed limb reaching level of tympanum (vs. reaching eye or between eye and tympanum).
Micryletta thongphaphumensis sp. nov. differs from M. aishani by white stripes on upper lips (vs. ash-grey mottling along the margins of the upper lips); dorsum orange-brown with many large or small scattered blackish black spots in life (vs. dorsum reddish-brown with few scattered blackish-brown spots on posterior parts of the back and near the groin); tibiotarsal articulation adpressed limb reaching level of tympanum (vs. reaching up to the level of armpit); lateral sides of dorsum with brownish black stripes from snout to groin (vs. blackish-brown streak extending from snout to lower abdomen); fifth toe longer than second toe, relative toes lengths: I <II <V <III <IV (vs. fifth toe shorter than second toe, relative toe lengths: I <V <II <III <IV).
Micryletta thongphaphumensis sp. nov. differs from M. sumatrana by tibiotarsal articulation adpressed limb reaching level of tympanum (vs. tibiotarsal articulation reaching front of eye); upper lip white (vs. cream spots between lip and axilla); supratympanic fold absent (vs. supratympanic fold thick, rounded, glandular, curving from posterior corner of the eye to shoulder); brown marbling patterns on tibia and tarsal (vs. complete and incomplete dark brown cross bands on tibia and tarsus); dorsum orange-brown with large or small scattered blackish black spots (vs. dorsal coloration of body golden brown with some irregular dark spots and dark thin vertebrae line).
Micryletta thongphaphumensis sp. nov. differs from M. erythropoda by the outer metatarsal tubercle absent (vs. presence of an outer metatarsal tubercle); orange-brown dorsum in life (vs. brick-reddish dorsum); webbing between toes absent (vs. toes with rudimentary web); second finger shorter than fourth (vs. second finger equal to fourth).
Micryletta thongphaphumensis sp. nov. differs from M. inornata by tibiotarsal articulation adpressed limb reaching level of tympanum (vs. reaching the eye); dorsum orange-brown with large or small scattered blackish spots (vs. dorsum brownish-grey with a silver tinge and irregular blackish-brown blotches of variable size); lateral sides of dorsum with continuous brownish black stripes from snout to groin (vs. presence of a discontinuous lateral blackish-brown streak from the tip of the snout to near the groin); throat brown with irregular fuzzy white spots (vs. throat light reddish-grey without prominent spots); dorsal of limbs with black marbling patterns (vs. dorsal of limbs with irregular golden yellow spots).
Micryletta thongphaphumensis sp. nov. differs from M. dissimulans by hand wider than long (vs. head longer than wide); snout length longer than diameter of eye (vs. diameter of eye equal to snout length); dorsal orange-brown with black spots (vs. dorsal shagreened with irregular-shaped brown blotches edged in beige, no black spots on dorsum); without large black spot behind eye (vs. large black spot behind eye); lateral sides of dorsum with brownish black stripes from snout to groin (vs. two large black blotches in axillary and inguinal areas on each side); white patches on lips (vs. absent).
Micryletta thongphaphumensis sp. nov. differs from M. subaraji by tympanum distinct (vs. hidden); dorsum orange-brown with black spots in life (vs. greyish brown); upper eyelid width equals one-third of interorbital distance UEW / IOS = 0.3 (vs. UEW / IOS = 0.7); internarial distance equals half of interorbital distance INS / IOS = 0.5 (vs. INS / IOS = 0.8).
Micryletta thongphaphumensis sp. nov. differs from M. menlanops by tibiotarsal articulation adpressed limb reaching level of tympanum (vs. reaching eye); supratympanic fold absent (vs. present); webbing between fingers and toes absent (vs. toe webbing rudimentary between toes II – III and III – IV); dorsum orange-brown with large black spots in life (vs. dorsal pale dark brown with small reddish speckles); dorsal surfaces of limbs orange-brown with brown marbling patterns (vs. dark brown with orange-red speckles); fifth toe longer than second toe, relative toes lengths: I <II <V <III <IV (vs. fifth toe shorter than second toe, relative toe lengths: I <V <II <III <IV); white patches on lips (vs. absent); iris bicoloured, with upper third bronze and lower two-thirds brownish black (vs. iris uniform black).
Micryletta thongphaphumensis sp. nov. differs from M. nigromaculata by tibiotarsal articulation adpressed limb reaching level of tympanum (vs. reaching eye); supratympanic fold absent (vs. present); dorsum light brown to orange-brown with large black spots (vs. dorsum with dark-brown irregular hourglass-shaped pattern edged with orange); white patches on lips (vs. absent); lateral sides of dorsum with brownish black stripes from snout to groin (vs. a large black blotch in inguinal area on each side).
Micryletta thongphaphumensis sp. nov. differs from M. lineata by second finger longer than fourth finger, relative finger lengths: I <II <IV <III (vs. second finger equal to fourth finger, relative finger lengths: I <IV = II <III); fifth toe longer than third toe, relative toes lengths: I <II <V <III <IV (vs. fifth toe equal to third toe, relative toes lengths: I <II <V = III <IV); ventral side of body smooth (vs. chest and abdomen with large flat abutting tubercles); tympanum diameter about one-third that diameter of eye (vs. about two-thirds).
description: Published as part of Cao, Yu-Yang, Suwannapoom, Chatmongkon, Kasyoka Kilunda, Felista, Gao, Wei, Wu, Chun-Lian, Wu, Yun-He & Che, Jing, 2024, Taxonomic revision of the genus Micryletta (Amphibia, Microhylidae), with description of a new species from Thailand, pp. 1361-1373 in Zoosystematics and Evolution 100 (4) on pages 1361-1373, DOI: 10.3897/zse.100.129398