Zhangixalus jodiae, Nguyen & Ninh & Orlov & Nguyen & Ziegler, 2020

Nguyen, Tao Thien, Ninh, Hoa Thi, Orlov, Nikolai, Nguyen, Truong Quang & Ziegler, Thomas, 2020, A new species of the genus Zhangixalus (Amphibia: Rhacophoridae) from Vietnam, Journal of Natural History 54 (1 - 4), pp. 257-273 : 262-270

publication ID	https://doi.org/ 10.1080/00222933.2020.1754484
persistent identifier	https://treatment.plazi.org/id/B367C51A-DB37-B961-6A93-FE1BFBF8FF2F
treatment provided by	Carolina
scientific name	Zhangixalus jodiae
status	sp. nov.

Treatment

Zhangixalus jodiae sp. nov. ( Figure 2 View Figure 2 )

Holotype. VNMN 07121 View Materials , adult male, collected by Tao Thien Nguyen, at 19:00 h on 24 March 2018, in the forest near Tung Vai Commune , Quan Ba District, Ha Giang Province, northern Vietnam (20°47 ʹ 56 ʹ ’ N, 106°59 ʹ 52 ʹ ’ E, at an elevation of ca. 1245 m a.s.l.)

Paratypes. VNMN 07120 View Materials , VNMN 07122 – 07128 View Materials , eight adult males, the same collection data as the holotype, collected between 24 and 26 March 2018 at elevations between 1180 and 1320 m a .s .l. For measurements of the type series see Table 3.

Diagnosis. The new species is distinguished from its congeners and other small rhacophorid species by a combination of the following characters: (1) Size small (SVL 36.1 – 39.8 mm in males); (2) head as long as wide; (3) vomerine teeth present; (4) snout round; (5) dorsal skin smooth; (6) dermal appendage at vent absent; (7) hand-webbing formula I1-1II1-1III2-1IV and toe webbing formula I1-1II½-1III0-1½IV1-½V; (8) dorsal surface of head and body green without spots; (9) axilla cream with large black blotches, groin, anterior and posterior thighs and ventral surface of tibia black with orange blotches; and (10) lower jaw region greyish, chest and belly cream.

Description of holotype. Size small, body robust (SVL 36.1 mm); head moderately compressed, as long as wide (HL 14.8 mm, HW 14.7 mm), slightly convex above; snout round anteriorly, slightly protruding beyond lower jaw in lateral view, longer than horizontal diameter of eye (SNL 6.5 mm, ED 4.8 mm); canthus rostralis round, loreal region oblique, concave; interorbital distance wider than internarial distance and upper eyelid (IOD 5.7 mm, IN 4.3 mm, UEW 3.8 mm); distance between anterior corners of eyes about 67% of distance between posterior corners of eyes; nostril round, without lateral flap of skin, closer to the tip of snout than to eye; pupil oval, horizontal; tympanum distinct, round, about half of eye diameter, about twice greater than the distance between tympanum and eye; pineal ocellus absent; spinules on upper eyelid absent; vomerine teeth well developed, in two oblique ridges; choanae rounded; tongue deeply notched posteriorly; supratympanic fold distinct, extending from behind eye to beyond level of axilla.

Forelimbs. Upper arm short, about one-third of forearm length (UAL 6.2 mm, FAL 18.7 mm), dermal fringe along the outer edge of forearm present, not well developed; relative lengths of fingers I<II<V<III; tips of fingers with enlarged discs with distinct

(Continued) circum-marginal grooves; disc of finger III approximately two times of the width of finger III (fd3/fw3 1.72), smaller than tympanum diameter (fd3/TYD 0.88); webbing formula I1- 1II1-1III2-1IV, subarticular tubercles distinct, blunt, round, formula 1, 1, 2, 2; nuptial pads prominent, oval, smooth.

Hindlimbs. Heels overlapping when held at right angles to the body; tibia length about three times greater than tibia width (TbL 17.3 mm, TbW 5.1 mm), slightly longer than thigh length (FeL 17.1 mm), shorter than foot length (FoL 24.9 mm); relative lengths of toes I<II<III<V<IV; tips of toes with enlarged discs with distinct circum-marginal grooves, discs slightly smaller than those of fingers; webbing formula I1-1II½-1III0-1½IV1-½V; subarticular tubercles distinct, blunt, round, formula 1, 1, 2, 3, 2; inner metatarsal tubercle small (IMT 2.07 mm); dermal ridge along the outer edge of tibia and tarsus present; dermal projection at tibiotarsal articulation present.

Skin texture. Dorsal surface of head and body smooth; dorsolateral folds absent; throat and chest smooth, belly granular; ventral surface of fore and hind limbs granular; dermal appendage above vent absent.

Colouration in life. Iris silver, pupil horizontal, black; dorsal surface of the head and body green without spots; tympanum and supratympanic region green; dorsal surface of forelimbs and hindlimbs green; flanks cream, axilla and groin with large black blotches; anterior and posterior parts of thigh, and ventral surface of tibia black with orange blotches; ventral surface of arm and thigh cream; lower jaw and throat region greyish, chest and belly cream; supracloacal area white; dermal fringes on outer edges of fore and hind limbs white; ventral side of webbing orange in hindlimbs and cream in forelimbs, nuptial pads yellow.

Colouration in preservative. As in life, but with green fading to grey and pale orange fading to white.

Male secondary sexual characters. Nuptial pad present; external single subgular vocal sac, throat greyish.

Advertisement call. Call descriptions are based on two advertisement calls of one paratype (VNMN 07126). Advertisement calls were recorded at 17.3°C ambient temperature. Each call was 1.1 s in duration and consisted of six notes, each ~6 ms in duration and uniformly spaced ~15 ms. The two notes were 8.8 s apart ( Figure 3 View Figure 3 ). The dominant frequency was uniformly 2.0 kHz, with harmonics at 3.7 and 5.5 kHz. Calls were amplitude modulated, with the last note of each call of lower amplitude than the others. Three calls of a more distant frog were also detected in the recording, each with six notes, and consistent with those described above.

Comparison

Based on our molecular data, Zhangixalus jodiae sp. nov. is closely related to Z. nigropunctatus , Z. yaoshanensis , Z. pinglongensis , and Z. chenfui . The genetic distance between Zhangixalus jodiae sp. nov. and the latter is approximately 3.6%, which is indicative of species-level divergence in anurans ( Vences et al. 2005). Morphologically, these species are similar to each other in the following characters:small size in males SVL 32.0 – 37.0 mm in Z. nigropunctatus (Liu et al. 1962) , 32 – 38.5 mm in Z. pinglongensis ( Mo et al. 2016) , and 31.6 – 36.4 mm in Z. yaoshanensis ( Chen et al. 2018) ; dorsum green, smooth, without spots; webbing moderately developed; dermal flap on heel and supracloacal dermal ridge absent.

However, Zhangixalus jodiae sp. nov. differs from Z. nigropunctatus (Liu et al. 1962) by colouration on flank and thigh (cream with irregular black and orange blotches vs. flank and thigh cream with black blotches in Z. nigropunctatus ); from Z. pinglongensis by colouration on flank and thigh (large black blotches in the axilla, black and orange blotches in the groin, thigh and ventral side of the tibia vs. irregular white blotches interposed by black from axilla to flank and thigh), ventral aspect of feet and webbing (cream vs. tangerine); from Z. yaoshanensis ( Chen et al. 2018) by having different flank colour pattern (irregular black and orange blotches vs. cream with small greyish spots), the colouration on the thigh (irregular black blotches interposed by orange vs orange-red without spots); from Z. chenfui by the absence of a white line isolating the dorsal part from the ventral part ( Liu 1945).

The new species differs from other green rhacophorid tree frogs recorded from Vietnam and the neighbouring countries as follows: Zhangixalus jodiae sp. nov. can be distinguished from Z. duboisi , Z. omeimontis , Z. burmanus , Z. dennysi , Z. pachyproctus , and Z. feae by having a smaller size (SVL<60 mm vs. SVL> 60 mm). The new species differs from the other tree frogs in the same size by colour pattern: dorsal surface of head and body green without spots and axilla cream with large black blotches, groin, anterior and posterior part of thighs and ventral surface of tibia black with orange blotches vs. axilla and groin yellowish with small grey spots in Z. zhoukaiyae ( Pan et al. 2017) ; axilla and groin yellow with black dots in Z. dorsorviridis ( Bourret 1937) ; flanks as well as anterior and posterior part of thigh cream with scattered mottling in Z. minimus ( Rao et al. 2006) ; varies from dark yellowish brown to light green on dorsal and lateral surfaces, with numerous light-brown spots that have dark yellowish brown edges in Z. wui and Z. hongchibaensis ( Li et al. 2012) ; flank and front-rear of thigh cream without spot in Z. hungfuensis ( Liu and Hu, 1961) ; back green with round brown spot in Z. dugritei ( David, 1872) ; front and rear of thigh red-orange with dark spot with dorsal surface of foot green with dark spots in Z. moltrechti ( Fei et al. 2012) ; dorsum green with numerous dark spots in Z. arboreus ( Okada and Kawano, 1924) ; flank and groin cream without spot in Z. schlegelii ( Günther, 1858) .

The male advertisement calls of the most closely related species Z. chenfui , Z. nigropunctautus and Z. yaoshanensis are unknown. The male advertisement call of Zhangixalus jodiae sp. nov. differs from that of Z. pinglongensis by having six, singlepulsed notes of 1.1 s duration (versus two notes with six pulses, each ~ 0.4 s duration) per call ( Mo et al. 2016).

Distribution. Zhangixalus jodiae sp. nov. is currently known only from the type locality in Ha Giang Province, northeastern Vietnam ( Figure 4 View Figure 4 ).

Natural history. The specimens were found between 19:00 and 24:00 h on the ground, near streams. The surrounding habitat was undisturbed forest of large hardwoods, shrub and liane ( Figure 5 View Figure 5 ). The air temperature ranged from 17.0 – 21.4°C at night and the relative humidity was 88 – 92% at the site. The breeding biology, females and tadpoles of Zhangixalus jodiae sp. nov. are unknown.

Conservation status. Currently known only from the type locality in Cao Ma and Ta Van communes, Quan Ba District, Ha Giang Province, northeastern Vietnam . However, the actual distribution range of this species should be confirmed in further studies. Given the available information, we suggest this species be considered as Data Deficient following IUCN ’ s Red List categories ( IUCN 2016).

Etymology. The specific epithet is in honour of Dr. Jodi Rowley from the Australian Museum for her great contribution to amphibian taxonomy in Asia. We propose the following colloquial names: Jodi ’ s Treefrog (English) and Ếch cây jô-đi (Vietnamese).