Euphlyctis jaladhara, Dinesh & Channakeshavamurthy & Deepak & Shabnam & Ghosh & Deuti, 2022

Dinesh, K. P., Channakeshavamurthy, B. H., Deepak, P., Shabnam, A., Ghosh, Avrajjal & Deuti, Kaushik, 2022, Discovery of a new species of Euphlyctis (Anura: Dicroglossidae) from the western coastal plains of peninsular India, Zootaxa 5100 (3), pp. 419-434 : 422-425

Euphlyctis jaladhara sp. nov.

Holotype: ZSI / WGRC/2948 , an adult male ( SVL 37.8 mm) collected by BH Channakeshavamurthy and team in October 2017 from the surroundings of Thattekad Bird Sanctuary (N 10.1272; E 76.6840), Kerala, India.

Paratypes: ZSI / WGRC/2889 , an adult female ( SVL 47.3 mm) and ZSI / WGRC/2946 , an adult female ( SVL 62.1 mm), collection details same as holotype .

Lineage diagnosis: Euphlyctis jaladhara sp. nov. is diagnosed phylogenetically as a member of the larger ‘ Euphlyctis clade’ ( Fig. 2 ). The new species shows a possible sister relationship to the clade comprising E. ehrenbergii with a genetic distance of 6.4% and E. kalasgramensis with a genetic divergence of 5.4% for the mt 16S rRNA gene ( Fig. 2 ). Under field conditions, E. cyanophlyctis could be a syntopic congener in the peripheral zone of its range of distribution. For the mt 16S rRNA gene, Euphlyctis jaladhara sp. nov. exhibits a genetic divergence of 4.4% with E. cyanophlyctis . For the nuclear Tyrosinase gene, Euphlyctis jaladhara sp. nov. ( AB 489017.1) shows a genetic divergence of 0.9% with E. cyanophlyctis ( MT 782272.1).

Field Diagnosis: Under field conditions among the skittering frogs, Euphlyctis jaladhara sp. nov. is sympatric with P. kerala and P. karaavali in the south of Palghat gap. In the north of the Palghat gap, the new species is sympatric with P. aloysii and P. karaavali . The new species could be sympatric with E. cyanophlyctis ( Fig. 6 ) in the Western Ghats region of Madikeri (based on the two sequences of Euphlyctis jaladhara sp. nov. included in the studies of Kurabayashi et al. 2005 and Hasan et al. 2014 labeled as E. cyanophlyctis ). Other than E. cyanophlyctis , no sympatric congeneric species could be encountered in field conditions. Additionally, Euphlyctis jaladhara sp. nov. can be easily distinguished from the rest of the skittering frogs by a combination of morphological characters like male adult size small ( SVL, 33.7 mm to 37.8 mm) and large females ( SVL, 47.3 mm to 62.1 mm); head length equal to head width; acutely pointed snout; snout equal to eye diameter; angled canthus rostralis with flat loreal region; inter-orbital distance half of the upper lid width; distinct tympanum equal to eye diameter; first finger longer than the second finger; pre-pollex tubercle and supernumerary tubercles absent in hand; tibio-tarsal articulation reaches nostril; porous warts absent; distinct black line from the back of the shoulder to groin separating the dark dorsal colour and ventral white colour; ventral side of males white and females spotted; back of the thigh with a single white band (see morphological characters key to members of Euphlyctis below).

Geography: The species is known from freshwater bodies of the western coastal plains of peninsular India.

Description of Holotype (ZSI/WGRC/2948) ( Fig. 2 , Fig. 3 , Fig. 4 )

A small sized skittering frog (SVL = 37.8 mm) with lean, elongated, and squat body; head width subequal to head length (HW = 14.3 mm; HL = 13.9 mm); snout acutely pointed (SL = 4.0 mm) and subequal to eye diameter (EL = 4.7 mm); canthus rostralis angled, loreal region flat, inter-orbital space flat (IUE = 1.4 mm) half of the upper lid (UEW = 2.9 mm) and subequal to internarial distance (IN = 1.1 mm); distance between the back of eyes 1.7 times more than front of eyes (IFE = 5.2 mm; IBE = 9.2 mm); nostrils oval, on the lateral sides and nearer to the tip of snout; symphysial knob moderate; tympanum distinct, visible below the supratympanic fold (TYD = 3.6 mm) and close to the eye (TE = 0.4 mm); vomerine ridges present, weak; tongue bifid without a papilla.

Forearm robust and short (FLL = 7.5 mm), slightly shorter than the hand (HAL = 9.0 mm); fingers thin without any dermal fringes, first finger (FL1 = 3.3 mm) longer than the second finger (FL2 = 2.7 mm) and shorter than the third finger (TFL = 4.4 mm), tips blunt without any enlarged discs, webbing between fingers absent; subarticular tubercles moderate, rounded and pre-pollex tubercle and supernumerary tubercles absent.

Hind limbs long, touch each other when folded at right angles to the body, and tibio-tarsal articulation reaches nostril; femur length subequal to tibia length (FL = 20.9 mm; TiL = 19.4 mm); foot length is 1.9 times tarsus length (FOL = 19.7 mm, TaL = 9.9 mm), relative toe length I<II<III<V<IV (FTL = 11.7 mm); inner toe minute (ITL = 3.5 mm), webbing complete, no phalanges free on toes; inner metatarsal tubercle (IMT = 2.0 mm) distinct, outer metatarsal tubercle, supernumerary tubercles and tarsal tubercle absent.

In preservative ( Fig. 4 ), overall skin on the dorsum smooth uniform with few minute projected granular spots, but concentrated at the region of the vent; ventrally smooth on throat, belly, hands, and back of thighs. Porous warts absent. Colour on the dorsum dark, stone black mottled patches on the light grey background; limbs not barred but thighs faintly barred. On the lateral sides, a distinct black line from the back of the shoulder to the groin separates the dark dorsal colour from the ventral white colour. Ventrally, throat, belly, forehand, thighs, tibia, and tarsus uniform cream white, hand and foot light grey. Back of thigh with a single white band.

In life ( Fig. 3 ), dorsal upper surface of the forearm, hand, thigh, tibia, tarsus, and entire dorsum light cream background with olive green irregular blotched pattern. Lateral sides of the body with a distinct black line from the back of shoulders to the groin separating the upper dark colour from the ventral light colour. Eye diamond-shaped, pupil black, iris golden brown ( Fig. 3 ).

Secondary sexual characters and sexual dimorphism ( Fig. 4 ): Adult males have a pair of dark black external vocal sacs at the lateral sides of the throat ( Fig. 4 ), but the nuptial pads are absent on the first finger. In general, females have grey spots on the entire ventral region (as compared to the white ventral side of the males) ( Fig. 4 ).

Additional information from paratypes (and other reference collections) and variations: Morphological data are given in Table 1 . Paratypes range from 47.3 mm to 62.1 mm in SVL; all the males in the collections ranged from 33.7 mm to 37.8 mm in SVL, and females ranged from 40.8 mm to 62.1 mm in SVL. The external morphological characters of holotype and paratypes were similar to the reference collections except for the colour characters for sexual dimorphism ( Fig. 5 ) .

Etymology: The new species epithet is derived from the Sanskrit word Jaladhârâ (jala=water + adhâra = reservoir), meaning ‘deposit of water’. The new species is treated as a symbol of freshwater resources, as this frog is seen floating on the surface of freshwater ponds / streams during both day and night time. The species epithet is treated as a noun in apposition to the generic name. Suggested common name: ‘Jaladhara skittering frog’.

Distribution and Natural history: Euphlyctis jaladhara sp. nov. is known specifically from Thattekad, Kochi, and Mangalore (Konaje, Padil) based on the genetic sequences. Our field studies suggest the presence of the species throughout the western coastal plains (Kerala coastal plain, Karnataka coastal plain, and Konkan coastal plain) all along the foothills of the Western Ghats from Thattekad to Daman Ganga River side, Khanvel, Nagar Haveli, and Diu Union Territories of India. Looking at the distribution range, it appears that the species could be present in any freshwater bodies from Kanyakumari to Diu Union Territories of India. Although the species is well documented in the western coastal plains of peninsular India, its elevational preference all along the westerly slopes of the Western Ghats needs to be assessed with additional field explorations.

In earlier studies, the two sequences AB167938.1 ( Kurabayashi et al. 2005) and AB530596.1 ( Hasan et al. 2014) labeled as E. cyanophlyctis are similar to the sequences of Euphlyctis jaladhara sp. nov., generated in this study. Those two sequences along with the new sequences generated in this study formed a clade which indicates the possibilities of the new species in sympatry with E. cyanophlyctis in the periphery of their range of distribution.

Figures

FIGURE 2. Maximum Likelihood (ML) tree for species of Euphlyctis and Phrynoderma based on a concatenated dataset of 575 bp of mitochondrial 16S rRNA gene and 699 bp of nuclear Tyrosinase gene.

FIGURE 3. A) Male and B) Female of Euphlyctis jaladhara sp. nov. in life.

FIGURE 4. Holotype of Euphlyctis jaladhara sp. nov. A) dorsal view; B) ventral view (ZSI/WGRC/A/2948).

FIGURE 5. Type series of Euphlyctis jaladhara sp. nov. dorsal and ventral view, A) (holotype, ZSI/WGRC/A/2948 (male); B) paratype ZSI/WGRC/A/2946 (female); C) paratype ZSI/WGRC/A/2889) (female).

FIGURE 6. Sympatric congeners in the field (only in the overlapping zones, at the periphery of their range of distribution) A) Euphlyctis cyanophlyctis (photograph from Tumkur, Deccan plateau) and B) Euphlyctis jaladhara sp. nov. from the surroundings of the Thattekad, Bird Sanctuary.