Nyctibatrachus pulivijayani, Sonali Garg, Robin Suyesh, Sandeep Sukesan & Sd Biju, 2017

Sonali Garg, Robin Suyesh, Sandeep Sukesan & Sd Biju, 2017, Seven new species of Night Frogs (Anura, Nyctibatrachidae) from the Western Ghats Biodiversity Hotspot of India, with remarkably high diversity of diminutive forms, PeerJ 5 (3007), pp. 1-50 : 18-22

Nyctibatrachus pulivijayani sp. nov.

urn:lsid:zoobank.org:act:E4F167C1-8340-4779-8CEF-622AC7AB350C

Vijayan’s Night Frog

( Figs. 1 and 5 ; Tables S1–S7)

Holotype. ZSI/WGRC/V/A/902, adult male, from Pandipath (08°40 42.0 N 77°11 38.6 E, 1,250 m), Thiruvananthapuram district, Kerala state, India, collected by SDB, SG and Vijayan on 19 June 2016.

Paratypes. ZSI/WGRC/V/A/903–905, three adult males collected along with the holotype, and ZSI/WGRC/V/A/906, adult male, collected from the same locality as holotype, by SDB and SG on 29 June 2015.

Etymology. This species is named after Mr. Vijayan Kani for consistently offering tremendous field support over two decades to SDB and his students during studies in the Western Ghats. Vijayan, a tribal from Agasthyamala hills of Kerala, acquired the name ‘Pulivijayan’ after he braved a leopard’s attack. The name is derived from two words–‘puli’ meaning leopard in Malayalam (official language of Kerala state) and ‘vijayan’. The species epithet ‘ pulivijayani ’ is used as a noun in the genitive case. The specific word ‘puli’ also refers to leopard-like spots observed on the dorsal surface of this species.

Diagnosis. Nyctibatrachus pulivijayani can be distinguished from known congeners by the following combination of morphological characters: (1) miniature-sized adult males (SVL 13.3–14.9 mm, N = 5); (2) head width nearly equal to head length (male HW/HL ratio 98.3–102%, N = 5); (3) presence of weakly developed dorsolateral glandular folds separated by scattered granular projections; (4) dorsum light brown to silvery-brown with prominent dark brown spots in life; (5) third finger disc slightly wider than finger width (male FDIII 0.3–0.4, FWIII 0.2–0.3, N = 5), with dorso-terminal groove and cover bifurcate distally; (6) fourth toe disc slightly wider than toe width (male TDIV 0.4–0.5, TWIV 0.2–0.3, N = 5), with dorso-terminal groove and cover bifurcate distally; (7) presence of single palmar tubercle; (8) foot webbing absent; (9) thigh nearly equal to shank length (male TL/SHL ratio 94–104.5%, N = 5); and (10) thigh nearly equal to foot length (male TL/FOL ratio 95.5–106%, N = 5).

Morphological comparison. Nyctibatrachus pulivijayani can be distinguished from all its congeners, expect N. anamallaiensis , N. athirappillyensis sp. nov., N. beddomii , N. deccanensis , N. kempholeyensis , N. manalari sp. nov., N. minimus , N. minor , N. robinmoorei sp. nov., N. sabarimalai sp. nov. and N. webilla sp. nov. by its smaller snoutvent size, male SVL 13.3–14.9 mm (vs. larger, male SVL 18.1–76.9 mm), dorsal skin not prominently wrinkled and/or granular (vs. prominently wrinkled and/or granular), and absence of webbing between toes (vs. present); differs from N. athirappillyensis , N. deccanensis and N. kempholeyensis by absence of webbing between toes (vs. present); differs from N. minor by its dorsal skin without distinct dorsolateral glandular folds separated by an ‘X’ pattern on anterior half of back (vs. present); and differs from N. webilla by its third finger disc with dorso-terminal groove and cover bifurcate distally (vs. third finger without dorso-terminal groove).

Because of the comparable snout-vent size, Nyctibatrachus pulivijayani could be confused with three previously known species N. anamallaiensis , N. beddomii and N. minimus , and three new species N. manalari , N. robinmoorei and N. sabarimalai . However, N. pulivijayani differs from N. anamallaiensis by its dorsum light brown to silvery-brown with prominent dark brown spots in life (vs. dorsum dark greyish or reddish-brown without prominent dark spots), head width nearly equal to head length, male HW/HL ratio 98.3–102%, N = 5 (vs. head wider than long, male HW/HL ratio 115.7–126.1%, N = 5), relatively larger male SL/HL ratio of 37.9–48.1%, N = 5 (vs. male SL/HL ratio of 29.4–34.9%, N = 5) and eye length shorter than snout length, male EL/SL ratio 68–78.3%, N = 5 (vs. longer, male EL/SL ratio 125–140%, N = 5).

Nyctibatrachus pulivijayani differs from N. beddomii by its dorsolateral glandular folds separated by scattered granular projections (vs. dorsal skin finely granular), head width nearly equal to head length, male HW/HL ratio 98.3–102%, N = 5 (vs. head wider than long, male HW/HL ratio 106.6–129.3%, N = 10), and forearm shorter than hand length, male FAL/HAL ratio 71.4–84.8%, N = 5 (vs. nearly equal, male FAL/HAL ratio 93.3–103.7%, N = 10).

Nyctibatrachus pulivijayani differs from N. minimus by its dorsolateral glandular folds separated by scattered granular projections (vs. dorsal skin having faint and interrupted glandular folds).

Nyctibatrachus pulivijayani differs from N. robinmoorei by its dorsum light brown to silvery-brown with prominent dark brown spots in life (vs. dorsum greyish or orangishbrown without prominent dark spots), forearm shorter than hand length, male FAL/HAL ratio 71.4–84.8%, N = 5 (vs. longer, male FAL/HAL ratio 105.3–111.8%, N = 2), thigh nearly equal to shank, male TL/SHL ratio 94–104.5%, N = 5 (vs. longer, male TL/SHL ratio 127.5–130.8%, N = 2), and thigh nearly equal to foot, male TL/FOL ratio 95.5–106%, N = 5 (vs. longer, male TL/FOL ratio 122.6–130.8%, N = 2).

Nyctibatrachus pulivijayani differs from N. sabarimalai by its dorsal coloration light brown to silvery-brown with prominent dark brown spots in life (vs. light greyish-brown dorsum without dark brown spots), relatively larger snout-vent size, male SVL 13.3–14.9 mm, N = 5 (vs. male SVL 12.3–13.2 mm, N = 5), head width nearly equal to head length, male HW/HL ratio 98.3–102%, N = 5 (vs. head longer than wide, male HW/HL ratio 82.4–89.8%, N = 5), and relatively smaller male FAL/HAL ratio of 71.4–84.8%, N = 5 (vs. male FAL/HAL ratio of 85.7–96.6%, N = 5).

For differences with Nyctibatrachus manalari see comparison of that species.

Description of holotype (measurements in mm). Adult male (SVL 13.3); head small, length subequal to its width (HW 5.1, HL 5.0); snout rounded in dorsal and lateral view, its length (SL 2.1) longer than horizontal diameter of eye (EL 1.6); loreal region acute with indistinct canthus rostralis; interorbital space flat, wider (IUE 1.9) than upper eyelid (UEW 0.7) and internarial distance (IN 1.5); nostril closer to eye (EN 0.7) than the tip of snout (NS 0.9); tympanum indistinct; vomerine ridge present, bearing small teeth, at an angle of 75° to the body axis, closer to each other than choanae, shorter than the distance between them; tongue emarginated, bearing no median lingual process. Forearm (FAL 2.3) shorter than hand length (HAL 3.0), finger length formula: I <II <IV <III, finger discs slightly wider compared to its width (FDI 0.3, FWI 0.2; FDII 0.3, FWII 0.2; FDIII 0.3, FWIII 0.2; FDIV 0.3, FWIV 0.2), finger disc with dorso-terminal groove, cover bifurcate distally; subarticular tubercles prominent, oval, single, all present; prepollex distinct, oval; single palmar tubercle, oval, distinct; nuptial pads present, weakly developed. Thigh length (TL 6.3) shorter than shank (SHL 6.5) and foot (FOL 6.5), relative digit lengths I <II <V <III <IV, toe discs slightly wider compared to toe width (TDI 0.2, TWI 0.1; TDII 0.3, TWII 0.2; TDIII 0.4, TWIII 0.2; TDIV 0.4, TWIV 0.2; TDV 0.4, TWV 0.2), toe discs with dorso-terminal groove, cover bifurcate distally; foot webbing absent; subarticular tubercles well developed, oval, single, all present; inner metatarsal tubercle present, oval; outer metatarsal tubercle weakly developed.

Skin of snout shagreened to sparsely granular, upper eyelids with a few prominent glandular warts especially on the margins, presence of weakly developed dorsolateral glandular folds separated by scattered granular projections; sides of the head, anterior and posterior parts of back and upper and lower parts of flank shagreened with scattered glandular projections; subocular gland indistinct; upper surface of arms and legs shagreened with weakly developed granular projections; ventral surfaces smooth; a pair of prominent femoral glands present on the ventral surface of thighs.

Colour of holotype. In life. Dorsum silvery-brown with prominent brown spots, snout lighter in colour, a dark brown stripe between the eyes demarcating a triangular cream colour patch on the snout ( Fig. 5 C); upper and lower parts of flank lighter in colour than the dorsum and with scattered minute black spots and larger white spots; forelimbs (including fingers) and hind limbs (including toes) light silvery-brown with dark brown transverse bands and scattered white spots ( Figs. 5 A and 5C). Ventral surfaces light yellowish-brown with minute black speckles, hand and foot darker in colour, throat light grey ( Fig. 5 F). In preservation. Dorsum light grey with prominent dark grey spots, lateral sides of head grey with minute black spots, upper eyelids grey ( Fig. 5 I); forelimbs (including fingers) and hind limbs (including toes) grey with dark grey transverse bands; anterior and posterior parts of flanks grey. Ventral surfaces light greyish-white with minute dark grey speckles, hand and foot dark grey.

Variations. Morphometric data from five adult males, including the holotype, is given in Table S6. Overall, the colour, markings and meristic characters of the paratypes (except ZSI/WGRC/V/A/904) are similar to the holotype. Colour in preservation. ZSI/WGRC/V/A/904: dorsum dark grey with less conspicuous dark grey spots, ventral surface with more prominent dark grey speckles. ZSI/WGRC/V/A/906: dorsum light grey with fewer dark grey spots, ventral surface with more prominent dark grey speckles. Secondary sexual characters. Male (ZSI/WGRC/V/A/902), femoral glands present ( Figs. 5 G and 5H), nuptial pads weakly developed.

Distribution and natural history. Nyctibatrachus pulivijayani is currently known only from its type locality, which is located in Agasthyamala Hills, south of Palghat gap in the Western Ghats state of Kerala. Animals were found hiding under herbs and grasses on marshy ground (usually away from water) inside an evergreen forest. Males were observed calling during the day (around 11:00 h) and in the late evening (18:00 h).

Figures

Figure 1 Morphometric differentiation of species using the discriminant function analyses. (A) Projection on factor plane first and second explaining 79.1 % of the variations among seven miniature-sized species. (B) Projection on factor plane first and second explaining 83.9 % of the variations among five medium-sized species. (C) Projection on factor plane first and second explaining 86.3 % of the variations among six large-sized species.

Figure 5 Holotype of Nyctibatrachus pulivijayani sp. nov. (ZSI / WGRC / V / A / 902). (A) Dorsolateral view, in life. (B) Size (SVL 13.3 mm) in comparison to the Indian five-rupee coin (24 mm diameter). (C) Dorsal view, in life. (D) Dorsal surface third finger disc, in preservation. (E) Dorsal surface of fourth toe disc, in preservation. (F) Ventral view, in life. (G) Femoral glands, in preservation. (H) Close-up of femoral glands after removal of skin showing multiple glands. (I) Lateral view of head, in preservation. (J) Ventral view of hand, in preservation. (K) Ventral view of foot, in preservation. (L) Schematic illustration of foot webbing.