Hyla annectans ( Jerdon, 1870 )

Raj, Prudhvi, Vasudevan, Karthikeyan, Dutta, Sushil Kumar, Sahoo, Gunanidhi, Mahapatra, Susmita & Sharma, Richa, 2023, Larval morphology of selected anuran species from India, Alytes 39 - 40, pp. 1-140 : 48-53

S11. Hyla annectans ( Jerdon, 1870) ( fig. 24‒25 )

Larval series examined. WT 133.5611( Mawblang , Cheerapunji, Meghalaya, India; 25.35453 N, 91.74230 E). Tadpoles were collected in a large perennial pond of one foot deep. The location of the pond was on a hill plateau at an elevation of more than 1000 m.a.s.l. The substratum in the pond was sandy .

Notes. Taxonomic identity of tadpoles was confirmed by partial sequence of 16S rRNA (OQ079503) generated from the tadpole voucher that showed no sequence divergence compared to the published Genbank sequence ( JQ 621934 ) from taxonomically identified specimens of Hyla annectans . External morphological descriptions for tadpoles of this species were given by Liu (1950), Ao & Khare (1986), Fei et al. (1999), Ao & Bordoloi (2001) and Fei & Ye (2003). The current external morphological description goes along with these earlier descriptions.

External morphology. Description of a tadpole at Gosner stage 37. Body elliptical and globular in dorsal and lateral perspectives ( fig. 24a‒b ). Body length 41 % of total length; maximum body diameter at the centre of body. Snout rounded in dorsal and lateral perspectives. Eyes large; located near lateral and oriented laterally; distance between eye and nostril 45.5 % of distance between eye and snout. Nostril opening rounded, closer to eyes than to snout; widely spaced in dorsal view; inter-narial distance is 51.8 % of inter-orbital distance, distance between nostril and snout 15.7 % of body length. Spiracle sinistral and moderate in length; inner wall of the tube formed but attached to body wall; tube opening located and above the lateral side of venter. Distance between spiracle and snout 65.7 % of body length. Opening of vent tube medial. Tail tip acutely rounded; musculature tallest at body tail junction and musculature linear till mid-length of tail, tapering beyond. Dorsal fin originating anterior to junction between body tail, ventral fin originating at ventral terminus; dorsal and ventral fins of equal heights and ovate; maximum height of caudal fin at mid length. Height of tail muscle 1.46 times width of tail muscle at body-tail junction. Tail (caudal) musculature accounting for 34.9 % of height of tail. Lateral line visible. Glands absent on outer integument.

Oral disc nearly ventral in location ( fig. 24c ). Rostral width of oral disc 41.7 % of maximum body width, not emarginated, not visible dorsally; single row of marginal papillae spread on margin of lower labium and two-thirds of lateral sides of upper labium; 10‒15 submarginal papillae at lateral commissures; both labia of equal size. Labial tooth row formula A2(2)/P3(1). Order of lengths of labial tooth rows A1> P1> P2> A2> P3. Jaw sheaths well developed and keratinized delicately. Both jaw sheath margins with small uniform serrations; supra-rostrodont with broad median region and thin convex extended lateral process; infra-rostrodont U-shaped, convex laterally and concave medially.

Measurements of the 56 tadpoles at various Gosner stages (25‒28, 30‒41) are given in tab. 11 .

Coloration. In life, dorsal body olive; inner and outer integuments spotted with tiny melanophores. In lateral perspective, flanks comparatively darker than dorsum. Ventral integument transparent with dark gut coils visible; neck speckled with melanophores. Both fins transparent and spotted with numerous tiny melanophores uniformly spread and with few large blotches along margins of fins. Caudal fin musculature dirty yellow and spotted with tiny melanophores. Spiracle, oral disc and vent tube translucent; oral disc dotted with few melanophores.

Buccopharyngeal morphology. Buccal roof ( fig. 25a‒b ). Prenarial arena of roof with no pustules. Internal nares transverse; oriented medially; gap between nares narrow, about half the length of each nare; anterior narial wall smooth with few pustules towards medial and no papillae; posterior wall smooth and valvular with a tiny narial valve projection near medial. Postnarial arena with two pairs of papillae situated midway between posterior narial wall and median ridge; papillae arranged in an inverted ‘V’; anterior papillae shorter, and posterior papillae longer; surface of papillae rugose. Median ridge papilla broad flap with a rugose margin and a broad flattened tip. Moderately elongated broad bifid lateral ridge papillae with rugose margin perpendicular to median ridge. BRA well defined with five pairs of long conical pustulated papillae present along lateral border of the roof; some BRA papillae bifid; about 20 tiny pustules spread across BRA. Glandular zone wide and prominent; secretory pits spread medially. Dorsal velum margin smooth and discontinuous.

Buccal floor ( fig. 25c‒d ). Prelingual arena with a pair of short dilated palps located along posterolateral corners on each side of jaw sheath; palps margin rugose with many tiny projections. Tongue anlage broad; pair of short conical lingual papillae located medially and pointing outwards. BFA well defined by four pairs of BFA papillae; papillae beginning anteromedial to buccal pocket continue along posterolateral commissure of BFA; papillae short, broad, rugose and of unequal size; few papillae branched; BFA smooth with about 15–20 pustules; space between tongue anlage and buccal pockets with about eight pustules. Buccal pockets wide and transversely arranged; a pair of pre-pocket papillae present. Region behind BFA and margin of ventral velum broad and smooth; few papillae present between BFA and margin of velum. Ventral velum wide and sinuate. Ventral velum margin smooth with five to six projections on each side; three outer projections large and widely spaced; two to three closely spaced medial projections; median notch prominent and deep. Glottis exposed posterior to ventral velum.

Denticles ( fig. 25e ) closely packed and moderately curved towards mouth at apex. Oral angle obtuse; sheath and body of equal width; head broad and curved with 10‒12 short and moderately rounded cusps.

Each serration ( fig. 25f ) on jaw sheath with a wide base and a broad rounded head.

Figures

Figure 24. Hyla annectans, Gosner stage 37. External morphology: (a) Lateral view, (b) Dorsal view, (c) Ventral view. Scale = 10 mm.

Figure 25. Hyla annectans, Gosner stage 37. Buccopharyngeal and denticles: (a) Buccal roof, Scanning Electron Microscopy photograph, scale = 0.2 mm, (b) Buccal roof, Alcian Blue stained photograph, ventral view, scale = 1 mm, (c) Buccal floor, Scanning Electron Microscopy photograph, scale = 0.2 mm, (d) Buccal floor, Alcian Blue stained photograph, ventral view, scale = 0.5 mm, (e) Individual denticles, (f) Jaw sheath serrations.