Chirixalus simus ( Annandale, 1915 )

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 : 104-106

S25. Chirixalus simus ( Annandale, 1915) ( fig. 51‒52 )

Larval series examined. WT 100, W T121 (Kolkata, West Bengal, India). Tadpoles of this species were reared in North Orissa University from eggs collected from taxonomically identified adults of Chirixalus simus from Kolkata, West Bengal .

Notes. No descriptions of tadpoles of this species are available.

External morphology. Description of a tadpole at Gosner stage 37. Body ovoid and globular in dorsal and lateral perspectives ( fig. 51a‒b ). Body length 34.5 % of total length; maximum body diameter at centre of abdomen. Snout rounded in dorsal and lateral perspectives. Eyes large, located and oriented dorsolaterally; distance between eye and nostril 50 % of distance between eye and snout. Nostril opening spherical and depressed, closer to eye than to snout, placed parallel to eye in dorsal view; inter-narial distance 50 % of inter-orbital distance; distance between nostril and snout 13.4 % of body length. Spiracle sinistral with inner wall attached to body wall; tube oriented posterolateral, its opening located below the middle of the lateral side of venter. Distance between spiracle and snout 62.2 % of body length. Opening of vent tube dextral. Tail tip pointed; musculature linear on first third length of tail, tapering beyond. Dorsal fin originating anterior to body tail junction; ventral fin originating at ventral terminus; dorsal fin wider than ventral fin; maximum height of caudal fin at one-third of tail length. Height of tail muscle 1.23 times width of tail muscle at tail-body junction. Tail (caudal) musculature accounting for 55.1 % of height of tail. Dermal pores conspicuous. Glands absent on outer integument.

Oral disc anteroventral in location ( fig. 51c ). Rostral width of oral disc 35.8 % of maximum body width, emarginated, not visible dorsally; marginal papillae in single row at lateral commissures and double row on lower labium; marginal papillae broadly interrupted on upper labium and with a narrow gap on lower labium; four to five submarginal papillae at lateral commissures; both labia of equal size. Labial tooth row formula A3(2‒3)/P3(1). Order of lengths of labial tooth rows P1> P2> A2> A1> P3> A3. Jaw sheaths keratinized thinly and present in less than half the width of jaw sheath. Jaw sheath margins uniformly serrated with small fine serrations; supra-rostrodont longer than wide and convex with median region protruding towards posterior; infra-rostrodont U-shaped, convex laterally and concave medially.

Measurements of 70 tadpoles at various Gosner stages (27‒28, 30‒32, 34‒35, 37‒41, 45) are given in tab. 24 .

Coloration. In preservation, dorsal body dirty yellow with numerous tiny melanophores dotted on dorsum and flanks. Inner integument more spotted than outer. In lateral view, flanks darker than dorsum. Ventral integument dirty white with no melanophores, and translucent with gut coils visible. Musculature of caudal fin light brown mottled with tiny melanophores. Dorsal and ventral fins translucent and white; numerous melanophores scattered on dorsal fin. Spiracle and oral disc translucent and dotted with few melanophores.

Buccopharyngeal morphology. Buccal roof ( fig. 52a‒b ). Prenarial arena of roof with an arched pustulose ridge bearing a pustule on either side lateral to median ridge. Internal nares transverse, oriented medially; gap between nares narrow, about half the length of nare; anterior narial wall pustulose with tiny pustules and a tall, pustulated papilla present medially; posterior wall tall, smooth and valvular. Postnarial arena with a tall conical papilla behind each narial wall oriented medially, pustulated on anterior margin; papillae largest on buccal roof. Median ridge papilla triangular with a pustulated margin. Short stubby pustulated lateral ridge papilla perpendicular to median ridge. BRA demarcated with three pairs of short, conical and pustulated papillae on lateral border of roof; about 30 tiny pustules spread across BRA. Glandular zone thick and prominent with secretory pits. Dorsal velum smooth and discontinuous.

Buccal floor ( fig. 52c‒d ). Prelingual arena composed of two pairs of palps; a pair of stubby papillae located midway and a pair at posterolateral corners of jaw sheath; palps at posterolateral corners long, conical and pustulated; pair of stubby papillae located posteromedially between two posterior palps of the jaw sheath. Tongue anlage broad and raised; two smooth lingual papillae with no pustules present medially on tongue anlage. BFA defined by BFA papillae; four papillae beginning from lateral corners of buccal floor and passing posterior-laterally; papillae conical and tall; second papilla tallest; BFA with 8 to 10 pustules arranged linearly to medial plane of floor. Buccal pockets opening wide and transversely arranged; pre-pocket papillae absent; space between tongue anlage and buccal pockets with about 10‒12 pustules on each side. Ventral velum wide and sinuate. Ventral velum margin with 10 projections on each side. with outer two projections on each side widely spaced; median notch not prominent; outer margin smooth; region between BFA and ventral velum with few pustules. Glottis exposed slightly posterior to ventral velum.

Denticles ( fig. 52e ) moderately spaced and feebly curved towards mouth at apex. Oral angle obtuse with head broadly curved; eight long and curved cusps on each denticle.

Each serration ( fig. 52e ) on jaw sheath with a wide base and a triangular pointed head.

Figures

Figure 51. Chirixalus simus, Gosner stage 37. External morphology: (a) Lateral view, (b) Dorsal view, (c) Ventral view. Scale = 10 mm.

Figure 52. Chirixalus simus, Gosner stage 38. Buccopharyngeal and denticles: (a) Buccal roof, Scanning Electron Microscopy photograph, scale = 0.1 mm, (b) Buccal roof, Alcian Blue stained photograph, ventral view, scale = 0.5 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, scale = 0.01 mm, (f) Jaw sheath serrations = 0.01 mm.