Sphaerotheca breviceps ( Schneider, 1799 )

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 : 44-48

S10. Sphaerotheca breviceps ( Schneider, 1799) ( fig. 22‒23 )

Larval series examined. WT 102, WT 114 and WT 123 ( North Orissa University ( NOU), Baripada, Odisha, India; 21.929389 N, 86.765389 E). Tadpoles of this species were reared from eggs of taxonomically identified Sphaerotheca breviceps collected on the university campus. In nature, tadpoles were found in small temporary pools and water ditches during early monsoon rains .

Notes. The tadpole specimens were preserved in 10 % buffered formalin, and therefore molecular data could not be obtained. Detailed descriptions of external tadpoles for this species were given by Rao (1915) and Mohanty-Hejmadi et al. (1979).

External morphology. Description of a tadpole at Gosner stage 37. Body ovoid and globular in dorsal and lateral perspectives ( fig. 22a‒b ). Body length 35.2 % of total length; maximum body diameter at the centre of abdomen. Snout acutely rounded in dorsal and lateral perspectives. Eyes large, located and oriented dorsolaterally; distance between eye and nostril 40.7 % of distance between eye and snout. Nostril opening spherical, closer to eyes than to snout, placed parallel to eye in dorsal view; inter-narial distance 63.1 % of inter-orbital distance, distance between nostril and snout 16.6 % of body length. Spiracle sinistral; inner wall of tube completely formed and attached to body wall; tube orientation posterolateral, its opening located above the medial of the lateral side of body. Distance between spiracle and snout 67.7 % of body length. Opening of vent tube dextral. Tail tip pointed; musculature linear on first third length of tail, tapering beyond junction between body tail; ventral fin originating at ventral terminus; dorsal fin wider than ventral fin; maximum height of caudal fin at about mid-length. Height of tail muscle 1.05 times width of tail muscle at body-tail junction. Tail (caudal) musculature accounting for 57.5 % of height of tail. Lateral line faintly visible. Glands absent on outer integument.

Oral disc nearly ventral in location ( fig. 22c ). Rostral width of oral disc 39.6 % of maximum body width, emarginated, not visible dorsally; single row of marginal papillae on labia and lateral commissures; marginal papillae broadly interrupted on both labia medially; two to three submarginal papillae seen at lateral commissures; both labia of equal size. Labial tooth row formula A2(2)/P3. Order of lengths of labial tooth rows A1> P1> P2> A2> P3. Jaw sheaths well developed, and delicately keratinized; pigmentation of jaw sheaths present only on borders. Serrations on lower jaw sheath larger than serrations on upper jaw sheath; supra-rostrodont longer than wide, convex, with median protruding towards posterior; infra-rostrodont U-shaped, convex laterally and concave medially.

Measurements of 20 tadpoles at various Gosner stages (34, 37‒43, 45) are given in tab. 10 .

Coloration. In life, dorsal body and flanks dirty yellow with dark spots. In lateral perspective, flanks comparatively lighter than dorsum. Ventral integument transparent with gut coils visible. Both fins transparent with tiny melanophores mostly on dorsal fin. Laterally, Caudal fin bicolored with dirty yellow background and brown spots extending across tail. Spiracle and vent tube translucent and devoid of pigmentation; oral disc dotted with few melanophores.

Buccopharyngeal morphology. Buccal roof ( fig. 23a ). Prenarial arena of roof with a few pustules anteriorly and a pustulose transverse medial ridge; single pustule present at lateral corners of the ridge. Internal nares transverse, oriented anteromedially; gap between both nares wide, about the length of each nare; anterior narial wall pustulose with a few pustules and a tall, flattened papilla with a pustulated margin at lateral corners of wall; posterior wall smooth and valvular. Postnarial arena with two pairs of papillae; a tall, broad papilla with an irregular anterior margin present immediately behind posterior narial wall and oriented medially; second small conical papilla present at lateral corners of postnarial arena; region before median ridge with about eight pustules. Median ridge papilla triangular with a broad pustulated margin. Two lateral ridge papillae perpendicular to median ridge papilla; a short conical anterior papilla and a broad bifid papilla with a rugose anterior margin. BRA well defined with five pairs of long conical pustulated papillae of varied sizes present on lateral border of the roof; about 40 tiny pustules spread across entire BRA. Glandular zone broad and prominent; secretory pits evenly distributed. Dorsal velum margin raised and continuous with many projections, laterally tall and medially very low.

Buccal floor ( fig. 23b ). Prelingual arena composed of 5‒6 pustules at anterolateral corner and a pair of palps at posterolateral corner on each side of jaw sheath; anterior palp short and stubby with a rugose margin; posterior palp long, broad and rugose located at posterolateral corners of jaw sheath oriented towards medial of prelingual arena; a pair of papillae with pustulsted tips located posteromedially between the two posterior palps. Tongue anlage broad; two pair of long, conical and pustulated lingual papillae located medially; papillae tubular with medial pair longer. BFA defined by six pairs of BFA papillae; papillae beginning from anteromedial of buccal pocket continue parallel to mesad plane converging at posterior region of the floor; all papillae conical, tall, rugose and of unequal size; BFA smooth with 14-16 pustules. Space between tongue anlage and buccal pockets with four to five pustules. Buccal pockets wide and transverse, orienting 45 degrees to mesad; pre-pocket papillae absent. Region behind BFA and margin of ventral velum broad and smooth. Ventral velum wide and sinuate. Ventral velum margin smooth with eight projections; Median notch not prominent. Glottis exposed posterior to ventral velum.

Denticles ( fig. 23c ) spaced moderately and strongly curved towards mouth at apex. Oral angle straight with head slightly curved; sheath thin with body slightly broader; broad head with 12‒14 short and strongly curved cusps.

Serrations ( fig. 23d ) on jaw sheath with a wide base and a triangular head.

Figures

Figure 22. Sphaerotheca breviceps, Gosner stage 37. External morphology: (a) Lateral view, (b) Dorsal view, (c) Ventral view. Scale = 10 mm.

Figure 23. Sphaerotheca breviceps, Gosner stage 37. Buccopharyngeal and denticles: (a) Buccal roof, Scanning Electron Microscopy photograph, scale = 0.2 mm (b) Buccal floor, Scanning Electron Microscopy photograph, scale = 0.2 mm, (c) Individual denticles, scale = 0.01 mm, (d) Jaw sheath serrations = 0.02 mm.