Kaloula indochinensis

Vassilieva, Anna B., 2021, Larval morphologyof three syntopic species of Kaloula Gray (Anura: Microhylidae) from Vietnam, Zootaxa 4952 (1), pp. 71-86 : 75-77

Kaloula indochinensis

Tadpole description. External larval morphology of Kaloula indochinensis is described based on ten tadpoles (Stages 36–37) collected from Kon Ka Kinh NP (ZMMU A-7570) and is shown in Fig. 2 A,B ; the main morphometric characters and body proportions are given in Table 3 .

In dorsal view ( Fig. 2A ), body broadly oval, with maximum width at the gills level; snout bluntly rounded. In lateral view ( Fig. 2B ), body depressed dorsoventrally, especially in its rostral part, with a flat dorsum. Eyes lateral, relatively small; pupils oriented laterally. Nostrils closed during mid-larval stages, small darkly pigmented protuberances visible on the snout at their place; nasolacrimal grooves faintly visible. Spiracle ventral, medial, in the form of a tapering tube extending beyond the end of the body and fusing with the vent tube ( Fig. 5A ). Vent tube medial, oblique; vent opening located at the ventral edge of the ventral fin. Tail moderately long (less than twice the body length), lanceolate, with an elongate, narrowly tapering tip. Tail musculature rather weakly developed (tail base nearly a third of the maximal body width). Tail fins relatively tall, reaching their maximum height at the middle third of the tail length. Sheets of slightly thickened skin visible on the sides of the proximal part of the tail (22–25% of tail length), along the muscular part and the bases of the dorsal and ventral fins. Dorsal fin originating slightly posterior to the body-tail junction, nearly equal in height to the ventral fin. Mouth terminal, without keratinized elements. Upper labium widely arched, concave from the dorsal view, with two lateral flaps slightly projecting forwards beyond the snout edge and smoothly curved outwards; lower labium rather narrow, Ω-shaped, with a narrow, smooth, irregularly dentate flange ( Fig. 6A ).

Coloration. Vital coloration is almost uniformly light-brown or dark-brown above, sometimes almost black, with delicate pale-orange or pinkish marble speckling on the tail fins and, sometimes, on the rostral part of the head; belly slightly paler than the back, spiracle and vent tube pigmented equally to the body undersides. The density of the pigmentation in the whole varies greatly with dependence on the illuminance and the water colour. The proximal quarter of the tail is coloured similarly to the body, and the rest of the tail is markedly paler. The iris is dark grey or black, with a thin golden rim around the pupil. In preservative, the brown and orange coloration fade to greyish, and the tail coloration has less contrast.

Geographic variations. In comparison with tadpoles from Kon Ka Kinh NP, larvae of Kaloula indochinensis from Chu Mom Ray NP are more densely pigmented, have slightly longer tails relative to body length and a slightly shorter spiracle tube relative to the vent tube. In contrast, tadpoles from Cat Tien NP display the longest spiracle tubes (markedly longer than the vent tubes), have the narrowest mouths relative to body width, the most developed tail musculature (tail base width more than a third of the body width), and a rather contrasting tail coloration.

Metamorphs. Young metamorphs of Kaloula indochinensis ( Fig. 2C ) have a stocky appearance, tuberous skin, and bulging, lateral eyes. Digits on the forelimbs are rather short, robust, with strongly enlarged trapeziform tips. Ground coloration is brownish-grey, with irregular dark patches: an inverted black T- or Y-shaped pattern is usually present on the dorsum in the scapular area. Whitish or pale-bluish stellar speckling is seen on the dorsal surface of the head, back and limbs. Rear back and tibiotarsal joint are with whitish or grey patches; the upper arms have orange, pale pink or whitish patches. Belly is dark brown, with white or blueish stellar speckling; hind limbs undersides are light brown with grey marbling. SVL 10.80–11.90 (n = 8).

Coexisting tadpoles. In Cat Tien NP, tadpoles of Kaloula indochinensis were observed in temporary ponds with larvae of K. pulchra and other frog species: Glyphoglossus guttulatus (Blyth) , Kalophrynus interlineatus (Blyth) , Microhyla butlery Boulenger , M. heymonsi Vogt , M. mukhlesuri Hasan, Islam, Kuramoto, Kurabayashi & Sumida , M. pulchra (Hallowell) , Micryletta erythropoda (Tarkhnishvili) (Microhylidae) ; Chiromantis nongkhorensis (Cochran) , Feihyla vittata (Boulenger) , Polypedates megacephalus Hallowell (Rhacophoridae) ; Hoplobatrachus rugulosus (Wiegmann) , Occidozyga lima (Gravenhorst) , O. martensii (Peters) (Dicroglossidae) ; and “ Hylarana ” lateralis ( Ranidae ).

Figures

FIGURE 2. External morphology of a Kaloula indochinensis tadpole from Kon Ka Kinh NP (ZMMU A-7570), Stage 35, TL 24 mm, (A) dorsal view, (B) lateral view, and (C) a young metamorph, St. 46, SVL 11.3 mm. Abbreviations: sp spiracle, v vent. Photo by V. Trounov.

FIGURE 5. Spiracle morphology, in ventral view: (A) Kaloula indochinensis ZMMU A-7570, (B) K. mediolineata ZMMU A-7571, and (C) K. pulchra ZMMU A-7575. Abbreviations: sp spiracle, v vent.

FIGURE 6. Mouthparts morphology, in dorsal view: (A) Kaloula indochinensis ZMMU A-7570, (B) K. mediolineata ZMMU A-7571, and (C) K. pulchra ZMMU A-7575. Abbreviations: llab lower labium, ulab upper labium, pap papillae.