Comprehensive DescriptionRead full entry
Amolops bellulus can measure up to 50.1 mm SVL in males and 63.6 mm in females. The head is depressed with a flattened forehead. The tympanum is distinct and very slightly concave. There is a visible pineal organ. The snout is rounded and projects beyond the lower jaw. Canthi are distinct, with the loreal region vertical at the canthus but oblique from the canthus to the mouth. Vomerine teeth are present in two somewhat oblique rows between the choanae. The tongue is shaped like a heart, with a pronounced concavity at the posterior. The body is relatively slender and depressed, with smooth skin except for numerous small tubercles around the vent and the base of the thigh. Wide and flat dorsolateral folds are present, but supratympanic folds and a glandular ridge under the tarsus are lacking. In preservative, the dorsolateral folds may not be evident but the skin along the edge of the dorsum and flanks is thickened (Liu et al. 2000).
The forelimbs are somewhat long with slender, unwebbed fingers. The third finger is the longest, followed by the fourth, first and second. There are large discs with circummarginal grooves on the three outer fingers; however, the first finger has a small disc with no circummarginal grooves. The three outer fingers also have supernumerary tubercles at the base of each finger. Oval and well-developed subarticular tubercles are present, along with flat, fused palmar tubercles. The hindlimbs are long, with the fourth toe the longest, followed by the fifth, third, second and first. All toes possess discs with circummarginal grooves. All except the fourth toe are fully webbed. The inner side of the first toe and the outer side of the fifth toe are fringed. The foot also has oval subarticular tubercles, and a small, oval inner metatarsal tubercle. The outer metatarsal tubercle is lacking (Liu et al. 2000).
Vocal sacs are absent; however, A. bellulus males do have well-developed velvety nuptial pads covering the dorsal and medial surfaces of the first fingers (Liu et al. 2000).
The body and top of the head are beige with green and brown spots. Ventrally, the throat and belly are slightly yellowish, with some grayish brown on the throat and anterior chest. A white band extends along the jaw and from the jaw to the shoulder. A black band runs from the snout tip to the anterior flank, fading to gray at the axillary region. The dorsal flank is brown with green spots while the posterior and lower flanks are bluish-green to olive-green. Limbs are brown dorsally with many olive green spots. Ventrally, the limbs are yellowish with some black-gray. There are distinct black crossbars on the forelimbs, thigh, tibia, and tarsus. Toe webbing is spotted brown. The upper part of the iris is yellow with some brown spots, while the lower half is dark brown (Liu et al. 2000).
The tadpole has a large (about 2/3 of the belly), well-defined abdominal sucker, as is characteristic of Amolops larvae. Tadpoles measure about 36 mm in total length at stage 31 and 63 mm at stage 36. Eyes are small and directed dorsally, with a group of postorbital glands present on each side. The snout is rounded, with the nostrils located slightly closer to the eye than the tip of the snout. The spiracle is on the left. There is a ventral oral disc, with an expanded lower lip and a single row of marginal papillae that has a broad gap anteriorly, as well as submarginal papillae in a single lateral row on either side. The beaks are keratinized and undivided, with the upper beak curved and the lower beak V-shaped. Denticles are present in two undivided rows, with the denticle formula being III: 4 + 4/1 + 1:II. The tail has visibly segmented musculature, convex dorsal and ventral fins, with the dorsal fin wider, and ends in a sharp point. In addition to the postorbital glands, scattered dorsal glands are present, and on the posterior of the belly, two groups of ventral glands can be seen (Liu et al. 2000).
In preservative, the larval color is brown with dark patches (Liu et al. 2000).
The specific epithet bellulus is from the Latin adjective meaning beautiful.
This species is sympatric with Amolops viridimaculatus, Megophrys minor, Rana arnoldi and Torrentophryne tuberospinia.