Comprehensive DescriptionRead full entry
Boophis lilianae is a small treefrog with the male holotype measuring 18.3 mm SVL and the female paratype 20.0 mm SVL. The head is wide as long and wider than the slender body. Snout is mucronate in dorsal view for the male holotype, truncate in dorsal view for the female paratype, and obtuse in lateral view. Nostrils are directed laterally, distinctly protruding, and closer to tip of snout than to eye. Canthus rostralis is rounded; loreal region slightly concave; tympanum distinct; and supratympanic fold weak. The tongue is narrowly cordiform, posteriorly distinctly bifurcated and half free. Vomerine odontophores are absent. Arms are generally slender with fingers having small weakly developed subarticular tubercles, and lacking distinct metacarpal tubercles. Fingers show basal webbing as well as lateral dermal fringes. Relative length of fingers increases from 1,2,4,3; finger discs are moderately enlarged; and medium-sized nuptial pad on inner side of first finger lacks pigment. Hindlimbs also appear slender with tibiotarsal articulation that reaches the snout tip when hindlimb is adpressed along body. Inner metatarsal tubercle is distinct and elongated, but outer metatarsal tubercle is absent. Webbing between toes is well-developed and lateral dermal fringes are present. Relative toe length increases from 1,2,5,3,4 and toe discs are moderately enlarged. Dorsally the skin is smooth with widely scattered tubercles. Throat and chest are smooth. The belly appears coarsely granular and the skin around the cloacal opening is glandular but lacks enlarged tubercles (Kohler et al. 2008).
In preservative, Boophis lilianae exhibits creamy yellow coloration on dorsal and ventral surfaces. A pink canthal stripe runs from snout tip to upper eyelid, and a thin brown line encircles the nostril. Upper eyelid is covered by brown blotches, bordered by pink spots. Two fine longitudinal parallel stripes appear on mid-dorsum that are formed by rows of pink spots. There is also a small pink fleck on the knee (Kohler et al. 2008).
In life this species shows translucent yellowish green coloration on the dorsum that appears transparent in the groin. A reddish canthal stripe runs from snout tip to upper eyelid. The thin reddish supratympanic line fades at level of urostyle. Upper eyelid is covered by reddish brown blotch, and between the eyes there is a weak brownish triangular fleck. Two fine longitudinal stripes appear on mid-dorsum that extendsfrom behind scapular region to urostyle. Between the stripes there are some irregular pink marbling spots. Reddish brown spots also appear on heel and knee. Dorsal surfaces of fingers, toes, and terminal discs look yellowish green. Ventral surfaces of limbs, chest and throat are colored a green shade of turquoise. Belly is white and bones are green. The inner iris looks silvery grey, with a fine brownish circular line. Outer iris is golden yellow, with a black triangular fleck above and below pupil. Posterior iris has black on the periphery, adjoined by light blue (Kohler et al. 2008).
A diagnosis of Boophis lilianae with other species of the genus Boophis shows that this treefrog is so far the smallest known species in the genus. It is distinguished from members of the B. rappiodes and B. mandraka species groups by a pigmented ventral side and from members of the B. albipunctatus and B. luteus species groups by lack of lateral dermal fringes along lower arm and tarsus. Moreover, it differs from B. baetkei in smaller adult male size (18.3mm SVL in B. lilianae vs. 30.8mm for B. baetkei) and mucronate male snout shape (vs. rounded in B. baetkei) and a relatively smaller tympanum, as well as lacking vomerine odontophores (Kohler et al. 2008; Wollenberg et al. 2008).
This species is dedicated to Liliane Raharivololoniaina who collected specimens of Boophis lilianae and B. baetkei, in recognition of her contribution to the study of Madagascan amphibians (Kohler et al. 2008).