Boophis baetkei is a medium size treefrog; adult males reach up to 30.8 mm SVL. The body appears slender, and the head is slightly wider than long. Snout is rounded in dorsal view, but obtuse in lateral view. Nostrils are directed laterally, nearer to tip of snout than to eye. Canthus rostralis is rounded; loreal region slightly concave. Tympanum distinct and rounded. A distinct supratympanic fold is present. Vomerine teeth are present in two round patches, posteromedian to choanae. Arms and hindlimbs are slender. Fingers have basal webbing and lateral dermal fringes. Relative length of fingers increases from 1,2,4,3. Finger discs are somewhat enlarged with males having a medium-sized nuptial pad on inner first finger. Single, round subarticular tubercles are present on the underside of fingers, but distinct metacarpal tubercles are lacking. Toe webbing is well developed. Toes increase in length from 1,2,5,3,4 and show slightly enlarged discs. The foot has a distinct elongated inner metatarsal tubercle but no outer metatarsal tubercle. Dorsal skin smooth, throat very finely granular, chest smooth, belly coarsely granular, and the area around the cloacal opening is glandular (Kohler et al. 2008).
In life this species exhibits translucent green coloration around the dorsal surface of the head and body. Small reddish and purplish dots are evenly distributed on the flanks, upper limb surfaces, and dorsum. A pinkish golden stripe runs from the snout along the canthus to the upper eyelid, over the eye and above the tympanum and fades at midbody. The head stripe is bordered by a dark red line that turns purplish dorsolaterally to tympanum. The head stripe is also bordered by red spots posteriorly. Heel and knee have pinkish golden flecks encircled by reddish brown. Dorsal parts of fingers and toes are colored yellowish green, with green discs and yellowish green webbing. Ventral surfaces of limbs look translucent bluish green, chest turquoise green, and throat yellowish green. Belly is white and bones are bluish green. Iris appears mainly silvery grey with fine brown spotting and reticulation. Posterior part of iris has a black peripheral arc followed by light blue. Dorsally, the eye periphery itself also has some black (Kohler et al. 2008).
In preservative Boophis baetkei assumes a creamy yellow color on both dorsal and ventral surfaces. Small pink spots are scattered regularly around upper surface of head, dorsum, and upper surfaces of limbs. A pink stripe runs along the tip of the snout to the upper eyelid and fades at the urostyle (Kohler et al. 2008).
Boophis baetkei is distinguished from members of the B. albilabris and B. microtympanum species groups by a green translucent shade in life (versus opaque green) and smaller size. It differs from species in the B. rappiodes and B. mandraka species groups in having a pigmented ventral side (vs. transparent ventral skin and visible inner organs in those species groups). In contrast to B. ulftunni, B. baetkei has larger males (30.8 vs. 21-24 mm SVL), more extensive toe webbing, lacks reddish brown markings and has a gray iris with brown spots and reticulation (vs. bicolored iris with outer gold ring and inner purple ring in B. ulftunni). Compared to B. lilianae, B. baetkei shows the presence of distinct patches of vomerine odontophores, a larger tympanum, and a rounded snout in dorsal view (vs. mucronate snout in the male holotype of B. lilianae and truncate snout in the female holotype of B. lilianae) (Kohler et al. 2008; Wollenberg et al. 2008).
Boophis baetkei is dedicated to Claus Batke. Acting as leader of the "Tropenokologisches Belgeitprogramm" he contributed his personal efforts to establish BIOPAT in 1999. His contributions include the support of biodiversity research and nature conservation in tropical countries, including Madagascar (Kohler et al. 2008).
- Glaw, F., and Vences, M. (2006). A Field Guide to the Amphibians and Reptiles of Madagascar, 3rd Edition. Vences & Glaw Verlag GbR, KÃ¶ln.
- Kohler, J., Glaw, F., and Vences, M. (2008). ''Two additional treefrogs of the Boophis ulftunni species group (Anura: Mantellidae) discovered in rainforests of northern and south-eastern Madagascar.'' Zootaxa, 1814, 37-48.
- Wollenberg, K. C., Andreone, F., Glaw, F., and Vences, M. (2008). ''Pretty in pink: A new treefrog species of the genus Boophis from north-eastern Madagascar.'' Zootaxa, 1684, 58-68.