Hylarana (Abavorana) decorata is a robust, medium-sized frog. Adult males reach up to 56 mm in snout–vent length (SVL), while adult females are slightly larger, up to 58 mm. The species has been reported from various locations across Sabah, Sarawak, and Kalimantan. It was included in Hylarana (Abavorana) luctuosa for a long time but Quah et al. (2021) realized that it is in fact an almost forgotten old species originally described as Rana decorata by Mocauard, 1890. Quah et al. (2021) reestablished the species and it is currently grouped under the genus Hylarana.

 

Vocal sacs are absent in males of this species. The first finger is longer than the second. A dorsolateral fold is either indistinct or absent, but a dorsolateral line—white or yellow in color—is present. Humeral glands are prominent in males; they are raised and centrally located on the ventral surface of the upper arm. The outer metatarsal tubercle of the foot is weak or absent. The dorsal skin is smooth or finely shagreened; the throat, abdomen, and flanks are smooth. The posterior belly and the back of the thighs have a rugose (wrinkled) texture. The eardrum is as dark as the surrounding skin and lacks a pale margin.

 

The dorsal coloration ranges from reddish-orange to rust-brown, bordered by a white or cream dorsolateral line that extends around the snout, along the canthus rostralis, the outer margin of the upper eyelids, and down the back, continuing along the dorsolateral fold to the vent. The lower flanks are dark brown or black below the dorsolateral line, fading into a paler ventral surface. The limbs are light grey or brown, speckled and marked with distinct dark brown or black transverse bands.

 

Hylarana decorata can be distinguished from Hylarana (Abavorana) luctuosa by its underside coloration, which features a black-and-white reticulated pattern, particularly on the lower flanks. The limbs, especially the hind limbs, display a striking black-and-white banding. Additionally, a prominent white streak runs from beneath the eye and/or eardrum to the corner of the jaw in H. decorata—a feature absent in H. luctuosa. In some areas, both species have been reported to be sympatric. This raises the question in what parameters they differ ecologically. Clearly more research is needed. 

 

The tadpoles have not yet been distinguished from those of H. luctuosa, as they are very similar. They inhabit stagnant or nearly stagnant bodies of water such as ponds and intermittent streams. The tadpoles live close to the bottom and can grow quite large—up to 70 mm in length. They are capable of escaping predators through sudden, rapid bursts generated by their strong tail.