Meristogenys maryatiae inhabits rocky streams in lowland and hillside forests of Sabah. The species was described by Matsui et al. (2010). The type locality is Ulu Kimanis, on the western slope of the Crocker Range, Sabah, at 155 m a.s.l. This species is so far only known from western Sabah, below 1000 m a.s.l.

M. maryatiae is a relatively small form of the genus, measuring 31–37 mm SVL (snout–vent length) in males; females measure approx. 65 mm. The head is narrow, with its width representing 32–36 % of SVL. The upper and lower halves of the iris are golden, with darker, reddish sectors in between. As in all species of the genus, the legs are long (tibia length / SVL = 66.8–77.5 %).

The snout is moderately short, shorter than the eye, pointed at the tip in dorsal view, projecting in profile, and extending beyond the lower jaw. The canthus is sharp. The pupil is horizontal. The eardrum is distinct, measuring about two-thirds of the eye diameter. The eardrum and eye are separated by a gap equal to one-sixth of the tympanum diameter. There are paired subgular vocal sacs that form gular pouches at the corners of the throat, and the vocal openings are located just inside the commissures of the jaws.

The fingers are slender. The first finger is slightly longer than the second, and the fourth finger is much longer than the second. The fingertips are expanded into discs with circummarginal grooves. There is no webbing between the fingers and no fringes of skin along their sides. The subarticular tubercles are oval and distinct. The inner palmar tubercle (on the underside of the hand) is distinct, while the two outer palmar tubercles are elongate but indistinct. There are no supernumerary metacarpal tubercles.

The hindlimbs are long, more than three times the length of the forelimbs. The tibia (shank) is long, and the heels overlap when the limbs are held at right angles to the body. When the hindlimb is adpressed, the tibiotarsal articulation reaches far beyond the tip of the snout. The toe discs are similar in shape and size to those of the fingers. The toes are fully webbed, with the webbing reaching the discs of all toes. The subarticular tubercles are oval and distinct. The inner metatarsal tubercle is oval. There is also a small, rounded outer metatarsal tubercle.

The dorsum is shagreened, with a low, indistinct dorsolateral fold. The sides of the trunk are coarsely granular. There is only a faint fold above the eardrum.

In life, the back is olive-brown with dark spots. A faint dark marking is present below the canthus on each side of the snout. The upper lip is light brown with a few darker spots. The iris is a uniform golden color (Fig. 3A). A blackish-brown band surrounds the eardrum, which itself is dark brown with a lighter center. The limbs show alternating light and dark brown crossbars, with the darker bars noticeably wider. The rear of the thighs is dark brown, mottled with irregular light spots. The lower lips have faint light-brown barring. The throat, chest, and belly are whitish, except for the vocal sac, which is light brown (Fig. 1B). The undersides of the legs are slightly darker but lack any black pigment dots, and the toe webs are blackish-brown.