Meristogenys macrophthalmus (Matsui 1986)

Meristogenys macrophthalmus is a relatively small member of the M. jerboa species group and measures 37.8 mm SVL for the male holotype. This species has a moderately stout body. The head is broad, the snout is blunt with distinct canthi and the pineal spot is visible. It has a distinct tympanum. Eyes are large and elevated. Vomerine teeth are poorly developed but present in small oblique groups. The tongue is notched, and lacks papillae. The skin texture is shagreened dorsally, and the flanks are coarsely granular. A glandular dorsolateral fold is present. The throat in contrast is smooth, and the chest and abdomen are rugose. In males, paired vocal sacs form gular pouches at the corners of the throat. Distinct nuptial pads for males cover the first finger from its base to the subarticular tubercle. The fingers are relatively slender with the first and second fingers being shorter. Tips expand into discs with circummarginal grooves. The discs of the third and fourth fingers are the largest. Supernumerary metacarpal tubercles are absent. The toe discs are similar in shape and size to those of fingers. Toes are fully webbed with fringing on the first toe. The inner metatarsal tubercle is oval while the outer metatarsal tubercle is round. While the color in life has not been described, in preservative M. macrophthalmus is grayish-brown on the dorsal portion of the head and body. The upper lip is white. An indistinct dark stripe runs from the eye to the tympanum, diverging after the tympanum. One branch cuts behind the tympanum, and the other continues dorsolaterally along the side of the trunk. The dorsal surfaces of the limbs have alternating gray and brown crossbars. The posterior of the thigh is dark-brown with small light spots. The ventral surfaces are white but spotted with melanophores, with few spots on the legs. The anterior part of the thigh is white with indistinct dark bars.The specific name macrophthalmus is derived from the Greek words macros , meaning large, and ophthalmos , meaning eye.

This species is known only from a single specimen collected in June 1964, and formally described in 1986 (Matsui 1986). The holotype was found at Sungai Metallum, in Bintulu District, central Sarawak, Malaysia (on Borneo).

The primary threat to this species is likely to come from habitat loss due to deforestation (IUCN 2008).

Meristogenys macrophthalmus is a species of frog in the family Ranidae. It is endemic to Sarawak in northern Borneo (Malaysia) and is only known from its type locality in the Bintulu District. The specific name macrophthalmus is derived from the Greek words macros (="large") and ophthalmos (="eye") and refers to the large eyes of this frog. Common names Matsui's Borneo frog, large-eyed torrent frog, and big-eyed torrent frog have been coined for it.