Cophixalus pipilans Zweifel 1980

Cophixalus pipilans is a small member of the genus, ranging from 18.5-22.3 mm SVL. Its size range differentiates it from most of its congeners along with having a first finger less than half the size of the second and without a broadened disc. Two species share these characteristics, C. ateles and C. shellyi: C. pipilans differs from C. shellyi in leg length (TL/SVL of 0.53+ in C. pipilans and 0.53 mm or smaller in shellyi) and from C. ateles in having a shorter tibial length/SVL ratio. Head is relatively wide with a nearly flat loreal region and an obtusely pointed snout and a rounded canthus. Nostrils are closer to the snout tip than to eye. Eyelids are one-half the width of the interorbital space. Tympanum is about one-half diameter of the eye. Skin is smooth with no obvious folds or warts. Finger relative lengths are as follows: 3>4>2>1, with the first finger less than one-half the length of the second and lacking an expanded disc. Second, third, and fourth fingers with enlarged discs with terminal grooves. Low rounded subarticular and inner metacarpal tubercles barely visible. Toes lack webbing and finges and have the following relative length formula: 4>3>5>2>1. The third toe is much longer than the fifth. Toe discs are larger than those on fingers, that on the fourth toe is approximately two times as wide as the penultimate phalanx. No vomerine, premaxillary or maxillary teeth. Stenrum is cartilaginous and clavicles, procoracoids, and omosternum are absent. Dorsal ground coloration in preservative is pale brown with dark melanophores laterally on body. There is an hourglass shaped mark on the back of the hand and scapular region. Snout region below eye is dark. Anterior and posterior regions of the thighs are darkly reticulated. Chin and chest with a dark stipple of melanophores. In life the dorsum is brown to yellowish tan with a black face mask.

Lowland forests on hillsides at elevasions close to sea level to 50 m (this is for collected specimens, actual distribution may be higher and wider) in the vicinity of Lae, Morobe Province just north of Alexishafen and the Adelbert Mountains in the Madang Province. Range spans 270 km in Papua New Guinea.

Calls are a series of soft high pitched “peeps” in groups of 20-33 with a range of 6 seconds to 2 minutes elapsing between calls. Dominant frequencies range from 4900-5300 at 24-25 degrees celcius.

Cophixalus pipilans is a species of frog in the family Microhylidae. It is endemic to northern mainland Papua New Guinea and occurs between Lae (Morobe Province) and the Adelbert Mountains (Madang Province). The specific name pipilans is derived from the Latin verb pipilio and means "peeping". Common name Sempi rainforest frog has been coined for this species.