Hemiphractus johnsoni

Hemiphractus johnsoni is thinly distributed over a vast range. It occupies elevations of 300m to 1910m in the Northern Andean slopes of Colombia, the upper Amazon Basin, and lower Amazonian slopes of the Andes from Ecuador to Northern Bolivia (Trueb 1974).

Hemiphractus johnsoni inhabits dense, lowland tropical rainforests (Trueb 1974).

Hemiphractus johnsoni is sexually dimorphic; females are significantly larger than males. Snout to vent length in males averages approximately 52.9mm, while females average 77.2mm in length. There are scattered tubercles on the dorsal surface and forearms, and poorly developed tubercles on the hind limbs, of all hemiphractine species. The granular eyelids also have one or two enlarged conical tubercles. On the tip of the snout of H. johnsoni is a small, triangular and dorsoventrally flattened, fleshy proboscis. The shape of this proboscis is one of the ways H. johnsoni differs from the other hemiphractine species. A unique feature in H. johnsoni is the presence of a small, round post- orbital depression with a light crossbar; conversely H. johnsoni lack the provomerine teeth that other hemiphractine species possess. The color pattern of the dorsum is tan-brown with reddish mottling and darker spots. The forelimbs and hind limbs are a pale ground color with dark transverse. The outer digit of the unwebbed hands are noticebly darker than the inner digits. The back feet have basal webbing and the adhesive discs of the toes are slightly smaller than those of the fingers (Trueb 1974).

When threatened, hemiphractine species show a "gaping behavior" involving the frog opening its mouth as wide as possible. Because the Hemiphractinae lack both vocal sacs and vocal slits, mating calls and breeding congregations are unknown. At night H. johnsoni have been found perched on low branches 0.3m to 0.7m above ground (Trueb 1974).

Little is known of the feeding habitats of H. johnsoni, but insects and other small invertebrates probably constitute most of the diet, as in other hylid frogs. Lizards are not normally part of a small frog's diet, but a lizard was once found in the stomach of a related hemiphractine specie (Trueb 1974).

The population status of this species is unknown, but it is undoubtedly threatened by the destruction of primary rainforest.

Hemiphractus johnsoni is the most generalized species in the subfamily Hemiphractinae. This suggests that it may resemble the ancestral hemiphractine that presumably evolved from a neotropical relative in the family Hylidae ("true" treefrog group) (Trueb 1974). Though interesting in appearance and their reproductive behavior, the Hemiphractinae have not been as thoroughly researched as some other tropical anurans.