Osteocephalus yasuni

Males measure 44–56 mm (1.7–2.2 in) and females 43–62 mm (1.7–2.4 in) in snout–vent length. The dorsum is brown with dark brown spots. The ventral coloration varies, from bright yellow to yellowish cream in adult males and cream in adult females. Males have rough skin while females have smooth skin. It has expanded discs on the fingers.^[3]

The species' natural habitats are tropical primary moist forests, in both terra firme and seasonally flooded forests. It breeds in temporary pools.^[1] It is nocturnal, although during some months males can be heard calling during the daytime.^[3]

It is locally affected by habitat loss, but there are no major threats to this reasonably abundant and widespread species. It occurs in a number of protected areas, including its namesake Yasuni National Park.^[1]