the specimens from Ecuador are perezi type, while in the Peruvian specimens this type only accounts for 62.5%. There are also other obvious geographical differences, such as absence of vomerine teeth and the development of a wart on the snout tip. A later study in 1990 by Duellman dug deeper into this topic by looking into dorsal skin structure and ventral color pattern. The dorsal patterns were classified into five categories based on smoothness, and each geographical area was dominated by populations of a specific type of pattern. The ventral color was also classified into five groups based on the pattern of black and white patches. The range of each group is highly correlated with the distribution of river systems, which include Rio Purus, Rio Madre de Dios, Rio Ucayali, and Rio Tapiche. One explanation for why populations of Perez’s snout frog differ so much from each other is historical climatic-ecological changes. During Pleistocene, the rivers coming down from Andes carried a greater volume of melting galcier water than today, thus isolating the frogs into different basins and causing these populations to evolve independently. The present-day pattern categories also correspond to geographical segregation in history. Habitat and distribution Perez’s snouted frog is commonly found in the upper Amazon Basin in Ecuador and Peru. Its sister species E. nasuta has a much smaller range and is only found in Peru. Some populations of E. perezi are also documented in southern Colombia and Brazil. They range from basins that are only 200m in elevation to 1100m on the eastern slopes of the Andes Mountains. They are a diurnal and terrestrial frog species. Typical habitats are forest floors covered with leaf litter in lowland tropical rainforests. They are well adapted to both primary and secondary forests. Diet Perez's snouted frog is a "sit-and-wait" predator that relies on its cryptic coloration to hide from prey. This allows the frog to prey on mobile arthropods such as cockroaches, spiders, and crickets in the leaf litter. It is thought E. perezi only feeds a few times per day. Tadpoles primarily feed on detritus in the bottom of the pools where they hatch, although there have been reports of tadpoles cannibalizing eggs and other larvae. Mating Perez’s snouted frogs breed opportunistically, usually right after a storm. During amplexus, females usually carry males to the edge of the pool, where they build foam nests together. Water is important