Gonatodes concinnatus Collared Forest Gecko
Some other names for this species:
O’Shaughnessy’s Gecko
Madre Selva Biological Station, Loreto, PeruJanuary 15, 2013
Collared Forest Gecko (Gonatodes concinnatus) Collared Forest Gecko (Gonatodes concinnatus)
Gonatodes concinnatus, unlike its very similar-looking cousin Gonatodes humeralis, is generally found on tree trunks well within the forest, not at forest edges or in human habitations. Consequently they are seen significantly less often, except of course by the people hiking in the forest looking for herps.

Here is a complete list of the herps I saw in the wild on my 2013 MT Amazon Expeditions trip.

Madre Selva Biological Station, Loreto, PeruJanuary 15, 2013
Collared Forest Gecko (Gonatodes concinnatus)
Like several other diurnal Amazonian lizards, these geckos can often be found sleeping at night on large flat leaves. Often they exhibit very pale colors when doing so. I'm thinking this one might be a gravid female, with that darker gray/blue area being an egg.
Santa Cruz Forest Reserve, Loreto, PeruJanuary 21, 2013
Collared Forest Gecko (Gonatodes concinnatus)
Here's a male showing off his bright breeding colors. He was in this awkward-looking position on a large tree trunk at night.
Printed references: