Atelopus onorei is only known from near Río Chipla (2 47' 24" S, 79 21' 36" W, ca. 2,500 m asl), 10–15 Km E Luz María, and a nearby creek, in the Azuay Basin of the Cordillera Occidental of Ecuador, Azuay Province, Ecuador (Coloma et al. 2007).
Habitat and Ecology
The species inhabits humid cloud montane forest on the Pacific versant of the Cordillera Occidental. Individuals were found close to running water, and were active during the day, with numerous pairs found in amplexus. A female was found to contain 133 ovarian eggs ca 2.14 mm in diameter. The species occurs in sympatry with A. nanay at one of the localities (Coloma et al. 2007). The species requires a permanent source of water (L. Coloma pers. comm. 2008).
Although this species was previously abundant at the type locality, no individuals have been found after 1990, despite at least four occasional search efforts to locate the species at the same site as before and surroundings (Coloma et al. 2007).
The area of occurrence of Atelopus onorei is close is to areas where climate abnormalities have occurred and Atelopus and Telmatobius extinctions have been reported. They are also close to areas where the chytrid fungus has occurred, or its presence is predicted. Given this scenario and considering the overwhelming evidence that Atelopus has been affected by these two key factors in the highlands, it is likely that A. onorei may be extinct, although the possibility of existing relictual populations may not be overlooked (Coloma et al. 2007).
This species is not known to occur in any protected areas in Ecuador.
Atelopus onorei can be distinguished from other similar species by its colour patterns (Coloma et al. 2007).
Luis A. Coloma 2008. Atelopus onorei. In: IUCN 2014