The family Dendrobatidae is distributed in the Neotropics and contains 267 species (AmphibiaWeb 2009; including species of Aromobatidae and Dendrobatidae sensu Grant et al. 2006). Unlike most anurans, poison dart frogs are diurnal and often times show colorful, aposematic coloration. Also, dendrobatids present elaborated reproductive modes, with different types of parental care (Zimmerman, 1990). In YBS, only one species of dendrobatid has been found, Hyloxalus pulchellus. We follow the taxonomy proposed by Grant et al. (2006), as modified by Santos et al. (2009).
Hyloxalus pulchellus (Plate 2). Described by Jiménez de la Espada (1871). This species is characterized by having a dark brown dorsum, thin cream lateral stripe, dark brown to black flanks, and a bluish-white venter with grayish-black reticulation. In adult males, SVL 17.3–21.5 mm (n = 44); 19.6–24.4 mm (n = 16) in adult females (Coloma 1995).
Remarks. Hyloxalus pulchellus exhibits morphological and color variation along its distribution —inter- Andean páramos of southern Colombia and northern Ecuador, and on the eastern slopes of the Andes from southern Colombia to the headwaters of the Río Pastaza in Ecuador, at elevation between 1590 and 2970 m) — and it has been suggested that it might represent a complex of species (Coloma 1995).