Blue-sided Treefrog

Central America


Agalychnis annae


  • Pollution.
  • Loss of habitat.
  • Collection by humans.

Agalychnis annae is a moderately large and slender frog. Males have a maximum snout-vent length of 73.9 mm, and females 84.2 mm. The head is slightly convex and is narrower than the body. Males have a softly sloping snout from the eyes to the nostrils in lateral profile. Females have a blunt snout in lateral profile. The eyes are large and the lower eyelid is reticulate. The dorsal surface is smooth and the venter is faintly granulate.

This frog is quite colorful. In contrast to the uniform green upper surfaces, the proximal dorsal portion of the upper arm is pink to lavender and the distal portion is blue. The flanks and anterior and posterior thigh surfaces are blue. The upper surface of the hands and feet are green, orange, and blue. There are vivid creamy yellow stripes along the ventrolateral margin of the forearm, tarsus and foot. The venter is creamy yellow to orange. This species is able to undergo metachrosis (color change), and the colors darken at night to a darker green and bluish purple. Metamorphs lack blue coloring and turn reddish brown at night and in preservative.

Agalychnis annae is a declining species due to many factors, mainly chytridiomycosis. It has disappeared from many protected areas. This species is now found mainly in metropolitan San José near polluted streams, possibly because the chytrid fungus is more susceptible to pollution than A. annae. Predation on tadpoles from an introduced fish, Xiphophorus hellerii, also impacts this species.