Overview
Diane’s Bare-hearted Glassfrog (Hyalinobatrachium dianae) made international scientific headlines upon its discovery in 2015 due to its striking, uncanny resemblance to Jim Henson’s iconic Muppet, Kermit the Frog. Endemic exclusively to the premontane rainforest slopes of eastern Costa Rica, this miniature centrolenid amphibian features completely transparent ventral skin that exposes its beating heart, liver, and digestive tract directly to view, serving as a flagship species for tropical stream conservation.
Biology and Physical Characteristics
Hyalinobatrachium dianae is characterized by a bright lime-green dorsal surface with subtle pale yellow mottling, mimicking the translucent underbellies of rainforest leaves. Its large, bulbous eyes feature pure white irises encircled with distinct dark reticulations. Morphologically classified as a ‘bare-hearted’ glassfrog, its pericardium is entirely transparent rather than white, allowing observers to witness the contraction of the red heart muscle beneath transparent abdominal tissues. Its fingers terminate in expanded, sticky adhesive pads adapted for climbing wet leaves.
Behavior and Ecology
Nocturnal and strictly arboreal, Diane’s bare-hearted glassfrog spends its nights perched on the underside of broad leaves overhanging swift mountain torrents. Males emit a unique advertisement call consisting of a rapid metallic, insect-like buzz that differs markedly from other Costa Rican glassfrogs. Females deposit egg clutches on the undersides of leaves, where devoted males guard the gelatinous masses against predatory wasps and desiccation until tadpoles hatch and tumble directly into the rushing stream below.
Conservation and Human Impact
Evaluated as Least Concern by the IUCN, Hyalinobatrachium dianae is safeguarded within Costa Rica’s renowned national parks, including Braulio Carrillo National Park and La Amistad Biosphere Reserve. Because glassfrogs require immaculate, uncontaminated stream water for tadpole development, they are highly sensitive environmental bioindicators. Threats include agricultural runoff, illegal stream diversion, deforestation along watershed buffers, and the emerging impacts of chytrid fungus (Batrachochytrium dendrobatidis).
Interesting Factoid
With its bulbous white eyes, horizontal pupils, and radiant lime-green skin, this tiny glassfrog bears such an uncanny likeness to Kermit the Frog that the resemblance was celebrated worldwide upon its scientific description in 2015.
Last updated: October 2026