Overview
The South American Lungfish (Lepidosiren paradoxa), locally known in South America as the Piramboia, is a living fossil that represents one of vertebrate evolution’s most remarkable bridges between fish and terrestrial four-legged animals. Endemic to the oxygen-starved swamps of the Amazon and Pantanal, this eel-like lobe-finned fish possesses true paired lungs and is an obligate air-breather that will literally drown if kept underwater without access to air.
Biology and Physical Characteristics
Lepidosiren paradoxa has an elongated, cylindrical, eel-like body covered in small, deeply embedded cycloid scales, colored slate-grey to dark chocolate-brown with subtle yellowish-black spots. Its paired pectoral and pelvic fins are modified into slender, highly flexible, whip-like filamentous appendages equipped with sensory chemoreceptors. Inside its skull, it features true vascularized paired lungs connected to its pharynx.
Behavior and Ecology
When seasonal droughts desiccate its swampy wetland home, the South American Lungfish executes an astonishing survival feat: it burrows deep into soft mud up to 50 centimeters down, secretes a thick mucus cocoon that hardens into a moisture-preserving chamber, and enters a state of dormant estivation, breathing atmospheric air through a tiny mud chimney until rainy season floodwaters return months later.
Conservation and Human Impact
Classified as Least Concern by the IUCN, Lepidosiren paradoxa is widely distributed and locally abundant across intact wetland basins in South America. During the breeding season, males develop astonishing branched, highly vascularized feathery filaments on their pelvic fins that release oxygen into their subterranean nesting burrows to prevent their developing eggs from suffocating.
Interesting Factoid
During the breeding season, male South American Lungfishes transform their hind fins into blood-red feathery ‘anti-lungs’ that pump oxygen backward into the stagnant water of their breeding burrows so their babies don’t suffocate.