Mokèlé-mbèmbé Bichir

P. mokelembembe is the smallest extant Polypterid, reaching a maximum recorded adult length of 14 inches (36 cm). It is somewhat similar in appearance to P. retropinnis, which it was once considered to be conspecific with, but differs in maximum adult size, patterning, coloration, scale count, and fin ray count. They exhibit countershading, with a dark green or yellowish dorsal side with brown blotching and a cream-colored underside. Depending on the substrate they are kept on, their colors can vary wildly; they are a dull brownish-green on light-colored sand, but turn a very vibrant green on dark sand. They also exhibit a continuous, dark-colored suborbital stripe along their cheeks and lips that starkly contrasts against their rather plain coloration, as well as dark-colored nares and distinct barring on the pectoral and caudal fins. Their irises are also often a deep red color, which is another distinguishing trait of this species. Like all bichirs, they are amphibious fish. They occur in densely vegetated streams and swamps where seasonal droughts deplete their ability to process oxygenated water. As a "living fossil," one of their stabilomorphic traits is that similarly to stem-tetrapods, they use a blowhole-like organ called a spiracle to take breaths of atmospheric oxygen. If their gills remain sufficiently wet, they can survive on land indefinitely. …

The species was named after the Mokèlé-mbèmbé, a mythological creature believed by some to be a sauropod dinosaur that survived the extinction of dinosaurs in the central Congo Basin. This is in reference to the fact that Polypteriformes are stabilomorphic organisms, or "living fossils," and existed at the same time as non-avian dinosaurs, and the fact that P. mokelembembe is itself endemic to the Congo Basin.