South American lungfish

The South American lungfish is most closely related to the African lungfishes (family Protopteridae), and both families are thought to have diverged during the Early Cretaceous. Some papers suggest classifying both Lepidosiren and Protopterus within Lepidosirenidae, though authorities continue to classify both as distinct families.''' ==Description==

The immature lungfish is spotted with gold on a black background; in the adult, this fades to a brown or gray color. Its tooth-bearing premaxillary and maxillary bones are fused as in all Dipnoi. South American lungfish also share an autostylic jaw suspension (where the palatoquadrate is fused to the cranium) and powerful adductor jaw muscles with the other extant Dipnoi. Like the African lungfishes, this species has an elongated, almost eel-like body. It may reach a length of . The gills are greatly reduced and essentially non-functional in the adults. Juvenile lungfish feed on insect larvae and snails, while adults are omnivorous, adding algae and shrimp to their diets, crushing them with their heavily mineralized tooth-plates. The fish's usual habitats disappear during the dry season, so they burrow into the mud and make a chamber about down, leaving a few holes to the surface for air. When the rainy season begins, they come out and begin to mate. The parents build a nest for the young, which resemble tadpoles and have four external gills. To enrich the oxygen in the nest, the male develops highly vascularized structures on his pelvic fins that release additional oxygen into the water. As of August 2024, L. paradoxa has one of the longest genomes of any species (91 billion bases, 30 times as many as the human genome). The largest genome belongs to the marbled lungfish, with 130 billion bases. PiRNA, a type of RNA that normally suppresses transposon activity, was found in low levels in the animal and is possibly among the causes of such a large genome. == See also ==