Rhizodontida

Rhizodus ("root tooth") is an extinct genus of basal, finned tetrapodomorphs (the group of sarcopterygians that contains modern tetrapods and their extinct relatives). It belonged to Rhizodontida, one of the earliest-diverging tetrapodomorph clades. Two valid species have been described, both of which lived during the Early Carboniferous epoch. The type species R. hibberti is known from the Viséan stage of the United Kingdom, whereas the species R. serpukhovensis is from the Serpukhovian of Russia. Some fossils referred to the genus Rhizodus have also been found in North America.

Rhizodontida is an extinct group of predatory tetrapodomorphs known from many areas of the world from the Givetian through to the Pennsylvanian - the earliest known species is about 377 million years ago (Mya), the latest around 310 Mya. Rhizodonts lived in tropical rivers and freshwater lakes and were the dominant predators of their age. They reached huge sizes - the largest known species, Rhizodus hibberti from Europe and North America, was an estimated 7 m in length, making it the largest freshwater fish known.

Gooloogongia ( ) is a genus of prehistoric lobe-finned fish which belonged to the group of rhizodont fishes. Gooloogongia lived during the Late Devonian period (Famennian stage, about 360 million years ago). Fossils have been found in the Canowindra site, (Australia). It was named by Zerina Johanson and Per Ahlberg in 1998. In general size and shape Gooloogongia is similar to the modern saratoga which lives in the tropical rivers of northern Australia.

Barameda (Indigenous Australian language: "fish trap") is a genus of rhizodont lobe-finned fishes which lived during the Tournaisian stage near the start of the Carboniferous period in Australia; fossils of the genus have been reported from the Snowy Plains Formation. The largest member of this genus, Barameda decipiens, reached an estimated length of around , while the smallest species, B. mitchelli is estimated to have had a length of about .

Strepsodus is a genus of rhizodont lobe-finned fish that lived throughout the Carboniferous period. Fossils have been found in eastern Canada, Britain (England and Scotland), and Queensland, Australia; indeterminate species of Strepsodus have also been found in the late Devonian deposits of Turkey, Iran and Colombia. A large individual is measured up to long.

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