Arganodus is an extinct genus of freshwater
lungfish that had a wide global distribution throughout much of the
Triassic period, with a single species surviving across
Gondwana into the
Cretaceous.[1] It is the only member of the family Arganodontidae, although it is sometimes placed in the
Ceratodontidae or synonymized with the genus Asiatoceratodus.[2][3][4]
Indeterminate specimens have been found in the
Redonda Formation,
New Mexico and the
Cumnock Formation,
North Carolina, although the North Carolinian specimens are smaller than most recorded specimens.[9][10][11] Other indeterminate remains are also known from the Late Triassic of India and
Turkey.[4] Possibly the oldest records of the genus are probable remains from the
Induan of northwestern Australia.[4] It has been suggested that shortly after the origin of Arganodus in the early Triassic, it spread into what is now Europe, evolving into A. multicristatus. Before the Late Triassic, it diverged into two
vicariant lineages separated by the
Central Pangean Mountains: A. atlantis in the east, and A. dorotheae & the Cumnock species in the west, while going extinct in the European region. It eventually went extinct in
Laurasia, but one species, A. tiguidensis, managed to survive in
Gondwana throughout the Jurassic and Cretaceous.[4]
Kemp (1998) placed Arganodus as a synonym of Asiatoceratodus, and this taxonomy has been followed by many other authors, although others still retain them as different genera and families.[3][4]
Paleoecology
Arganodus was probably similar to modern lungfish, and lived in underwater burrows during dry periods until
monsoons occurred.[6]
^Martin, M. (1979). "Arganodus atlantis et Ceratodus arganensis, deux nouveaux Dipneustes du Trias supérieur continental marocain [Arganodus atlantis and Ceratodus arganensis, two new dipnoans from the continental Moroccan Upper Triassic]". Comptes Rendus de l'Académie des Sciences à Paris. 289: 89–92.
^Soto, M., and D. Perea. 2010. Late Jurassic lungfishes (Dipnoi) from Uruguay, with comments on the systematics of Gondwanan ceradontiforms. Journal of Vertebrate Paleontology 30. 1049–1058. .