#ceratodus

By Ripley Cook

Etymology: Horn tooth

First Described By: Agassiz, 1837

Classification: Biota, Archaea, Proteoarchaeota, Asgardarchaeota, Eukaryota, Neokaryota, Scotokaryota, Opimoda, Podiata, Amorphea, Obazoa, Opisthokonta, Holozoa, Filozoa, Choanozoa, Animalia, Eumetazoa, Parahoxozoa, Bilateria, Nephrozoa, Deuterostomia, Chordata, Olfactores, Vertebrata, Craniata, Gnathostomata, Eugnathostomata, Osteichthyes, Sarcopterygii, Rhipidistia, Dipnoi, Ceratodontiformes, Ceratodontidae

Referred Species: C. africanus, C. carteri, C. diutinus, C. elegans, C. eruciferus, C. felchi, C. fossanovum, C frazieri, C. guentheri, C. gustasoni, C. hierogyphus, C. humei, C. kempae, C. kranzi, C. latissimus, C. molossus, C. nirumbee, C. robustus, C. stewarti, C. szechuanensis, C. texanus, C. tunuensis

Status: Extinct 

Time and Place: 252 to 55 million years ago, from the Induan of the Early Triassic to the Ypresian of the Eocene.

Ceratodus is known from the United States, Peru, Uruguay, Greenland, Svalbard, South Africa, Madagascar, Morocco, Libya, Mali, Niger, Egypt, Sudan, Saudi Arabia, France, Spain, Switzerland, Liechtenstein, Germany, England, Russia, India, Mongolia, Thailand, and Australia.

Physical Description: Ceratodus is... a lungfish. Most of the fossil remains are distinctively-shaped teeth. These teeth are multicusped and in life would be incorporated into a solid crushing surface with other tissues in the mouth. Externally it would have looked very much like the Queensland lungfish. In fact, it used to be considered a species of Ceratodus, until it was moved to the genus Neoceratodus in 1977. Ceratodontiform morphology has changed little in the intervening time. Look at a lungfish and you know what Ceratodus was like.

Diet: Ceratodus would have eaten fish, small amphibians, a variety of invertebrates, and possibly plant matter, much like its living relative.

Behavior: Ceratodus is probably best compared to a fallen log. It would have sat quietly at the bottom of calm waters, waiting for food to come on by. It was likely primarily nocturnal, and more mobile at night. As a lungfish, it would have been able to breathe air, and thus would be able to survive its habitat drying up. Going off its modern relatives, it may have been able to live for absurdly long periods of time if left alone - captive Queensland lungfish can and have reached their 90’s.

Ecosystem: Ceratodus fossils are known from pretty much everywhere. In the Triassic, Ceratodus is known from North America, Europe, western Asia, India, and Australia. Most Ceratodus-bearing habitats were marshlands or other calm freshwater environments. Other Ceratodus-bearing sites are marine, meaning the Ceratodus found there were probably washed out to sea. The seasonal wetlands Ceratodus probably favored were also frequented by sharks such as Hybodus and xenacanthids, ray-finned fish, temnospondyls, and phytosaurs. The exact species vary by location; in North America, Ceratodus lived alongside phytosaurs like Rutiodon and Smilosuchus, while in Eurasia temnospondyls such as Metoposaurus and Cyclotosaurus were more common. Of course, many land-living animals would have come by these rivers to drink, such as cynodonts, rhynchosaurs, pseudosuchians, and early dinosaurs. To go more in-depth would make this article three times as large as it currently is.

Other: There’s a town in Queensland called Ceratodus.

~ By Henry Thomas

Sources under the Cut

A belated day 25 for Dinovember, a Spinosaurus catching a large neoceratodus in the shallows.