"Other, more bizarre genera include the enigmatic paddlefish Paleopsephurus and the spiny-finned freshwater shark Lonchidion, a holdover from the Triassic period."
―Saurian: A Field Guide to Hell Creek
Lonchidion was a genus of very successful freshwater lonchidiid hybodont that lived through most of the Mesozoic. Fossils attributed to Lonchidion are known from as early as the Triassic to as late as the Cretaceous. Lonchidion has been mostly associated with North America and Eurasia, hinting at a very wide distribution for the genus across different species. Hybodonts like Lonchidion are seen as being generalists, capable of hunting and efficiently killing anything from fish and cephalopods, to shelled crustaceans. It is this adaptability which is seen as the main reason for the success of this genus during the Mesozoic, and it is also mirrored within some of the related genera to Lonchidion such as Hybodus.
In Saurian[]
Lonchidion is expected to appear in Saurian. Its' color is a mostly brown body with a white underbelly, black fin tips, and white spines and yellow eyes to match its' habitat. In the book Saurian: A Field Guide to Hell Creek, it is stated that the Lonchidion is a “spiny-finned freshwater shark...” and a “holdover from the Triassic period.” It also states that the Lonchidion in Saurian is a still yet to be named species and not L. selachos.