''Listracanthus'' is a genus of extinct

chondrichthyan Chondrichthyes (; ) is a class that contains the cartilaginous fishes that have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fishes'', which have skeletons primarily composed of bone tissue. C ...

with uncertain affinities. Species of ''Listracanthus'' are known primarily from their tremendous, feather-like denticles, which range up to four inches in length. The denticles had a large main spine, from which secondary spines emanate from the sides, like the barbs of a feather or a comb. ''Listracanthus'' first appeared in late Carboniferous strata in North America, and eventually disappear from the fossil record some time during the Early

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

The appearance of these sharks are largely unknown. However, author and illustrator Ray Troll mentions in his book, ''Sharkabet'', about how paleontologist

Rainer Zangerl Rainer may refer to: People * Rainer (surname) * Rainer (given name) Other * Rainer Island, an island in Franz Josef Land, Russia * 16802 Rainer Year 168 ( CLXVIII) was a leap year starting on Thursday (link will display the full calendar ...

once discovered a large shale slab containing a long, eel-like fish covered in long, spine-like denticles characteristic of the genus, only to have it dry out and crumble into dust. As such, according to Zangerl's account, Troll reconstructs ''Listracanthus'' as resembling a tremendous, fiercely bristled frill shark. Martill et al., (2014) created the genus '' Acanthorhachis'' for the species formerly known as ''"Listracanthus" spinatus'' (Bolton, 1896). They also erected the family

Listracanthidae Listracanthidae is a proposed family of extinct cartilaginous fish. It currently includes the genera ''Listracanthus'' and ''Acanthorhachis''. This clade is likely included within Elasmobranchii, but its placement within it is uncertain. Both ge ...

to encompass the two genera.

References

Prehistoric fish of North America Prehistoric cartilaginous fish genera Carboniferous cartilaginous fish Permian cartilaginous fish Triassic cartilaginous fish Pennsylvanian first appearances Early Triassic extinctions {{paleo-cartilaginous-fish-stub