''Cobelodus'' is an extinct genus of holocephalid known from the late

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...

to the early

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...

period. The type specimen, assigned to the genus '' Styptobasis'', was discovered by

Edward Drinker Cope Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontologist, comparative anatomist, herpetologist, and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested ...

Illinois Basin The Illinois Basin is a Paleozoic depositional and structural basin in the United States, centered in and underlying most of the state of Illinois, and extending into southwestern Indiana and western Kentucky. The basin is elongate, extending app ...

black coal shales. Rainer Zangerl reassigned ''S. aculeata'' in 1973 to the genus ''Cobelodus'', translating to 'needle tooth'. Cope's description was based from a tooth fragment and was compared to the genus '' Monocladodus''. ''Cobelodus'' differs from ''Styptobasis'' and ''Monocladodus'' in the anatomy of its teeth and pectoral fins. ''Cobelodus'' was an up to long predator. Although it was related to the

chimaera Chimaeras are cartilaginous fish in the order Chimaeriformes , known informally as ghost sharks, rat fish, spookfish, or rabbit fish; the last three names are not to be confused with rattails, Opisthoproctidae, or Siganidae, respectively. At ...

, ''Cobelodus'' had a number of differences from modern forms. It had a bulbous head, large eyes, a high-arched back, and a dorsal fin placed far to the rear, above the

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

s. Another unusual physical feature of ''Cobelodus'' are the long, flexible

cartilage Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck an ...

nous 'tentacles' sprouting from its

pectoral fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

s. Their purpose is unknown. Type species, ''C. aculeatus'' is known from shoreline

lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') a ...

References

Permian fish of North America Symmoriiformes {{paleo-cartilaginous-fish-stub