A fork-tailed shark from 400 million years ago

Cladoselache is a genus of extinct shark that had existed during the Devonian period. It grew to be up to 5.9 feet long and roamed the oceans of North America. It is known to have been a fast-moving and agile predator because of its streamlined body and forked tail. Cladoselache is one of the best known of the early sharks. Its fossils were well preserved fossils that were discovered in the Cleveland Shale on the south shore of Lake Erie. They even included traces of muscle fibers, kidneys and other organs, and skin.

Family: †Cladoselachidae


Genus: †Cladoselache

Species: †acanthopterygius, brachypterygius, clarki, desmopterygius, fyleri, kepleri, magnificus, newmani



Phylum– Chordata

Class– Chondrichthyles

Order– Cladoselachiformes

Family– †Cladoselachidae

Genus– †Cladoselache

Species– †acanthopterygius, brachypterygius, clarki, desmopterygius, fyleri, kepleri, magnificus, newmani

Status: EXTINCT. Devonian period, lived 400 million years ago.

Average Size and Length: Its average length was 5.9 feet based on fossil records.

Teeth and Jaw: Its mouth was on the front of the head, and terminal. It had a very weak jaw joint compared with modern-day sharks, but it compensated for that with very strong jaw-closing muscles. Its teeth were multi-cusped and smooth-edged, making them suitable for grasping, but not tearing or chewing.

Head: Cladoselache had a short-rounded snout.

Denticles: It had sturdy but light-weight fin spines were composed of dentine and enamel. Cladoselache was almost entirely devoid of scales with the exception of small cusped scales on the edges of the fins, mouth and around the eyes.

Tail: Forked tail ideal for fast swimming.

Demographic, Distribution, Habitat, Environment and Range: North America Europe: Pangea. The best-preserved fossils were discovered in Cleveland Shale on the south shore of Lake Erie.

Diet: Within the gut of most Cladoselache fossils were remnants of their stomach contents. These remains included mostly small ray-finned bony fishes, as well as shrimp-like fish and hagfish-like proto-vertebrates. Some of the fish remains were found tail first within the stomach.

Research suggests they swallowed their prey whole since their teeth were not designed for cutting. Possibly grabbing prey by its tail. Possibly by chasing, prey downwards and out-swimming them, then grasping on to their tails.

Its probable predator, the heavily armored 20-foot-long placoderm fish Dunkleosteus.

Aesthetic Identification: Cladoselache fossils have been well preserved when discovered. The fossils were so well preserved that they included traces of skin, muscle fibers, and internal organs, such as the kidneys. It had a streamlined, fusiform body. It had spiny fins, comb crests, 5-7 gill slits, two pectoral fins, two pelvic fins and a forked tail. Cladoselache also had a blade-like structure which was positioned in front of the dorsal fins.

Cladoselache had keels that extended onto the side of the tail stalk and a semi-lunate tail fin, with the superior lobe about the same size as the inferior.

It had anatomical features similar to the current mackerel sharks of the family Lamnidae.

Biology and Reproduction: Reproduction is still a mystery to scientists because Cladoselache did not have claspers. Some researchers are researching if internal fertilization was a possibility.

Speed:  Research suggests Cladoselache were fast and agile predators in the water.