Eugeneodontida (Redirected from Eugeneodontiformes)

Eugeneodontida
Temporal range: 407.7–247.2 Ma Early Devonian to Olenekian
Helicoprion davisii
Edestus heinrichi
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Holocephali
Order: Eugeneodontida
Zangerl, 1981
Synonyms
  • Eugeneodontiformes
Helicoprion bessonovi, teeth at the front of the lower jaw (reversed for more natural position)
Helicoprion bessonovi, hypothetical reconstruction
Restoration of Romerodus

The Eugeneodontida, sometimes also called Eugeneodontiformes, is an extinct and poorly known order of cartilaginous fishes. They possessed "tooth-whorls" on the symphysis of either the lower or both jaws and pectoral fins supported by long radials. They probably lacked pelvic fins and anal fins. The palatoquadrate was either fused to the skull or reduced. Now determined to be within the Holocephali, their closest living relatives are ratfish. The eugeneodonts are named after paleontologist Eugene S. Richardson, Jr. The Eugeneodontida disappeared in the Early Triassic. The geologically youngest fossils of the group are known from the Sulphur Mountain Formation (western Canada), Vardebukta Formation (Svalbard, Norway) and Wordie Creek Formation (Greenland).

Members of the Eugeneodontida are further classified into different families, the most well-preserved members that have been discovered are commonly placed within the families Helicoprionidae ("spiral saws"), and Edestidae ("those which devour"), the former containing the genera Helicoprion, Sarcoprion, and Parahelicoprion, and the latter containing the genera Edestus, Lestrodus, and Metaxyacanthus. All eugeneodonts are thought to have been obligate carnivores, with each genus having specialized feeding behaviors, territory ranges, and specific prey.

Among the eugeneodonts, some members of the superfamily Edestoidea are probably the largest animals of their time during the Late Carboniferous, with Edestus reaching about or exceeding 6.7 metres (22 ft) in length, and with Helicoprion measuring over 7.6 metres (25 ft) long.

Taxonomy

The list below shows taxa included within Eugeneodontida.



This page was last updated at 2024-03-28 20:20 UTC. Update now. View original page.

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