Echidnocephalus

Echidnocephalus
Temporal range: Possible Coniacian and Maastrichtian occurrence
Fossil of Echidnocephalus troscheli
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Notacanthiformes
Family: Halosauridae
Genus: Echidnocephalus
von der Marck, 1858
Type species
Echidnocephalus troscheli
von der Marck, 1858
Species
  • E. troscheli von der Marck, 1858
  •  ?†E. americanus Cockerell, 1919
  •  ?†E. pacificus Cockerell, 1919

Echidnocephalus (Greek for "Echidna's head") is an extinct genus of prehistoric halosaur known from the Late Cretaceous. It is the earliest known definitive member of the order Notacanthiformes.

It contains one definitive species known from complete and partial specimens: E. troscheli (=E. tenuicaudus von der Marck, 1858) from the late Campanian-aged Ahlen Formation of Westphalia, Germany. These body fossils suggest an animal already very similar to modern halosaurs.

In addition, two disputed species known only from isolated fossil scales very similar to those of modern halosaurs have been described from North America: ?E. americanus Cockerell, 1919 from the Coniacian-aged Mancos Shale of Wyoming and ?E. pacificus Cockerell, 1919 from the Maastrichtian-aged Moreno Formation of California.