Conodont

Conodonts Temporal range: Cambrian to Earliest Jurassic (Hettangian) PreꞒ Ꞓ O S D C P T J K Pg N
Conodont elements
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Subphylum:	Vertebrata
Class:	†Conodonta Pander, 1856
Subgroups
Cavidonti Proconodontida Conodonti Protopanderodontida Panderodontida Prioniodinida Ozarkodinida
Synonyms
†Conodontophorida Eichenberg, 1930[1] †Euconodonta

Conodonts (Greek kōnos, "cone", + odont, "tooth") are an extinct group of eel-looking agnathan (jawless) vertebrates, classified in the class Conodonta. For many years, they were known only from fossils of their spiky oral elements, which are usually found in isolation and are now called conodont elements, while knowledge about soft tissues remains limited. A resilient group of prehistoric fish, conodonts existed in the world's oceans for over 300 million years, from the Cambrian to the beginning of the Jurassic. Due to their cosmopolitan distribution, conodont elements are widely used as index fossils, fossils used to define and identify geological periods.