conodont
Pronunciation: /ˈkəʊnədɒnt/
noun
- (also conodont animal) a fossil marine animal of the Cambrian to Triassic periods, having a long worm-like body, numerous small teeth, and a pair of eyes. It is now believed to be the earliest vertebrate.
- Class Conodonta, phylum Chordata: numerous families
- (also conodont element) a tooth of the conodont, often found as a fossil.

Origin:
mid 19th century: from modern Latin Conodonta (plural), from Greek kōnos 'cone' + odous, odont- 'tooth'