Question

Which class of chordates existed first on earth?

Answer 1

Answer:

In London, Lankester [31] gave subphylum status to the Urochordata, the Cephalochordata and the Craniata, altogether comprising the phylum Vertebrata. This constituted the first conception of the modern phylum Chordata

Answer 2

Answer:

Pikaia gracilens was one of the earliest chordates discovered to date. Regarding its phylogenetic position, scientists are still unclear. In fact, it is speculated to belong to a stem-chordate that is not closely related to any extant lineage