Question

why are protochordates not grouped under vertebrates?

Answer 1

Vertebrates /ˈvɜːrtɪbrɪts/ comprise all species of animals within the subphylum Vertebrata/-eɪ/ (chordates with backbones. Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 66,000 species described.[4] Vertebrates include the jawless fish and the jawed vertebrates, which include the cartilaginous fish (sharks, rays, and ratfish) and the bony fish.

Vertebrate
Temporal range:
Cambrian–Present,[1] 520–0 Ma[2]

PreЄ

Є

O

S

D

C

P

T

J

K

Pg

N

Individual organisms from each major vertebrate group. Clockwise, starting from top left:

Fire salamander (Amphibia), saltwater crocodile(Reptilia), southern cassowary (Aves), black-and-rufous giant elephant shrew (Mammalia), ocean sunfish (Osteichthyes)

Scientific classificationKingdom:AnimaliaPhylum:ChordataClade:CraniataSubphylum:Vertebrata
J-B. Lamarck, 1801[3]

Answer 2

protochordates r not grouped under vertebrates because there is absence of notochord, Gill slits or pouches, body cavity and they r not triploblastic......hope it helps