Here's why:

* Chordates are a diverse group of animals that share specific physical characteristics at some point in their development. These include:

* Notochord: A flexible rod that supports the body.

* Dorsal hollow nerve cord: A tube of nerve tissue running along the back.

* Pharyngeal slits: Openings in the throat that are used for filter feeding in some species.

* Post-anal tail: A tail that extends beyond the anus.

Stingrays, along with other cartilaginous fishes like sharks, belong to the class Chondrichthyes within the phylum Chordata.