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Which chordate subphyla are invertebrates?
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Chordate
X-ray fish (Pristella maxillaris), is an example of a chordate with a visible backbone.
Within the phylum Chordata, the subphyla that are classified as invertebrates are the Tunicata (also known as Urochordata) and the Cephalochordata.123
Collectively, these two groups are often referred to as protochordates. Unlike the third subphylum, Vertebrata, which is characterized by the presence of a backbone, these invertebrate chordates lack a vertebral column. While they share fundamental chordate features—such as a hollow dorsal nerve cord, pharyngeal gill slits, and a notochord—they do not develop the bony or cartilaginous vertebrae that replace the notochord in most vertebrates.243