What are common mistakes students make with the phylum chordata?
A common mistake students make with the phylum chordata is when identifying the features that are shared.
The chordates share these features which all appear at some moment in the life of the organism:
Dorsal hollow nerve cord
Endostyle (homologous to the thyroid in vertebrates
However not all these features are synapomorphies, a shared (by two or more taxa) derived characteristic. Includes the notochord , postanal tail , and endostyle .