High Quality Content by WIKIPEDIA articles! Tunicates, also known as urochordates, are members of the subphylum Tunicata, previously known as Urochordata, a group of underwater saclike filter feeders with incurrent and excurrent siphons that is classified within the phylum Chordata. While most tunicates live on the ocean floor, others such as salps, doliolids and pyrosomes live above in the pelagic zone as adults. Various species are commonly known as sea squirts or sea pork.