Tunicate

Rare card · No. 53376

Tunicates are marine invertebrates belonging to the subphylum Tunicata ( TEW-nih-KAY-tə). This grouping is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords (including vertebrates). The subphylum was at one time called Urochordata, and the term urochordates is still sometimes used for these animals. Despite their simple appearance and very different adult form, their close relationship to the vertebrates is certain. Both groups are chordates, as evidenced by the fact that during their mobile larval stage, tunicates possess a notochord, a hollow dorsal nerve cord, pharyngeal slits, post-anal tail, and an endostyle. They resemble a tadpole. Tunicates are the only chordates that have lost their myomeric segmentation, with the possible exception of the seriation of the gill slits. However, doliolids still display segmentation of the muscle bands. Some tunicates live as solitary individuals, but others replicate by budding and become colonies, each...

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