Larva Evolutionary theory Origin of vertebrates
Tunicates are sessile, but their larvae are mobile, and have some features found in early vertebrates. The process of paedomorphosis, where juvenile features are retained in the adult, is the proposed mechanism. Garstang, Walter 1894. Embryos and ancestors'. 3rd ed, Oxfor, The evolution of chordates, p76. Genome analysis does show that the tunicates are the closest living relatives of vertebrates.