There are 2,300 species of ascidians and three main types: solitary ascidians, social ascidians that form clumped communities by attaching at their bases, and compound ascidians that consist of many small individuals (each individual is called a zooid) forming colonies up to several meters in diameter.
Hai 2.300 especies de ascidiáceos de tres tipos principais: ascidiáceos solitarios, ascidiáceos sociais, que forman comunidades agrupadas ao adherirse polas súas bases, e ascidiáceos compostos, que constan de moitos pequenos individuos (cada individuo denomínase zooide), que forman colonias de ata varios metros de diámetro.