Ascidiacea

Taxonavigation

Kingdom: Animalia

Sub Kingdom: Eumetazoa

Super Phylum: Bilateria:Deuterostomia

Phylum: Chordata

Sub Phylum: Urochordata

Class: Ascidiacea

Order: Enterogona - Pleurogona

Introduction

Commonly referred to as Ascidians, Sea Squirts or Tunicates. A good thing to have living in a reef tank, they don't cause any problems with other organisms. Can be difficult to keep long term though, but typically are not added on purpose, just as organisms that have come on the liverock

Characteristics

Tunicates consist of a fleshy body with two openings; the inhalant and exhalant siphons. Water is passed through the body of the tunicate, via the siphons and food particles are filtered out. They come in many different shapes and sizes, and can sometimes be mistaken for sponges. Tunicates can live singly or in colonies. Majority that are seen in the aquarium hobby are fused to the rock or other substrate, but in the ocean colonies can be found floating in the open water.

Tunicates are chordates, which means they posses a notochord (like a primitive spinal column) during their early development, which consists of a larvae that looks a bit like a tadpole. The tadpole-like larvae find a suitable substrate to live on and "bite" it with their mouth. The larvae then fuses to the substrate, the notochord is lost and the physiology changes to assume the final morphology.