Trididemnum opacum is a colonial tunicate, a type of marine invertebrate, belonging to the family Didemnidae. These colonies are often found in various marine environments, contributing to the biodiversity of these ecosystems.
Description & Characteristics
Trididemnum opacum forms colonies that are typically encrusting, meaning they grow over surfaces. These colonies can be quite extensive and may appear as a thin, gelatinous sheet. They are typically a pale yellow to white color, contributing to their common name of “opacum,” which means opaque. The individual zooids, which are the tiny animals that make up the colony, are typically small, measuring only a few millimeters in length. Each zooid has a siphonal opening for feeding and another for expelling waste. The colony can reach sizes of up to several centimeters across, depending on the conditions of their environment.
Habitat and Occurrence
Trididemnum opacum is typically found in shallow, intertidal zones, making it a prevalent presence in these aquatic ecosystems. They can often be found growing on a variety of surfaces, including rocks, shells, and seaweed. While they primarily inhabit the intertidal zone, they can also be found in slightly deeper waters, typically within the infralittoral zone, which extends down to about 40 meters in depth. Their presence across these zones highlights their adaptability to various conditions within these coastal marine environments.
Taxonomy
Trididemnum opacum belongs to the Class Ascidiacea, a group of marine invertebrates that are commonly referred to as sea squirts. Within this class, it is further classified under the Order Aplousobranchia, which includes a diverse range of colonial ascidians. Finally, it is a member of the Family Didemnidae, a group known for their encrusting colonial growth forms and often vibrant colors.
Feeding
Like many other tunicates, Trididemnum opacum is a filter feeder. It uses its siphons to draw in water, filtering out microscopic food particles like phytoplankton and zooplankton. This feeding strategy allows them to thrive in environments rich in plankton, contributing to the flow of energy within marine ecosystems.
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