Tunicates of Zihuatanejo

SUBPHYLUM TUNICATA

-Sea Squirts (Class Ascidiacea)

-Order Aplousobranchia

-Family Diazonidae

-Genus Rhopalaea

(Rhopalaea birkelandi)

Rhopalaea birkelandi is a species of sea squirt (a type of tunicate) belonging to the family Diazonidae. Tunicates are marine invertebrates that filter-feed in ocean waters. Like other tunicates, Rhopalaea birkelandi has a sac-like body enclosed in a gelatinous outer tunic. It has two siphons—one for drawing in water (incurrent siphon) and another for expelling it (excurrent siphon). Commonly inhabits coral reefs, rocky substrates, or areas with strong water currents, where it can efficiently filter-feed on plankton and organic particles.

Description

• Rhopalaea birkelandi is a marine tunicate in the class Ascidiacea, subphylum Tunicata. Like other members of its genus, it is a sessile sea squirt with a sac-like body enclosed in a protective tunic. It attaches to submerged surfaces and has inhalant and exhalant siphons that circulate seawater through its body.

Range

• The distribution of Rhopalaea birkelandi is not fully established in readily available species accounts. It is native to Zihuatanejo, Guerrero, and the surrounding area.

Habitat

• It inhabits marine environments where it can attach to hard substrates, such as rocks, reef surfaces, and other submerged structures. Like other sea squirts, it is associated with coastal underwater habitats where water movement supplies food particles.

Diet

• Rhopalaea birkelandi is a filter feeder. It draws seawater through its inhalant siphon and captures bacteria, microscopic plankton, and suspended organic particles using a mucus-lined pharyngeal basket. Filtered water exits through the exhalant siphon.