Phallusia
Phallusia is a genus of tunicates, commonly known as sea squirts. These marine animals are filter feeders that belong to the family Phallusiidae and the class Ascidiacea. They are sessile, meaning they remain attached to a substrate for their entire life cycle. Phallusia species are distributed worldwide, inhabiting various marine environments.
Characteristics
Phallusia species are characterized by their sac-like bodies with two siphons: an incurrent siphon for water intake and an excurrent siphon for expelling water and waste. They are typically solitary, but some species can form colonies. Their bodies are covered by a tough outer tunic made of cellulose, which provides protection and structural support. They possess a simple nervous system and a heart that pumps blood through a closed circulatory system.
Habitat and Distribution
Phallusia species are found in a variety of marine environments, including rocky shores, coral reefs, and seagrass beds. They are typically found in shallow waters, but some species can live in deeper areas. Their distribution is widespread, ranging from the intertidal zone to the depths of the ocean.
Feeding and Reproduction
Phallusia species are filter feeders that rely on capturing small organisms and organic particles from the water column. Water is drawn into the incurrent siphon, passed through a filtering apparatus, and then expelled through the excurrent siphon. These animals reproduce both sexually and asexually. Sexual reproduction involves the release of eggs and sperm into the water column for fertilization. Asexual reproduction occurs through budding, where new individuals develop from the parent organism.
Taxonomy
The genus Phallusia includes several species, with the most common ones being:
- Phallusia mammillata
- Phallusia nigra
- Phallusia fumigata
These species are distinguished by their morphology, color, and habitat preferences.
References
For further information on Phallusia, refer to the following resources: