The Agassiz’s Sidegill, scientifically known as Berthella agassizii, is a fascinating marine gastropod belonging to the family Pleurobranchidae. This species is recognized for its distinctive sidegill, a prominent respiratory organ located on the right side of its body.
Description & Characteristics
Berthella agassizii typically reaches a maximum size of 50 mm. Its body is elongated and oval-shaped, with a prominent hump on the dorsal side. The mantle, a protective covering over the internal organs, is smooth and often covered in small, irregular bumps. The Agassiz’s Sidegill exhibits a wide range of colors, from tan to orange, brown, and even greenish hues. This color variation can often be attributed to the type of algae or sponges that the animal may consume.
Habitat and Occurrence
The Agassiz’s Sidegill prefers coastal waters, particularly rocky shores and rock coasts, and can be found in both shallow and deeper environments. Its habitat range extends from the lower limit of the intertidal zone to the shelf edge, reaching depths of approximately 200 meters. This makes Berthella agassizii a common inhabitant of the subtidal, sublittoral, and infralittoral zones, which collectively constitute the neritic marine environment.
Taxonomy
Berthella agassizii belongs to the Class Gastropoda, which encompasses a vast array of mollusks. Within this class, it is further classified under the Order Pleurobranchida, a group characterized by their unique gill structure and lack of a shell. The family Pleurobranchidae comprises several species of sea slugs, all possessing similar physical attributes.
Feeding
Berthella agassizii is a food specialist, relying primarily on sea squirts as its dietary source. These sessile organisms are typically found attached to rocks and other submerged surfaces, providing a readily available food source for the Agassiz’s Sidegill.
Image References