Hairy Spiny Doris, Thorny Doris – Acanthodoris pilosa

The Hairy Spiny Doris, also known as the Thorny Doris, is a fascinating species of sea slug scientifically classified as Acanthodoris pilosa. This colorful nudibranch is a captivating example of the diversity found in the marine world.

Description & Characteristics

Acanthodoris pilosa, true to its name, is a relatively small nudibranch with a maximum size of around 25 mm. Its body is typically a vibrant orange-red color, often speckled with white spots. The defining characteristic of this species is its distinctive covering of hair-like cerata, giving it a distinctly hairy appearance. These cerata, which are finger-like projections on the back, are covered in spines, further contributing to its “thorny” moniker.

Habitat and Occurrence

The Hairy Spiny Doris, Acanthodoris pilosa, is a common sight in coastal waters, particularly in fjords, the intertidal zone, and tidal zones. It can also be found in mudflats and the Wadden Sea, showcasing its adaptability to diverse environments. Acanthodoris pilosa is often found on stony soils, where it can readily access its primary food source. These environments provide a suitable habitat for this species to thrive and reproduce, making it a regular inhabitant of these marine zones.

Taxonomy

The species Acanthodoris pilosa belongs to the Class: Gastropoda, Order: Nudibranchia, and Family: Onchidorididae. This classification places it within the larger group of gastropods, specifically the diverse and often strikingly colorful group of nudibranchs, known for their lack of a shell. The Onchidorididae family is characterized by its members possessing a broad body, often with prominent cerata.

Feeding

Acanthodoris pilosa is a carnivore, with a specialized diet consisting of bryozoans, also known as sea mats. These tiny, colonial animals provide a consistent food source for Acanthodoris pilosa, allowing it to flourish in environments where bryozoans are abundant. This specialization in diet highlights the intricate relationships and dependencies that exist within the marine ecosystem.