Brown Horned Dorid, Cedar-Scented Dorid – Acanthodoris brunnea

The Brown Horned Dorid, Cedar-Scented Dorid (scientific name: Acanthodoris brunnea) is a species of sea slug, a type of nudibranch, known for its distinctive appearance and pungent scent.

Description & Characteristics

Acanthodoris brunnea is characterized by its brown to reddish-brown coloration, often with a subtle orange hue. The body is typically smooth and oval-shaped, reaching a maximum size of approximately 3 cm in length. A prominent feature of this species is the presence of two prominent “horns” or rhinophores on the head, which are sensory organs used to detect food and other stimuli. These rhinophores are usually orange in color and distinctly contrast with the brown body. The gills of Acanthodoris brunnea are located on the back of the animal and are often feathery and white in color.

Habitat and Occurrence

The Brown Horned Dorid, Cedar-Scented Dorid is typically found in the intertidal and shallow subtidal zones, typically at depths ranging from 0 to 30 meters. These areas include rocky shores, tide pools, and kelp forests. The species is prevalent in the northeastern Pacific Ocean, including areas along the coast of California, Oregon, Washington, and British Columbia.

Taxonomy

Acanthodoris brunnea belongs to the class Gastropoda, which encompasses a vast array of mollusks including snails, slugs, and sea butterflies. It is further classified within the order Nudibranchia, commonly known as sea slugs, which are characterized by their lack of external shell and often vibrant coloration. The species is a member of the family Onchidorididae, which includes a number of small, often cryptic nudibranchs that are frequently found in intertidal and shallow subtidal habitats.

Feeding

The Brown Horned Dorid, Cedar-Scented Dorid (Acanthodoris brunnea) is a specialist feeder, relying on a diet consisting primarily of bryozoans, also known as sea mats. These colonial invertebrates are often found encrusting rocks and other surfaces in the intertidal and shallow subtidal zones, providing a readily available food source for Acanthodoris brunnea. The nudibranch’s sharp, radula, a rasping tongue-like structure, allows it to efficiently scrape and consume bryozoans.