Duck barnacle

Description:

The main characteristic of Lepas anatifera is its heart-shaped bivalve shell, called a capitulum, that can grow up to 5 cm in length and surrounds the body and limbs. The capitulum is composed of five striated, glossy white, calcareous plates. The first pair of calcareous plates are located at the aperture and the end of the peduncle. The second pair is more distal, located near the aperture. The fifth plate, the carina, creates a spine that connects all the valves to one another. The capitular valve allows extrusion and extraction of six food-catching tentacular structures called cirri. The barnacle attaches to objects using its stalk or peduncle, which ranges in length from 4-90 cm. The peduncle is a part of the head and is attached by a basal disc and covered by a tough cuticle that is unarmored and flexible. Beneath the cuticle lie longitudinal muscles. Attachment is maintained with cement produced from the glands of the peduncle.

Habitat:

These were on a red bulb found washed up by the surf.

Notes:

Lepas anatifera is a pelagic barnacle that can be found attached to a variety of floating objects, including driftwood, bottles, boats, buoys, macroalgal rafts, and turtles. It can also be found on fixed objects such as rocks and off-shore structures. This species is most abundant in tropical and subtropical waters where sea temperatures exceed 18-20 ºC. (Castro, et al., 1999; NOBANIS, 2008; Patel, 1959)