Conchoderma auritum

(Linnaeus, 1767)

rabbit-ear barnacle

Conchoderma auritum, commonly known as the rabbit-ear barnacle, is a pedunculate barnacle in the Lepadidae. It is primarily known as a whale-associated barnacle, attaching to the shells of other barnacle such as Coronula diadema on cetaceans. The species has also been documented on large pelagic fish including black marlin, representing a non-mammalian association. It possesses distinctive tubular ear-shaped structures on the capitulum and feeds using short, thick-segmented cirri adapted for strong currents.

Conchoderma auritum by (c) Cricket Raspet, some rights reserved (CC BY), uploaded by Cricket Raspet. Used under a CC-BY license.

Conchoderma auritum by (c) Ken-ichi Ueda, some rights reserved (CC BY). Used under a CC-BY license.

Pronunciation

How to pronounce Conchoderma auritum: /kɔnkoʊˈdɛrmaɪ ˈɔːrɪtəm/

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Identification

Distinguished from other Conchoderma by the paired tubular ear-shaped projections on the capitulum. Differs from Coronula diadema, with which it commonly co-occurs, by lacking the inflected, sharp-edged shell base with hollow coring tubes; instead, C. auritum attaches to the shell surfaces of Coronula rather than directly to skin.

Images

Habitat

Marine epipelagic zone, occurring on the external surfaces of large marine animals. Found attached to the shells of Coronula barnacles on cetaceans, and documented on large pelagic fish such as black marlin in the eastern Pacific.

Distribution

Recorded from Europe, Africa, New Zealand, Korea, and the Gulf of Tehuantepec, Mexico. Distribution is closely tied to the range of its mobile , particularly humpback whales and other cetaceans.

Diet

Feeds on large zooplankton captured using cirral appendages equipped with sharp, claw-like setae. The short, thick-segmented cirri are adapted for feeding in strong currents generated by movement.

Host Associations

Coronula diadema - substrateAttaches to shell surfaces of this barnacle on whales
Megaptera novaeangliae - humpback whale; of the Coronula substrate
Istiompax indica - black marlin; first documented non-mammalian

Behavior

Lives in clumps with mating group sizes reaching up to 26 individuals. Simultaneous . The ' attachment strategy involves settling on existing barnacle shells rather than direct tissue penetration.

Ecological Role

Commensal barnacle whose distribution and feeding are dependent on movement through plankton-rich waters. Facilitates studies of host patterns through its own geographic occurrence records.

Human Relevance

Serves as a biological indicator of distribution and movement patterns. Documented occurrence on sport-caught fish represents incidental observation rather than economic impact.

Similar Taxa

Conchoderma virgatumCo-occurs on fish ; differs in capitular lacking the prominent ear-shaped tubular structures
Coronula diademaFrequently found with C. auritum attached to its shell; distinguished by direct attachment to whale skin via coring tubes and different shell

More Details

Mating system

As simultaneous , individuals can mate with multiple neighbors; clumped living facilitates mating opportunities in the dispersed pelagic environment.

Feeding adaptation

The robust cirral with claw-like setae represents an to the high-flow environment created by swimming , contrasting with the finer filtering structures of sessile barnacles.