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You are here:   animal list > Philinopsis pilsbryi



Fact Sheet


Brief Summary

Physical Description


Color pattern


Local Distribution and Habitats

Biogeographical Distribution

Life History & Behaviour


Reproduction and Spawning


Evolution & Systematics

Fossil History

Systematics or Phylogenetics

Morphology and Physiology

External Morphology

Internal Anatomy

References & More Information



Names & Taxonomy

Common Names

Page Statistics


Feeding Strategy

As most of the Opisthobranch, Philinopsis pilsbyi is a highly specialized predator. It feeds on other invertebrates that produce toxins, in order to transform them and use them to create its toxic mucus (Thompson 1960). However, as the feeding process of Philinopsis p. has never been observed, the prey preference are still unclear. Gosliner (1987) suggested that Philinopsis p. feeds on flatworms, while Marshall & William (1999) presumed they were feeding on polychaetes worm.

Physical and Mechanical Defense

Reduction and internalisation of the shell in Philinopsis p. implies other defensive strategies. Shell reduction within molluscs is uncommon, and occurs mainly in the highly mobile cephalopods. Philinopsis p. has glandular structures able to create a toxic mucus to compensate the absence of an external shell (Marin & Ros 2004). 

Moreover, this opisthobranch probably uses his coloration as a signal for predators to aware them of his toxicity (e. g. Figure 1). This process is called aposematism and is defined as the use of conspicuous colouration to warn predators that an individual is chemically or otherwise defended (Poulton, 1890; Cott, 1940). A comparative analysis held by Cortesi & Cheney (2010) already proved that there is a significant correlation between conspicuousness and toxicity, indicating that conspicuousness acts as an honest signal when signifying level of defence and provides evidence for aposematism in opisthobranchs.It has also been confirmed that several species of opishtobranch are very toxic, and lead to death when eaten by fishes (Thompson 1960).

Figure 1: Coloration of an adult Philinopsis on coral (Picture Alice C.)

Locomotion performance

The soft body of the Philinopsis Pilsbryi allow him to move easily on sand and corals. But a particular attribute that this opisthobranch has developped is its capacity to burrow in any type of sand.

Video: Burrowing process on Philinopsis Pilsbryi, accelerated 16x (Video by Alice C.)

As it is demonstrated on this video, Philinopsis Pilsbryi is not only using his mucus to defend himself, but also uses it to burrow in the sand. As soon as the animal starts the burrowing process, it immediately starts creating a mucus that helps covering its body with sand, without necessarily going to deep in the sand.