Photo of the day (58): Pleurobranchus areolatus

Pleurobranchus areolatus is a sea slug from the family Pleurobranchidae.

It lives in Caribbean Sea, Brazil, Madeira and Canary Islands. Such distribution in western Atlantic and also in eastern Atlantic is called amphiatlantic (or amphi-Atlantic).

I thank my colleague Jessica Goodheart from the USA who kindly provided the photo.

This certain specimen of Pleurobranchus areolatus comes from Panama. You can find more information about sea slugs from Panama in her article “Identification guide to the heterobranch sea slugs (Mollusca: Gastropoda) from Bocas del Toro, Panama“.

This is the right side view of the slug. Its body is oval. There are numerous tubercles on the dorsum. Its rhinophores are in the frontal sinus. The gill is not visible because it is under the dorsum. There is also small internal shell inside the slug’s body, but the shell is not visible externally.

Pleurobranchus areolatus

Pleurobranchus areolatus from Panama by Jessica Goodheart, CC-BY-4.0

References

Goodheart J. A., Ellingson R. A., Vital X. G., Galvão Filho H. C., McCarthy J. B., Medrano S. M., Bhave V. J., García-Méndez K., Jiménez L. M., López G. & Hoover C. A. (2016). “Identification guide to the heterobranch sea slugs (Mollusca: Gastropoda) from Bocas del Toro, Panama“. Marine Biodiversity Records 9(1), p.56. doi:10.1186/s41200-016-0048-z

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Photo of the day (57): Daudebardia rufa

Daudebardia rufa is a carnivorous semi-slug. It belong to the subfamily Daudebardiinae within the family Oxychilidae or it can be classified in a separate family Daudebardiidae.

They are uncommon, because they can not live in highly altered forest monocultures. They require sufficiently humid forests with enough leaf litter, logs and fallen wood. There should be enough prey such as earthworms and snails. Humid habitat is necessary, because they have no shell large enough to protect them against droughts. My Daudebardia rufa comes from Moravia, the Czech Republic.

The right side view looks like this. The large muscular body has some tubercles. There is visible a pneumostome (breathing pore) bellow the shell. The body length of this specimen is 17 mm.
Daudebardia rufaThe shell looks like this:
Daudebardia rufaReferences

no references

Photo of the day (56): Umbraculum umbraculum

Umbraculum umbraculum is quite large marine gastropod. It belong to the family Umbraculidae. It can grow up to 15 or 20 cm. The color may vary from yellow to brown or to red.

There are two populations worldwide. One population in Indo-West Pacific region and one population in east Atlantic and Mediterranean region. The later one was considered as a separate species Umbraculum mediterraneum. They are considered synonymous although there exist no review of the genus yet. My Umbraculum comes from Croatia and I have take following photos ex situ.

The shell is much smaller than the animal body. The shape of the shell is cap like or limpet like. The tip of the shell seems to be pointing in some direction sometimes, but the tip does not allow to identify the head region if the animal is retracted. The shell is always covered with some growths.

Umbraculum umbraculumThere are many tubercles on its mantle. Detail of tubercles:

Umbraculum umbraculumFoot is also circular even when the animal is crawling:
Umbraculum umbraculumThere is a gill on the right side of the body just below the shell. There are visible lamellae of the gill under the shell.
Umbraculum umbraculumIts dark eyes are between tentacles (rhinophores).
Umbraculum umbraculumI was no lucky to get a proper photo of its frontal slit region, that contain mouth and permanently protruded penis. Maybe next one.

Umbraculum umbraculum feeds on sponges (Porifera) from the class Demospongiae. Yes, SpongeBob should be afraid of this snail beast! Other ones can enjoy this snail species, because it certainly awaits for further interesting discoveries.

References

Rudman W. B., (1999 January 14) Umbraculum mediterraneum (Lamarck, 1819). Sea Slug Forum. Australian Museum, Sydney. accessed 2016 October 14.

Rudman W. B., (1999 March 7) Umbraculum umbraculum (Lightfoot, 1786). Sea Slug Forum. Australian Museum, Sydney. accessed 2016 October 14.