Life Science Noteworthy SERIES: Invertebrate of the Week

Invertebrate of the Week #16 – Peltodoris atromaculata

Peltodoris atromaculata
Peltodoris atromaculata. Source:

This week we are highlighting the distinctive nudibranch Peltodoris atromaculata.

A southern European species, this spotted Discodorid sea slug can be found throughout the Mediterranean and select locations off the western coast of Europe, including the Asturias, the Canary islands, Açores, Madeira, and the Strait of Gibraltar.

Inhabiting low-light rocky reef environments, Peltodoris atromaculata has a penchant for chewing on Petrosia ficiformes sponges. Once attached, the nudibranch may remain there for a couple of days, gradually scraping away areas of the sponges’ surface.

Peltodoris atromaculata
Peltodoris atromaculata. Photo: MassimoCapodicasa

The striking coloration of Peltodoris atromaculata has earned it the nicknames “leopard slug” and “swiss cow”. Such conspicuous coloration implies, perhaps, an aposematic approach to predator deterrence and research seems to back up that assumption. Peltodoris atromaculata is capable of sequesters toxic compounds derived from its sponge prey.

Couple that with a mantle buttressed by calcareous skin spicules and it’s clear that this little nudibranch is not to be trifled with.

Being dorid nudibranches, Peltodoris atromaculata breathe via a “naked gill” plume on their backs. Known as branchial plumes, these structures are composed of fully retractible gills oriented about a central axis.

Peltodoris atromaculata branchial plume
Peltodoris atromaculata branchial plume. Photo: Phillipe Guillaume
Peltodoris atromaculata
Peltodoris atromaculata. Source:

Further Reading

%d bloggers like this: