Monterey Bay Aquarium Research Institute scientists have discovered Bathydevius caudactylus, a new species of glowing sea slug that lives deep in the ocean.

This method of protection can keep almost all predators at bay - but not the kaleidoscopically colourful sea slug. Nudibranchs, commonly known as sea slugs, are a group of shell-less marine molluscs.

There are spectacular deep-sea nudibranchs as well. Here is a new species of Dendronotus, collected in 2013 and found feeding on hydroids at a methane seep off California. Frenulates are extraordinary ...