The beautiful sea slug

Name: Phyllodesmium acanthorhinum

Location: Off the coast of Japan

What is it: A colourful sea slug

Why it made the list: Not know for their beauty, this sea slug stands out for its striking good looks. It is a 'missing link' between sea slugs that feed on hydroids and those specializing on corals.

Gastropods do not get more photogenic than sea slugs whose graceful lines and vivid coloration make them beauties of the deep.

This new species, which photographs in shades of blue, red and gold, also contributed to a better understanding of the origin of an unusual symbiosis in other species of the genus. Related sea slugs have multi-branched guts in which algae called zooanthellae live.

These algae have a primary symbiotic relationship with the corals on which the sea slugs feed. Once sequestered in the gut, the photosynthetic algae produce nutrients of benefit to the host. The newly identified species is an inch long, more or less (17-28 mm), and resides in the Japanese islands.

This colourful new species of sea slug shows up red, blue and cold when its almost translucent body is photographed. It is considered to be a missing link between sea slugs that feed on corals and those that feed on hydroids - small predators related to jellyfish