The slugs that we find in the garden are not the most inspiring creatures. They kind of just look like dark, slimy blobs.

But deep under the sea, their relatives are quite the opposite. And one particular group of sea slugs, called the nudibranchs (pronounced "nood-i-branks"), are especially gaudy looking.

These bizarre-looking creatures are covered in bright and vibrant colours, with psychedelic patterns strewn across their gills, which, in turn, can come in a variety of shapes, from mohawks to shag rugs.

Yet even though nudibranchs live in virtually all the world's oceans, from the darkest depths to the transparent shallows, they are still poorly understood and very little research on them has been done.

Until recently, in fact, we knew of only three deep-water species in the entire Northeast Pacific.

But now, thanks to marine biologists at California Polytechnical Institute in Pomona and the Scripps Institution of Oceanography, we have found nearly double that number living off the US west coast.

These scientist have recently described five new species of nudibranchs that live on the deep seafloor off the coast of California and Mexico, and their strange beauty is a sight to behold.

Tritonia nigritigris

Tritonia nigritigris 4 640(MBARI)

Dendronotus claguei

Dendronotus claguei 1 640(MBARI)

Ziminella vrijenhoeki

Z vrijenhoeki labfield 640(Nerida Wilson & Greg Rouse)

Aeolidia libitinaria

A libitinaria labfield 640(Greg Rouse)

Cuthona methana

C methana lab 640(Nerida Wilson & Greg Rouse)

This study has been published in Zootaxa.