Every year, we discover so many wonderful new species of plants and animals. In 2023, almost 2000 new marine species were added to the World Register of Marine Species (WoRMS), a comprehensive list of all the marine plants, animals, and other marine life that we know exist (or, in the case of fossils, once existed).

Is it possible to pick a favourite discovery? The taxonomists - people that specialise in identifying species - that contribute to to WoRMS say yes! So, without further ado and in no particular order, here’s their top ten new marine species from 2023.

The Bifrost Nemertean

Reaching over 20 centimetres in length, this beautiful marine worm was spotted in the Caribbean. The bright colours warn potential predators that it is highly toxic.

They live in shallow coastal waters where they can hide in coral rubble, gravel, and other nooks and crannies.

The Samoan Nautilus

This is one of just three new species of nautilus described by taxonomists. Considering that we only knew of three species previously, that’s quite an achievement!
This particular nautilus was spotted near Pago Pago, American Samoa, between 200 and 400 metres depth.

Solwarawarriors Vestimentiferan

If you want to spot this marine worm for yourself, you’ll have to go deep…really deep. It was spotted in the hydrothermal vent fields in the Manus Basin of the Bismarck Sea.

The name Solwarawarriors was given in honour of the Alliance of Solwara Warriors, a coalition of communities from Papua New Guinea, and islands in the Solomon and Bismarck Sea, are working to protect deep sea ecosystems and the cultural and environmental heritage of people in the region through advocacy, education, and partnership.

St. George's Cross Medusa

This beautiful jellyfish was first spotted 800 metres down in the Sumisu Caldera, which lies off the Ogasawara Islands, Japan, in 2002. In 2020, researchers managed to capture one to study.

Not only is this jellyfish a new species, it represents a new subfamily of jellyfish - a group of related species.

Fordyce’s Giant Penguin

If you’re wondering why the image is an illustration rather than a photograph, its because this penguin is an ex-penguin.

Fordyce’s Giant Penguin lived about 60 million years ago. Weighing an estimate 150 kilograms, it’s considerably bigger than the largest penguin that lives today - the emperor penguin, which weights a measly 22 - 45 kilograms.

Falkor’s Carnivorous Sponge

You might think that the Great Barrier Reef has been so well studied there isn’t much we don’t know about it and the species that live there. Yet, an exploration of the Great Barrier Reef's deep reefs uncovered this - and two other species of carnivorous worm.

The name Falkor was given in honour of the Research Vessel Falkor, which is operated by the Schmidt Ocean Institute. It has been instrumental in a lot of ocean discoveries.

Fine Line Nudibranch

This beauty was spotted in the mesophotic zone - the part of the ocean where it becomes deep enough that starts to become dark.

The black and white patterns serve as a warning to predators that this unassuming little sea slug may not be the tasty treat it appears.

Hannan’s Pygmy Squid

When you see the word “pygmy” in a species’ name, you know it will be small. This squid is less than a centimetre in length, but that doesn’t mean it spends its time hiding from danger.

Recreational divers taking the plunge in Ryukyu Islands, Japan, at night reported these tiny squid would swim out towards their dive torches, arms and tentacles stretched out.

In fact, recreational divers have been able to provide lots of information about this beautifully brave little squid.

Prince Albert’s Sea Daisy

I know it doesn’t look like it, but this is a starfish, also known as a sea star.

Prince Albert’s Sea Daisy is just one of four known species of sea daisy.

We only discovered this particular species thanks to genetic sequencing. If you want to spot one, head out to the Pacific East Coast, between Canada and Costa Rica, and look for some sunken wood. If you had an ROV, you could also take a look at some hydrothermal vent worms - another place they like to hang out.

Bouchet’s Dorymenia

Another species that isn’t quite what it looks like. Bouchet’s Dorymenia is not a worm, but a mollusc (snails, scallops, and so on).
Their body is covered in spiny spicules - hard structures that when meshed together, can act like a skeleton. They’re notoriously difficult to spot because they’re tiny and like to live in deep sea mud.