A fossilised sponge from New Zealand has been named as one of the top 10 new marine species of 2022.

Latrunculia (Latrunculia) tutu, more affectionately known as the Ballerina sponge, has a microskeleton that resembles the skirt of a ballerina.

Only recently discovered, the 35-million-year-old specimen has been selected out of 2000 newly described species for the World Register of Marine Species annual top 10 list.

Taxonomists Michelle Kelly and Carina Sim-Smith describe the sponge from a microfossil spicule - needle-like structures that sponges use as a structural skeleton and as a defence against predators - illustrated in a paper written in 1892 on the Oamaru Diatomite, or Oamaru Stone, by professors Hinde and Holmes at the British Museum.

"This tiny fossilised spicule was recovered from microfossil deposits in New Zealand's South Island (Oamaru). These spicules typically line the surface of the living sponge and are smaller than the width of a human hair. The illustrated spicule shows a wonderful structure with a pair of whorls around the middle like the bodice and skirt of a ballerina, and a small ring of spines at the top that resembles a crown," says Dr Sim-Smith.

"While it's only been found at one location in a fossilised form, many similar Latrunculia species are alive and well in New Zealand and Antarctica. Members of this group are often colourful, ranging from green to turquoise blue, purple or brown, and some even contain molecules with anticancer and antimicrobial properties."

The ballerina sponge was described by scientists from NIWA as part of their 2022 Biodiversity Memoir, an illustrated reference works that capture the study of New Zealand's distinctive marine fauna and flora.

Other species named in this year's list include the Satan's Mud Dragon, Japanese Retweet Mite, and Fluffy Sponge Crab.

The initial shortlist was chosen by a committee of volunteers to reflect the immense diversity of animal groups in the marine environment, including those notable for their interest to both science and the public.

The final decision was completed by public vote.