A new shrimp species smaller than a child's fingernail has been discovered in a London museum.

Heteromysis hornimani has been at the Horniman museum for 12 years, but its uniqueness was only discovered by chance.

The mysid shrimp is thought to have hitched a ride to the museum on Fijian ocean rock brought in for use in an aquarium. Only when the call came out from Daniel Abed-Navandi, a marine biologist at the University of Vienna, for shrimp samples to survey, did its significance become apparent.

The Horniman's Deputy Aquarium Curator Michelle Calvert told CGTN Europe the species has two standout features – its fast, zig-zagging, swimming style and a brood pouch in females, from inside which they give birth to fully formed infants. The latter feature distinguishes mysid shrimps – small crustaceans found in both the sea and in freshwater – from the more common variety.

READ MORE:
Anxiety surge over life after lockdown
 

Seville's oranges are key to green future
 

PODCAST: Are we alone in the universe?
 

According to Calvert: "These tiny mysid shrimps are literally only about 3 millimeters big. Their eggs develop in the brood pouch, which release fully formed tiny shrimps. They're very fast at swimming and have this unique 'figure of eight' swimming style."

Calvert added: "They are bottom-dwellers and look for scraps, eating zooplankton and phytoplankton, any detritus on the bottom."

The shrimps were originally used as food for aquarium fish at the museum, which houses 350,000 objects covering anthropology, natural history and musical instruments.

"At the moment, we've stopped using them as food, but they are ideal for fussy feeders that come in and need some help being weaned on to frozen food," explained Calvert.

Reaching sexual maturity in 12 to 20 days, Heteromysis hornimani is a voracious breeder, meaning they will soon be back on the fishes' menu, despite plans to show off the species when the museum reopens on May 17.

"It's a lovely story to tell but we won't have a display dedicated to them as they are very small and very cryptic," said Calvert.

The species has been named after the museum's founder. "We're so proud that Frederick Horniman is being represented. His vision was to bring the world to Forest Hill and connect nature with people. So now we're bringing the Horniman shrimp to the world."

A sample of the species has been preserved in ethanol at the Vienna Natural History Museum, as "the type specimen."

Scientists estimate there are around 8.7 million species of plants and animals in existence, but just 1.2 million species identified and described. With 91 percent of marine species remaining undiscovered, marine biologists hope Heteromysis hornimani will be one of many shrimp species revealed in the coming years.