The council issued a statement yesterday touting the find early this year in the Akatore Creek estuary, 50km south of the city.
The up to 8mm, air-breathing, shell-less mollusk is one of several types known as Smeagol, named after the character first introduced in J.R.R. Tolkien’s The Hobbit, later named Gollum.
Council freshwater ecologist Ciaran Campbell said the tiny animal, also known as a "gravel maggot", had a lifestyle similar to the fantasy character, "living below light-deprived gravel beach surfaces".
It was exciting to find the little-known creature in Otago, he said.
"While they’re small and unassuming creatures, Smeagol likely plays a role in recycling nutrients from beach-cast kelp back into the thriving ecosystems of the surrounding oceans."
Smeagol species were found in Wellington, Marlborough and the West Coast as well as Tasmania, New South Wales and Phillip Island in Australia, the council said.
Council biodiversity senior environmental technician Matt Salmon said the sandy silty habitat at Akatore estuary where the Smeagol was found was different from where it had been found previously.
The environmental DNA, or eDNA, sampling that found the animal also detected a genetic signature "slightly different" from others and so it could potentially be a new species, he said.
Under the New Zealand threat classification system two species of gravel maggots — Smeagol climoi and Smeagol manneringi — are listed as nationally critical, the same threat status as better-known endangered animals such as kākāpō, long-tailed bats and Māui dolphins.
