Seen one of these predatory worms?

A University of Otago masters student is appealing for sightings of a carnivorous worm that sucks out the innards of its prey, a creature he says could be living in many Dunedin residents' backyards.

Dan Barrett, who came from Oregon in the United States to study towards a masters degree in wildlife management, wants people living in Dunedin to contact him if they see the rare peripatus worm, to help give him a better idea of where in the city they live.

The peripatus is a 500-million-year-old species often called a "living fossil" and the "missing link" between worms and legged arthropods.

"They are a bizarre throwback to prehistoric life ... they haven't changed a lot since prehistoric times," Mr Barrett said.

The worm, which has an average length of 30mm, kills its prey by rearing up on its haunches and shooting a stream of a glue-like substance which disables its victim. It then injects saliva to dissolve its prey's innards and sucks out the resulting meal, which it feeds on at its leisure.

They normally lived in damp dark places, but had been found in some "unusual" places, he said.

One person who responded to an advertisement he put in The Star last week found one under a wheelie bin in Lookout Point.

"He was looking for worms to use for fishing and found peripatus under [the bin]," he said.

Once completed, Mr Barrett's findings could be used to help conserve the unique species.

Mr Barrett said he first became interested in studying peripatus last September when he read about the fact they were living on land to be used as part of the Caversham Valley highway expansion.

After doing a bit of reading he decided to do his masters degree on the worm, starting in February.

Since beginning field work in April, he had spent between 30 and 35 days in a Dunedin reserve looking for them and then recording information, such as soil moisture levels, soil temperature and the direction of slope where they were found, to determine what type of conditions they preferred.

He had about 20 more days of field research to go and hoped to have this finished by July.

He got a lot of "dirty looks" from people when walking home with mud all over his clothes after a day looking for peripatus in the soil and undergrowth.

"I look like a bit of a bum at the end of the day," he explained.

• If anyone would like to contact Dan, his email address is barda976@student.otago.ac.nz