Newly discovered sandhopper (Bryoconversor tutus) mother (middle left arrow) and juveniles (upper right arrow) living in the transparent membrane of its host. Inset: a close-up of the sandhopper. Photo supplied.
Is a newly discovered sandhopper the biggest freeloader in
the ocean or is it a better guest than the fish that hides
inside a sea cucumber?
Niwa marine biologist Dr Dennis Gordon, of Wellington, has
discovered a new species of sandhopper.
He believes the female sandhopper makes a slit in the
backside of another deep-sea organism - a bryozoan species
that lives deep in the Chatham Rise, in the Pacific Ocean
east of the South Island - and enters with a dwarf male, to
breed and live inside the host with its family.
The slit on the host repairs and the hoppers live inside
until the host dies. The hoppers then leave to colonise
The hoppers are up to 1cm long and have been discovered
living inside bryozoa up to 5cm long.
Dr Gordon was unsure if the hoppers living protected in a
transparent membrane cavity of the host were a welcome guest
The hoppers and the bryozoa could benefit or the hoppers
could be the sole beneficiaries, taking nutrients and
protection from their host, Dr Gordon said.
''We are also wondering if there is a two-way nutrient flow
whereby the secretions of the hopper can be transferred to
the bryozoan, but we don't really know.''
To reveal more on the relationship, live specimens needed to
be collected, which was difficult when they lived at a depth
of between 500m and 1500m.
Dr Gordon said many animals had unusual relationships,
including a fish that lived in the rectum of a sea cucumber
in the Caribbean.
The fish used the rectum to shelter from its enemies, he
''It doesn't bother the sea cucumber but I don't think it
gains anything either.''
The new sandhopper was called Bryoconversor tutus.
More samples of the sandhoppers would be collected for
further DNA testing, Dr Gordon said.