New Species of Sand-Hopper Found Living Inside Another Deep Sea Organism

Posted on February 28, 2014

A new species of sand-hopper was found living inside another deep sea organism. NIWA scientists discovered the sand-hopper species inside a bryozoan (also known as moss animals) between 500 and 1500 meters deep on the Chatham Rise, an area of ocean floor located to the east of New Zealand. The new discovery is the only known example of an amphipod species living inside a bryozoan. The new creature has been named Bryoconversor tutus. Tutus means safe and Bryoconversor means "living in Bryozoa."

Marine biologists Drs Dennis Gordon and Anne-Nina Loerz noticed the sand-hoppers inside a see-through layer on the bryozoans. The above image shows the side of a colony of the bryozoan showing adults (middle left arrow) and juveniles (upper right arrow) of the new species under a semi-transparent membrane. A close up of the new species is pictured below.

The scientists believe a female hopper makes a slit in the see-through layer on the back side of the bryozoan and enters the cavity beneath it, accompanied by a dwarf male. The slit repairs itself and the hoppers reproduce inside the bryozoan. When the bryozoan dies the amphipods leave and look for another bryozoan to colonize.

The scientists have not yet determined whether this relationship is beneficial to both the sand-hoppers and the bryozoan or whether it only benefits the sand-hoppers.

Dr. Gordon says, "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. We do know that the hopper is incapable of forming the membrane. Other bryozoans are known to have body cavities on their underside but they've never been seen before in this family. That's what is really weird and mysterious about it."

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