Bivalve Pulvinitidae

Animals belonging to the bivalve family Pulvinitidae were originally known only from fossil records dating back millions of years ago.

So it was somewhat of a surprise in 1913 when some Pulvinitid specimens were trawled from a depth of 180-460 m off the eastern coast of Victoria, by the Commonwealth Fisheries Research Vessel 'Endeavour'. Although only dead shells, they were obviously of recent origin and were named Foramelina exempla by the Australian Museum curator at the time, Charles Hedley.

No further specimens were found for over 60 years. Then in 1980, a couple of Pulvinitidae shells were brought up from a depth of 400-460 m off the coast of Sydney by commercial trawlers. This discovery was closely followed in July 1981 by a jackpot find - a whole aeroplane wing with living specimens attached, trawled from a depth of 406m also off the coast of Sydney .

This last find generated a number of intriguing questions - What was an aeroplane wing doing on the bottom of the sea floor? Why were these rarely collected animals found on a constructed object and nowhere else? Where did they live naturally?

The first question was easy - after World War II, surplus military equipment was dumped in deep waters out to sea beyond the reach of the commercial fishing of the time. Within 35 years however, with the improvement of fishing technology, Australian trawlers were regularly working at these depths. Trawlers began to come across the dumped equipment often tearing their trawl nets on it.

Fortunately in this case, the skipper with the ripped nets did not immediately throw the offending junk back overboard, but brought it back into port and contacted a shell collector about the animals living on the wing. When the collector realised that he did not recognise the bivalves, he contacted the Australian Museum. As a result, the first known living specimens of the Pulvinitidae family made their way to the Australian Museum in good condition.

The next two questions took longer to answer. In 1997, underwater video showed live Pulvinitids attached to steep rock walls at a depth of 150- 285 m in Fiordland, New Zealand. Trawlers generally avoid steep rocky areas, explaining why virtually no specimens had appeared in commercial or research trawls. The plane wing was just in the right place at the right time providing a suitably hard surface for the animals to attach to.

In 1984, T Palmer revised the Pulvinitidae family after the new discoveries and moved the dead specimens from the 'Endeavor' to the fossil genus Pulvinites .