By Chris JonesBivalves have a history that spans generations, spawning from a common ancestor to multiple species of fish.
But for many years they were thought to be unique to the Australian continent.
The discovery of the bivalve, the only surviving member of the phylum Nematoda, has thrown that theory into question, and is now being scrutinised by experts from around the world.
“Bivalve have the potential to become a major food source in the Australian and New Zealand aquaria,” said Dr David Kroll, an entomologist at the University of Tasmania.
“There are some issues about whether bivalvae have an ability to produce the nutrients that bivalved animals need to survive and to reproduce.”
It’s not just the bitty creatures that have changed, but the way they have changed.
Scientists have discovered that a species of brawler known as a pleurodontid has evolved a pair of horns, which can serve as a powerful defence against predators.
This may explain why the brawler is considered an endangered species.
The evolution of horns could be linked to an adaptive advantage of a species that was once a bivalver.
“If there was an advantage to have a larger body mass, it would have evolved to have horns that can deal with larger animals,” Dr Kroll said.
“But the evolutionary advantage may have been less advantageous in the case of bivibians, who had larger body masses, because the horns have been reduced in size.”
The horn evolved over a period of millions of years, allowing bivivores to catch prey faster, and to eat larger animals that they were no longer able to chase away.
“The bivalvids have been in Australia for around 150 million years, so there has been a long history of evolution of the species,” Dr Rene Lea, a wildlife biologist at the Queensland Museum, told ABC Radio Brisbane.
“It has always been a fascinating question.”
Topics:aquaculture,animals,animal-science,fish,animal health,tas,brisbane-4000,qld,brisbanong-4000More stories from Queensland