An evolutionary war that raged beneath the sea more than 100 million years ago created the octopus and squid, new research has shown.
(From New Scientist)– Cephalopods – the tentacled creatures that include octopuses, squid and cuttlefish – possess some extraordinary traits such as instantaneous colour changing, ink squirting, jet propulsion and polarised vision.
Octopuses are also known to be highly intelligent for invertebrates and display an ability to solve complex problems.
Until now the origins of cephalopods, which evolved from ancient marine molluscs with shells, have been shrouded in mystery.
The new research from scientists at the University of Bristol, in the UK, suggests that the octopus and its relatives developed their bizarre body plans and unusual abilities during a period of upheaval beneath the waves known as the Mesozoic Marine Revolution.
“On land this was the time of the dinosaurs, but beneath the seas, ecologies were changing rapidly,” says lead researcher Al Tanner. “The cephalopods are now known to have also been caught up in this major transition, evolving to lose the shells of their ancestors and develop as dynamic and uniquely adapted marine animals.”
“Fish, squid and their predators were locked in evolutionary ‘arms-races’, leading to increasingly speedy and agile predators and prey,” says Tanner.
The team compared specimens from the fossil record with evolutionary history chronicled in DNA.
A “molecular clock” technique, based on the rate at which DNA mutates naturally, was used to determine when different groups split away from each other.