Museum Victoria palaeobiologist Dr Erich Fitzgerald has made groundbreaking discoveries into the origin of baleen whales, based on a 25-million-year-old fossil found near Torquay in Victoria, Australia.

Dr Fitzgerald's study, which is published in the Zoological Journal of the Linnean Society, is centred on Mammalodon colliveri, a primitive toothed baleen whale, one of a group of whales that includes the largest animal ever to have lived, the blue whale.

"Through study of Mammalodon, I hypothesise that it was a bottom-feeding mud-sucker that may have used its tongue and short, blunt snout to suck small prey from sand and mud on the seafloor. This indicates early and varied experimentation in the evolution of baleen whales," explained Dr Fitzgerald.

The research conducted by Dr Fitzgerald supports Charles Darwin's speculation in The Origin of Species, that some of the earliest baleen whales may have been suction feeders, and that their mud grubbing served as a precursor to the filter feeding of today's giants of the deep.

Although Mammalodon had a total body length of about 3 metres, it was a bizarre early offshoot from the lineage leading to the 30 metre long blue whale. The new research shows that Mammalodon is a dwarf, having evolved into a relatively tiny form from larger ancestors.

"Fossil skull of the whale Mammalodon colliveri. Length of skull about 45 cm. (Credit: Image: Rodney Start / Source: Museum Victoria)"

Source: Wiley-Blackwell