The morphology and systematics of Mammalodon colliveri (Cetacea: Mysticeti), a toothed mysticete from the Oligocene of Australia. 2009. E. Fitzgerald. Zool. J. Linn. Soc., published online 21 Dec.
New work 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. Mammalodon colliveri, a primitive toothed baleen whale from the Oligocene, may have used its tongue and short, blunt snout to suck small prey from sand and mud on the seafloor
Mammalodon had a total body length of about 3 m, 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. link