A fossilized skull dug up in Virginia more than four decades ago has been identified as a remarkably close relative of the narwhal and beluga whales that swim in Canada's northern waters today.
Bohaskaia monodontoides apparently lived in southerly oceans three to four million years ago, according to Postmedia News.
The skull was unearthed in a Virginia gravel pit in 1969 but sat in the Smithsonian National Museum Collection until researchers used modern techniques to analyze it.
They concluded it came from an extinct whale that had strong similarities to the white-skinned beluga, as well as the narwhal, best known for the single long tusk protruding from its head.
"Fossils referred to as belugas have been known from fragmentary bits, but skulls are so revealing because they contain so many informative features," Nicholas Pyenson, a paleobiologist with the Washington, D.C.-based Smithsonian Institution, said in a summary of the study. "We realized this skull was not something assignable to a beluga, and when we sat down, comparing the fossil side by side with the actual skulls of belugas and narwhals, we found it was a very different animal."
Pyenson and research partner, Smithsonian post-doctoral fellow Jorge Velez-Juarbe, published their findings in the latest issue of the Journal of Vertebrate Paleontology.
Their research, and the discovery of another extinct, beluga-related whale in northwestern Mexico, led them to conclude that small, toothed whales originated in southerly oceans before their descendants adapted to life in harsher Arctic and sub-Arctic waters.
Velez-Juarbe, who initiated the second look at the skull fossil in 2010, said the northward evolution of the narwhal and beluga may have been due to changes in the ocean food chain.
"The fact is that living belugas and narwhals are found only in the Arctic and sub-Arctic, yet the early fossil record of the monodontids extends well into temperate and tropical regions," Pyenson said, according to MSNBC. "For evidence of how and when the Arctic adaptations of belugas and narwhals arose we will have to look more recently in time."