December 20th, 2012 by Michael Ricciardi
In 2002, the body of a strange looking whale resembling both a right whale and a bowhead was found washed ashore near Golden Bay, New Zealand.
Now, a new analysis of the creature’s DNA and skull concludes that it is/was in fact a pygmy right whale (Caperea marginata), a rarely seen baleen whale that lives only in the deep, open ocean, and is related to an ancient family of baleen (mysticeti) whales believed to have gone extinct at least 2 million years ago.
But apparently, enough of the ancient whale clade, known as cetotheres, survived, in some form, to pass on their genes through related variants over those past millions of years. But the phylogenetic history of the whales is largely unknown.
This pygmy right whale could be one of the very last of its kind.
“The living pygmy right whale is, if you like, a remnant, almost like a living fossil. It’s the last survivor of quite an ancient lineage that until now no one thought was around.” stated Felix Marx, a paleontologist at the University of Otago in New Zealand
Considered the most elusive of the baleen whales, pygmy right whales typically grow to about 21 feet (6.5 meters) long (hence the name “pygmy whale”) and are thought to inhabit only waters of the Southern Hemisphere. They have been sighted at sea only a few dozen times, making studying them difficult; their behavioral patterns and social structures are complete mysteries.
The whale’s snout suggested that it was a relative of the bowhead whale, but there are no fossil studies of pygmy whale evolution to prove this.
To determine where the pygmy right whales fit into the cetacean tree of life, Marx and his team conducted an analysis and comparison of the recent specimen with the fossilized skulls and bones from other ancient whales. It was then that the team noted the strongest resemblance to the cetotheres.
Although they are related to other baleen whales, like humpbacks and blue whales, the pygmy right whales are rather different-looking from others of their kind, with their pronounced, arched mouth and snout. A gene sequence analysis indicated that these pygmy whales diverged from other baleen whales between 17 and 25 million ya, which explains their different morphology.
The extinct family Cetotheriidae emerged at some point after this — estimated to be about 15 million ya — and thrived for many millions of years afterwards, occupying all the world’s oceans.
This recent analysis involved comparison of 166 morphological characters and 23 taxa,”representing all the living and extinct families of toothless baleen whales.” Results supported the hypothesis that the pygmy whale is indeed a descendent of the Cetotheriidae and help to “clarify the origins of a long-problematic living species.”
Researchers hope that the new information will aid the reconstruction of this ancient lineage of “lost” cetacea and perhaps reveal details of how they lived.
Top photo: The pygmy whale, a mysterious cetacean that looks radically different from all living whales, is actually the last living member of a group thought to have gone extinct 2 million years ago. Photo credit: Darryl Wilson, University of Otago
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