Paleontologists have described a new baleen whale species that swam around the North Sea some 3 million years ago. Antwerpibalaena liberatlas is an extinct cousin of the modern right whales. The well-preserved fossil skeleton was found in 2013 during the construction of the Kieldrecht Lock in the port of Antwerp. An extensive study of the anatomical differences now provides more insight into the evolution of the balaenid whales, which, due to a lack of well-described fossils, remained unclear until now.
In February 2013, paleontologist Stijn Goolaerts of the Royal Belgian Institute of Natural Sciences (RBINS) discovered a well-preserved fossil whale skeleton in the construction site of the Kieldrecht Lock in the Port of Antwerp. After an investigation by an international team led by Guillaume Duboys de Lavigerie (RBINS, University of Liège) and Felix Marx (Te Papa Museum, New Zealand) it turns out to be a completely new species of right whale that swam the waters near nowadays Antwerp some 3 million years ago.
Stiff neck and paddle-shaped flippers
Right whales and the bowhead whale belong to the family Balaenidae, a group of whales that evolved about 20 million years ago. They are the oldest group of baleen whales known today. But due to a lack of well-documented fossil finds, little is known about their evolution. The skeleton of Antwerpibalaena liberatlas now provides new information. Their 'stiff neck', for example. In today's right whales - the North Atlantic right whale, the North Pacific right whale and the Southern right whale - and the bowhead whale, the neck vertebrae are completely fused. This provides better support for the head, which takes up a third of the body length of the skim-feeders. Antwerpibalaena already had a sturdy neck, but not as pronounced as in right whales today: its atlas vertebra was still loose, hence its species name liberatlas.
The palaeontologists also note that Antwerpibalaena already had paddle-shaped flippers, another typical feature of the extant right whales.
Evolutionary yo-yo
Antwerpibalaena was between 9.5 and 12 meters long. The new find is significantly smaller than the recent representatives of the family (15 to 20 meters), but also smaller than some older right whales. So the evolution of the body size in these whales was not a straight line, from small to large, but a more complex story. “For now, it remains unclear why some right whale lineages were smaller. Perhaps because they lived in other marine regions, in shallower and more enclosed waters, or in relation to different feeding strategies”, says palaeontologist Olivier Lambert (RBINS), co-author of the study.
The new whale's name is dedicated the city of Antwerp, because the Antwerp subsoil is known as a true cetacean cemetery. After more than 150 years of excavation and research, scientists are still making important discoveries there.
The study is published in the journal Journal of Systematic Palaeontology.
The scientists would like to thank all those who made the excavations in the Kieldrechtsluis possible, especially the chief engineers and the volunteers. Without those helping hands, this special piece of heritage would have been irreversibly lost. Indeed, the Flemish palaeontological heritage is not protected by the state like archaeological heritage.
