Paleontologists have unveiled a remarkable new species of extinct whale from New Zealand with both baleen and tooth sockets–part of a growing story of how modern baleen whales, like blues and humpbacks, evolved from toothed ancestors.
The new whale has been dubbed Waharoa ruwhenua. The genus name means “long mouth” in the Māori language, using the words waha, “mouth,” and roa, “long.” The species name also is from Māori, using the words ru, “shaking,” and whenua, “land,” in reference to “The Earthquakes,” the name of the spot where the first skeleton was discovered.
Waharoa is known from the partial skeletons of three individuals, an adult and two juveniles. The fossils are described by Drs. Robert W. Boessenecker and R. Ewan Fordyce of the University of Otago in Dunedin. The scientific paper was published online on September 10 in the open-access journal PeerJ and is freely available here.
The fossils of Waharoa were collected from a geological layer called the Otekaike Limestone and date to between 27.3 and 25.2 million years ago. This age places the new whale in an interval of geological time called the Oligocene Epoch.
The authors analyzed the evolutionary relationships of Waharoa and found that it belongs to an entirely extinct group of early baleen whales called Eomysticetidae.
“The skulls of these three specimens were spectacularly preserved, revealing that eomysticetids had unusually long and delicate surfboard-like snouts, with blowholes placed far forward on the skull, and enormous attachment areas for jaw muscles,” Boessenecker said in a statement.
Waharoa and its relatives belong to a much larger group called Mysticeti, or mysticetes, which includes all the baleen whales. Although its adult size of five to six meters makes Waharoa a bit small compared to modern mysticetes, its fossils reveal a combination of anatomical features transitional between the most primitive mysticetes, which still had mouths full of teeth, and the modern mysticetes, which have baleen instead of teeth.
Waharoa had baleen in the back of its mouth, but at the front of its jaws were small vestigial tooth sockets. Also, its nostril openings were situated farther forward on the top of its head than in living mysticetes. Waharoa probably fed by skimming through the water, engulfing plankton.
Waharoa is the third new eomysticetid from the Oligocene of New Zealand named by Boessenecker and Fordyce in 2015. The other two are Tohoraata and Tokarahia.