A whale fossil unearthed three decades ago in New Zealand’s South Canterbury district has led to an unexpected find that rewrites the history of whale evolution, National Geographic reports.\nThe fossil dates back 27 million years ago and was identified as a previously unknown genus of baleen whale.\nAlthough discovered for quite some time, the fossil — a skull and an assortment of associated bones — has only now been studied by two researchers at the University of Otago.\nThe long-overdue analysis — conducted by Professor Ewan Fordyce of the university’s geology department and former Ph.D. student Cheng-Hsiu Tsai — revealed that the ancient remains actually belonged to the oldest ancestor of living baleen whales, the university announced in a news release.\n“This is a pretty old whale that goes almost half-way back to the age of the dinosaurs,” Fordyce explained.\n“It’s about as old a common ancestor as we have for the living baleen whales like the minke whales and the right whales,” he added.\nThe pair have named the newfound genus Toipahautea waitaki (Maori for “baleen-origin whale from the Waitaki region”) and have published a study in the journal Royal Society Open Science describing their discovery.\nBaleen whales, part of the Mysticeti cetacean suborder, are named after the baleen plates in their upper jaw, which replace teeth. These whales feed by swallowing large quantities of seawater and then using the baleens to filter the krill that get sucked in along with it.\n\n“As sure as the sun rises in the east, we are going to find older baleen whale specimens,” says Fordyce. “But right now, it anchors the modern baleen whale lineage to at least 27.5 million years.” https://t.co/Ls9KVpfmvI @otago @DPHocking @NatGeo #FossilFriday\n— John Pickrell ???? (@john_pickrell) April 20, 2018\n\nToday’s baleen whales are among the planet’s largest cetaceans and include a broad range of whale species, notes National Geographic.\nThe baleen group comprises everything from the 112-feet-long blue whale to the 35-feet-long minke whale. On this list of cetacean giants are featured some of the most famous names of the whale world, such as the fin whale (the second largest, after the blue whale), the humpback, the right, and the bowhead whale.\nBut it seems these modern-day baleen whales are considerably bigger than their newfound ancestor.\nAccording to Fordyce, the Toipahautea waitaki fossil was roughly “half the size of an adult minke whale.” Considering that minkes are the second smallest baleen whales (after the pygmy right whale), the fossil’s size was indeed quite modest.\nStuff.co.nz reports that the newfound fossil belonged either to a juvenile or to a physically immature young adult.\nThe skeleton unearthed in South Canterbury’s rural Hakataramea Valley measured only about 16.4 feet in body, while the skull added another 3.2 feet to the total length of the fossil.\n\nAmazing- 'Oldest' baleen whale in the world found in a South Island quarry https://t.co/atoI0Fetkg pic.twitter.com/acnXtE4wh6\n— Nature Kicks (@naturekicks) April 20, 2018\n\nThis archaic baleen whale had long and narrow toothless jaws, which suggests it fed in a similar way to the minke whales we see today, notes the news release.\nThis is an important discovery in itself, because it debunks the previously circulated theory that baleen whales initially started out with teeth and then grew the baleens between individual teeth, states Yahoo! News.\nThe two researchers that identified Toipahautea waitaki believe that even older fossils of baleen whales will be discovered in the future.\n“As sure as the sun rises in the east, we are going to find older baleen whale specimens,” said Fordyce.\n“But right now, it anchors the modern baleen whale lineage to at least 27.5 million years,” he concluded.