Scientists have reconstructed the skeleton of a prehistoric penguin species, and found that its body was unlike any previously known penguin.

“It’s almost like someone took an emperor penguin and stretched it out,” says Daniel Ksepka, an avian paleontologist at North Carolina State University who helped to reassemble the fossils. The new species (from the genus Kairuku) is sleeker and more slender than other penguins. It has lengthy flippers for its size and a long and narrow beak. And at four feet two inches tall, the svelte Kairuku was nearly 12 inches taller than the tallest living penguin today, the emperor penguin.

The first nearly complete Kairuku skeleton was discovered in 1977, but more recent discoveries helped to fill in some of the missing pieces of the body plan. The first complete reconstruction of the 25-million-year-old penguin is slated for publication on March 1 in the Journal of Vertebrate Paleontology.

Kairuku and at least five other types of prehistoric penguins lived together in New Zealand, which in modern times has the highest diversity of living penguins. But Kairuku went extinct without leaving any descendents. “They’re not related to living species, but they were an interesting side chapter,” says Ksepka. “It’s cool to see a new type of penguin, and it highlights the fact that this was really a diverse ecosystem of penguins.”