Dr. Gabriel Aguirre and Professor Ewan Fordyce from Department of Geology at the University of Otago in New Zealand have discovered fossils of an ancient dolphin species, named Papahu taitapu. It was discovered in the marine sedimentary rocks in the Cape Farewell region of northern South Island. Papahu is claimed to be closely related to the ancestors of modern dolphins and toothed whales.

The fossils, comprising of a skull, a jaw and few other parts, dates back to the Early Miocene times, between 19 and 22 million years. Researchers only found one single specimen. The fossil has been placed in the University's Geology Museum.

This is a significant discovery because it is one of few dolphin fossils discovered from that period. Fordyce said that the findings could explain how ancient dolphins evolved.

Papahu taitapu was six feet long (like common dolphins) and had conical teeth just like modern dolphins. They had a wider head and lived in the shallow seas around proto-New Zealand (Zealandia) along with ancient penguins and baleen whales. The temperatures in the region were warm at the time.

"Our study of structures of the skull and earbone suggest that Papahu could make and use high-frequency sound to navigate and detect prey in murky water," Aguirre said in a statement. "They probably also used sound to communicate with each other."

Papahu is considered to be a member of the now extinct species of shark-toothed dolphins that evolved and spread globally 19-35 million years ago. They have been replaced by modern dolphins and toothed whales that developed within the last 19 million years.

"When we look at it we think, gosh, it's a dolphin, ok, and it's a bit like modern forms, but when we look closely, it differs in quite a few fine details," Fordyce told Radio New Zealand. "The structures in this little Papahu dolphin help us understand the transition from the very early archaic extinct dolphins into some of the more modern forms.

The finding has been published in the Journal of Vertebrate Paleontology.