The newly-identified species of extinct diving duck is the fourth species in the genus Manuherikia.
Manuherikia primadividua lived between 16 and 19 million years ago on a huge paleolake called Lake Manuherikia.
The bird’s fossilized remains were recovered from the Early Miocene Bannockburn Formation exposed near St Bathans, Central Otago, New Zealand.
“The duck appears to have replaced another, related duck species, Manuherikia lacustrina, at some point in the 3-million-year period preserved in the fossil record at St Bathans,” said Dr. Trevor Worthy, a paleontologist at Flinders University.
“We haven’t found these two ducks in the same fossil layer, and we think that’s because they lived at different times, with Manuherikia primadividua outcompeting and eventually replacing its older cousin.”
“The switch in duck species may well occur at the same time as a change in the vegetation in the region, revealed by pollen studies years ago. If so, this may be evidence of climate change affecting the St Bathans Fauna.”
Manuherikia primadividua is one of four species in the genus Manuherikia that paleontologists have found at St Bathans, and one of nine waterfowl species.
“Manuherikia primadividua and Manuherikia lacustrina will allow many of the other finds from St Bathans to be dated,” said Dr. Paul Scofield, senior curator of natural history at Canterbury Museum.
“If we find a new species alongside Manuherikia lacustrina fossils, we know it lived in this earlier period, whereas if it’s alongside the new species it lived a bit later.”
“So it allows us to start putting all the animals we’ve found at St Bathans in some sort of chronological order for the first time.”
The discovery of Manuherikia primadividua underpins the importance of knowing exactly which layer a fossil derives from.
“It is an important step in building up a picture of how the animals and plants living on this ancient lake changed over time,” Dr. Scofield said.
The team’s paper was published in the journal Geobios.
Trevor H. Worthy et al. A new species of Manuherikia (Aves: Anatidae) provides evidence of faunal turnover in the St Bathans fauna, New Zealand. Geobios 70: 87-107; doi: 10.1016/j.geobios.2021.08.002
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