The newly-identified species, named the Ramari’s beaked whale (Mesoplodon eueu), occurs throughout temperate southern hemisphere waters, with reports from several locations off South Africa, Australia, and Aotearoa New Zealand.
“The Earth’s deep ocean remains less understood than the surface of Mars,” said University of Auckland’s Dr. Emma Carroll and colleagues.
“However, much biodiversity is waiting to be discovered in the deep sea, and there is great potential for this region to contribute to and challenge major ecological hypotheses.”
“Beaked whales (ziphiids) are among the most visible inhabitants of the deep sea, due to their large size and worldwide distribution, and their taxonomic diversity and much about their natural history remain poorly understood.”
“We combine genomic and morphometric analyses to reveal a new southern hemisphere ziphiid species, the Ramari’s beaked whale (Mesoplodon eueu), whose name is linked to the Indigenous peoples of the lands from which the species holotype and paratypes were recovered.”
In their research, the authors aimed to investigate the taxonomic status of disjunct populations of the True’s beaked whale (Mesoplodon mirus).
They collected and analyzed genomic and morphological data from several museum and archival specimens from northern and southern hemispheres.
One of the specimens, which turned out to belong to the new species, was found on November 27, 2011 in New Zealand.
“Almost a decade ago, a female whale washed ashore on the west coast of Te Waipounamu (South Island), Aotearoa New Zealand. She was 5 m long and pregnant,” the researchers said.
“The local tribe of Ngāti Māhaki named her Nihongore and her bones were sent to Te Papa Tongarewa Museum in Wellington-New Zealand for preservation.”
“Initially, we thought this was the first True’s beaked whale found in the country, but that changed during our work with a global network of researchers,” they added.
“We soon realized that the genetics and skull shape of True’s beaked whales in the northern hemisphere were very different to True’s beaked whales in the southern hemisphere.”
“They have been separated for around half a million years, probably because they don’t like the warm water near the equator. It’s clear that they are different species.”
This global map shows the connectedness of the ocean, with sampling locations in the North Atlantic (black circles) and southern hemisphere (yellow circle) and distribution of the True’s beaked whale (Mesoplodon mirus) and the Ramari’s beaked whale (Mesoplodon eueu), with the artist’s impression of the new species in top right. Image credit: Vivian Ward, University of Auckland.
The discovery of the Ramari’s beaked whale brings the total number of beaked whale species to 24.
“These are the most visible inhabitants of the deep ocean due to their large size and need to surface to breath,” the scientists said.
“The group includes the deepest diving mammals, which can dive 100s or 1,000s of meters to find their prey.”
“The Ramari’s beaked whale probably spends a lot of time offshore in deep waters given so few specimens have been discovered.”
The team’s paper was published in the Proceedings of the Royal Society B: Biological Sciences.
Emma L. Carroll et al. 2021. Speciation in the deep: genomics and morphology reveal a new species of beaked whale Mesoplodon eueu. Proc. R. Soc. B 288 (1961): 20211213; doi: 10.1098/rspb.2021.1213