A genome study published in Communications Biology in April 2026 and announced by the University of California, Berkeley on May 8 gave the world a penguin species it did not have before: Pygoscelis kerguelensis, the southeastern gentoo penguin, which breeds on the Kerguelen Islands in the southern Indian Ocean. Berkeley calls it the first new penguin species named in more than 100 years.
Kerguelen, known in French as the Desolation Islands, lies nearly 2,000 miles from any permanently inhabited landmass, and the birds there had been counted as ordinary gentoos all along. Nothing about the discovery is recent, though. Coverage resurfaced in late September, and the finding is five months old, so the useful question is what the split established and what it left open.
Sixty-four genomes from ten colonies
The team, with Daly Noll of the University of Chile as first author and Juliana Vianna, Rauri Bowie and Elie Poulin as senior authors, sequenced the whole genomes of 64 gentoo penguins from 10 breeding colonies, according to the ScienceDaily copy of the Berkeley release. The paper itself reports about 9.16 million genetic variants at roughly 11.7-fold genome coverage and pairs the sequences with physical measurements, habitat modeling and searches for genes under selection.
Gentoos turned out to be four lineages, not one, and the boundaries between them line up with real ocean barriers. The paper finds signals of positive selection in genes tied to thermoregulation, oxygen transport, metabolism and skeletal development, patterns consistent with adaptation on either side of the Antarctic Polar Front.
Four species and where each one breeds
According to Berkeley’s May 8 announcement, the study is the first to span nearly the whole range of the gentoo. It recognizes Pygoscelis kerguelensis, the southeastern gentoo, on Kerguelen and probably Heard Island; Pygoscelis taeniata, the eastern gentoo, on the Crozet, Marion and Macquarie Islands; Pygoscelis papua, the northern gentoo, on the Falkland/Malvinas and Martillo Islands; and Pygoscelis ellsworthi, the southern gentoo, on the Antarctic Peninsula, coastal Antarctica and South Georgia. Only the Kerguelen animals are newly recognized. The other three names existed already, as forms once treated as subspecies.
Speciation was slow and driven by geography. BirdGuides quotes the paper as saying that isolation on remote island groups, combined with limited dispersal and local adaptation, drove speciation over the past 300,000 to 500,000 years.
A taxonomy fight older than the genomes
Rauri Bowie, a Berkeley professor, said in the announcement, “There’s probably no species of penguin where the taxonomy has been more debated than the gentoo penguin.” He added, “For over 100 years it’s been controversial as to how many species or how many subspecies there are.” The doubt ran in both directions, and earlier work had already pushed toward a split.
In November 2020 the University of Bath’s Jane Younger and colleagues, writing in Ecology and Evolution, argued that gentoos are four species after comparing genome data and museum specimens from the Falkland Islands, South Georgia, the South Shetland Islands and Kerguelen, finding differences in bone length and in beak size and shape. Bath’s Milner Centre for Evolution, where Younger is a prize fellow, framed the result as the first demonstration that the penguins are physically as well as genetically distinct. The new study widens the sampling to ten colonies and adds selection and climate analyses, which is what turned a proposal into a formal species description.
Island species with a 2050 habitat forecast
The naming carries a warning, and a practical consequence: a species thought to be one abundant bird becomes four populations, each with its own smaller numbers, its own home islands and its own exposure to a warming ocean. Three of the four species live on sub-Antarctic islands, and under moderate warming scenarios the study projects they could lose suitable habitat on those islands by 2050, with few alternative places to go. Only the southern gentoo is predicted to expand its range as Antarctic conditions shift.
The Kerguelen birds are notable for another reason. WISN’s report and the paper both describe unusually high genetic diversity in that lineage, a pattern the authors read as evidence that the archipelago acted as a refuge during past ice ages, the kind of place where lineages that had drifted apart met again. Elevated diversity of that sort is a reason to protect the population as a store of genetic variation, separate from the question of how many birds live there, a count the sources reviewed do not give.
Vianna, the co-senior author, said conservation institutions in all the countries involved need to recognize the split and act on it. The sources reviewed for this article do not say whether the IOC, Clements or the IUCN Red List has formally adopted the four species, so whether the newest penguin gets its own conservation assessment is unresolved.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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