New storm-petrel species emerges from Wilson's shadow
A taxonomic reappraisal of Wilson’s Storm-Petrel reveals a cryptic highland species in Chile - now named the Andean Storm-Petrel.
A new name takes flight
The stormy lineage of the seabird genus Oceanites has gained a new and remarkable member: Oceanites barrosi, the Andean Storm-Petrel. Officially described in a 2024 study published in *Zootaxa*, this high-elevation seabird is not only distinct in plumage, structure, and genetics - it’s also the first member of the genus definitively tied to inland breeding in the central Andes of Chile.
Originally misclassified as part of the widespread Wilson’s Storm Petrel Oceanites oceanicus chilensis, this taxon had remained hidden in plain sight. A mix of genetic data, morphological measurements, and biogeographic analysis now supports its status as a full species. Named in honour of Chilean ornithologist Rafael Barros Valenzuela, who first collected specimens in 1924, O. barrosi was confirmed by recent fieldwork and DNA sequencing.
Highland seabird with a coastal cousin
Unusually for a storm-petrel, O. barrosi appears to breed in alpine environments well above treeline. The holotype, collected at 1,402 metres in the Valparaíso region, suggests a breeding range far removed from the coastal and pelagic habitats typical of its relatives. The species is genetically closest to the enigmatic Oceanites pincoyae, the Pincoya Storm-Petrel, though the two are separated by considerable geographic distance and over six million years of evolutionary divergence.
In flight, the Andean Storm-Petrel is identifiable by its protruding yellow-webbed feet, distinctive white rump patch, and a bold double pale line on the underwing. Morphologically, it sits midway between the smaller O. pincoyae and the slightly larger O. chilensis, and it lacks the extensive white belly typical of several other species in the genus.
A reshaped genus and deeper questions
The discovery of O. barrosi comes alongside a major revision of the genus Oceanites. Using mitochondrial DNA (cytochrome b) and detailed morphometric data, the study recognises seven distinct species, up from three. This includes the elevation of O. chilensis and O. exasperatus from subspecies to species rank, and the recognition of strong genetic structure within what was once a broadly defined O. oceanicus complex.
The phylogenetic analysis confirms that Oceanites is monophyletic and dates its initial divergence from other storm-petrels to roughly 32 million years ago. The basal position of O. chilensis suggests that the genus originated in the Southern Ocean, with subsequent colonisations of the Pacific and Atlantic occurring through rare jump-dispersal events.
Conservation urgency in the mountains
With no nest sites yet discovered and little known about its population size or breeding behaviour, O. barrosi joins the growing list of recently described storm-petrels whose conservation status remains uncertain. Recent evidence, including sightings of fledglings and adults near Santiago, suggests a highly restricted and potentially vulnerable breeding range in the central Andes. Two rescued individuals even laid eggs in captivity before dying, providing indirect but compelling evidence of breeding in the highland interior.
“The urgency now,” the authors note, “is to locate nesting colonies and assess the species’ conservation needs.” Three of the seven recognised Oceanites species - including barrosi, pincoyae, and galapagoensis - still have no confirmed nest records. Given the growing pressure on mountain habitats, filling these gaps is critical.
A tribute to overlooked heritage
By naming the species after Rafael Barros Valenzuela, the study honours a long-neglected figure in South American ornithology. His century-old specimen, once misidentified and later forgotten, has now become the holotype of a distinct species - an extraordinary resolution to a puzzle that took nearly a hundred years to solve.
In unveiling Oceanites barrosi, the authors have not only expanded the known diversity of storm-petrels but also highlighted how much remains unknown about even the world’s most elusive seabirds. As new species emerge from the mist of overlooked data and rediscovered specimens, the Andes once again prove themselves a cradle of hidden avian life.
01 May 2025
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