Vegavis Iaai

''Vegavis'' is a genus of extinct bird that lived in Antarctica during the Maastrichtian stage of the Late Cretaceous. The type and only species is ''Vegavis iaai'', representing one of the earliest known crown group birds. Initially described as member of Anseriformes within Galloanserae, the definitive taxonomic position of ''Vegavis'' was debated among paleontologists over two decades until the 2025 description of a nearly complete skull, discovered in 2011, supported its original classification.

Taxonomy

The genus name, ''Vegavis'', is a combination of the name of Vega Island and "avis", the Latin word for bird, while the species name, "iaai", is after the acronym for Instituto Antartico Argentino (IAA), the Argentine scientific expedition to Antarctica. The holotype is held by the Museo de La Plata, Argentina. The specimen, cataloged as MLP 93-I-3-1, was found in 1993 from the López de Bertodano Formation at Cape Lamb on Vega Island, Antarctica, and was first thought to be an indeterminate presbyornithid. It was only described as a new species in 2005, because it consists of the very delicate remains of one bird embedded in a concretion, which had to be meticulously prepared for study. CT scans were utilized to gain a clearer picture of the bone structure without running danger of damaging or destroying the fossil.Supporting information
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A second specimen, MACN-PV 19.748 (formerly MLP 93-I-3-2), was found beside the holotype specimen. It was preserved in three dimensions, so CT scans were again utilized to visualize the intact syrinx of this specimen. The syrinx has an asymmetrical third segment, suggesting that ''Vegavis'' had two sources of sound in the neck and along with large soft-tissue resonating structures. This indicates that it was likely capable of honks as in ducks, geese, and other basal neognaths. Other potential specimens have also been reported, including a distal tarsometatarsus (AMNH FARB 30913) tentatively identified as cf. ''Vegavis'', an isolated femur (SDSM 78247) referred to as ''Vegavis'' sp., and a synsacrum (MN 7832-V) referred to as cf. ''V. iaai''.

After 20 years since the formal naming of ''Vegavis'', a nearly complete skull specimen (AMNH FARB 30899) discovered by Eric M. Roberts in 2011 from the López de Bertodano Formation was officially described in 2025. The morphology of this skull supports the placement of ''Vegavis'' within crown-group Aves, specifically as a member of the Anseriformes, and provides novel insight into its feeding ecology.

Classification

''Vegavis'' was initially described as a member of the crown group Anseriformes within Galloanserae, indicating that some representatives of the modern bird groups lived in the Mesozoic.

However, some paleontologists questioned its affinities to Anseriformes or Galloanserae, with some classifying it as a stem-group bird within Ornithurae, a crown group bird outside Galloanserae, a sister taxon of the Neornithes or at the base of Neognathae with an unresolved position. In contrast, ''Vegavis'' was recovered as a sister taxon of Anatidae or Anseriformes within Galloanserae based on other phylogenetic analyses. In a 2025 study which described a nearly complete skull of ''Vegavis'', Torres et al. supported its placement within crown group Anseriformes, sister to '' Conflicto'' and ''Anas'', based on their revised phylogenetic analyses.

Agnolín et al. (2017) proposed the family Vegaviidae as stem-group Anseriformes containing ''Vegavis'', ''Polarornis'' and several other extinct avian genera, but the monophyly of this clade was questioned by subsequent studies. The fragmentary ''Polarornis'' might possibly belong to this clade, but the reported specimens are poorly preserved to resolve its taxonomic affinities. Worthy et al. (2017) also proposed the order "Vegaviiformes" to include Vegaviidae, but this is a disused clade that has never been mentioned by other researchers except for the describers of '' Conflicto antarcticus''.

Paleobiology

''Vegavis'' was a bird with a high metabolism, which allowed it to live at high latitudes in Antarctica. It also shows a degree of osteosclerosis, a condition shared with ''Polarornis''. This different degrees of osteosclerosis could be related to variations in diving behaviour.

See also

* ''Asteriornis''

References

External links

'Dinosaurs Mingled with Cousins of Ducks and Chickens', from Live Science

‘These Are the Dinosaurs That Didn't Die’, from National Geographic

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Prehistoric bird genera
Cretaceous birds of Antarctica
Fossils of Antarctica
Fossil taxa described in 2005