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Vegavis gen. nov. - new anseriform in today's Nature



In today's Nature:

Clarke, J. A., C. P. Tambussi et al. 2005. Definitive fossil evidence for
the extant avian radiation in the Cretaceous. Nature 433: 305-308.

"Long-standing controversy surrounds the question of whether living bird
lineages emerged after non-avian dinosaur extinction at the
Cretaceous/Tertiary (K/T) boundary or whether these lineages coexisted with
other dinosaurs and passed through this mass extinction event. Inferences
from biogeography and molecular sequence data project major avian lineages
deep into the Cretaceous period, implying their 'mass survival' at the K/T
boundary. By contrast, it has been argued that the fossil record refutes
this hypothesis, placing a 'big bang' of avian radiation only after the end
of the Cretaceous. However, other fossil data?fragmentary bones referred to
extant bird lineages have been considered inconclusive. These data have
never been subjected to phylogenetic analysis. Here we identify a rare,
partial skeleton from the Maastrichtian of Antarctica as the first
Cretaceous fossil definitively placed within the extant bird radiation.
Several phylogenetic analyses supported by independent histological data
indicate that a new species, Vegavis iaai, is a part of Anseriformes
(waterfowl) and is most closely related to Anatidae, which includes true
ducks. A minimum of five divergences within Aves before the K/T boundary are
inferred from the placement of Vegavis; at least duck, chicken and ratite
bird relatives were coextant with non-avian dinosaurs."

The phylogenetic analysis used the Clarke and Norell (2002) dataset to
identify _Vegavis_ as neornithean, then the Mayr & Clarke (2003) dataset to
establish a place among Anseriformes (in an unresolved trichotomy with
_Presbyornis_ and Anatidae - _Vegavis_ was originally identified as
'Presbyornithidae indet.', but the authors here find nothing to link it
specifically to _Presbyornis_).

    Cheers,

        Christopher Taylor