A recent research from the Argentinean Museum of Natural Sciences Bernardino Rivadavia in Buenos Aires, Argentina, proposes that birds similar to geese and sharing traits with these and ducks and chickens survived the extinction process that ended the dinosaurs at the end of the Cretaceous , 66 million years ago. The Science of Nature publishes the results.
Las Vegaviidae, a newly named group of waterfowl, are now extinct, are the first that science recognizes as survivors of mass extinction, says Federico Agnolin, a member of the museum team. As early as 2005, the aquatic species Vegavis iaai, discovered on Vega Island in Western Antarctica, had been recognized by science as such, but recent Argentine works reveal that it was not alone in its feat.
Antecedent
Last year, paleontologists described a second Vegavis fossil that included a syrinx, the bird’s version of the vocal cords, and concluded that these birds squawked like geese. A comparative analysis with other fossils of birds in the southern polar regions revealed that the Vegavis species formed a group with three other species and some unnamed fossils, mostly fragmentary, which has now been christened Vegaviidae.
Two of the Vegaviidae lived during the Upper Cretaceous: the Polarornis gregorii in Antarctica and the Neogaeornis wetzeli in Chile. The third species, Australornis lovei, appeared rather shortly after the extinction of the great saurians in New Zealand, suggesting that it survived the mass extinction.
CONCLUSIONS
Los indicios en los huesos de las Vegavis y Polarornis señalan que estos crecieron rápidamente, algo que también ocurre en las aves modernas, lo cual habría sido un factor crítico en su supervivencia, en comparación con otras especies aviares que perecieron al final del Cretácico como los Enantiornithes o pájaros opuestos.
“In addition, vegaviids represent the first avian lineage that definitely crossed the K-Pg [transition from the Cretaceous to the Paleogene], which supports the idea that some avian clades were not affected by the final Mesozoic mass extinction event, counteracting previous interpretations. The recognition of Vegaviidae indicates that modern birds diversified in the southern continents during the Cretaceous and reinforces the hypothesis that indicates the important role of Gondwana for the evolutionary history of Anseriformes and Neornithes as a whole “concludes this work.
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