Daniel Field
My research investigates the evolutionary history and fossil record of vertebrate animals, with a primary focus on birds (although I have worked on many groups including whales, sharks, snakes, turtles, and horned dinosaurs).
For more information, links to publications, and to see photographs from recent fieldwork, please see my webpage: http://danieljfield.com
For more information, links to publications, and to see photographs from recent fieldwork, please see my webpage: http://danieljfield.com
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exceedingly sparse avian fossil record from the Mesozoic era. The most ancient
phylogenetic divergences among crown birds are known to have occurred in the
Cretaceous period1–3, but stem-lineage representatives of the deepest subclades of
crown birds—Palaeognathae (ostriches and kin), Galloanserae (landfowl and
waterfowl) and Neoaves (all other extant birds)—are unknown from the Mesozoic era.
As a result, key questions related to the ecology4,5, biogeography3,6,7 and divergence
times1,8–10 of ancestral crown birds remain unanswered. Here we report a new
Mesozoic fossil that occupies a position close to the last common ancestor of
Galloanserae and fills a key phylogenetic gap in the early evolutionary history of
crown birds10,11. Asteriornis maastrichtensis, gen. et sp. nov., from the Maastrichtian
age of Belgium (66.8–66.7 million years ago), is represented by a nearly complete,
three-dimensionally preserved skull and associated postcranial elements. The fossil
represents one of the only well-supported crown birds from the Mesozoic era12, and is
the first Mesozoic crown bird with well-represented cranial remains. Asteriornis
maastrichtensis exhibits a previously undocumented combination of galliform
(landfowl)-like and anseriform (waterfowl)-like features, and its presence alongside a
previously reported Ichthyornis-like taxon from the same locality13 provides direct
evidence of the co-occurrence of crown birds and avialan stem birds. Its occurrence in
the Northern Hemisphere challenges biogeographical hypotheses of a Gondwanan
origin of crown birds3, and its relatively small size and possible littoral ecology may
corroborate proposed ecological filters4,5,9 that influenced the persistence of crown
birds through the end-Cretaceous mass extinction.
exceedingly sparse avian fossil record from the Mesozoic era. The most ancient
phylogenetic divergences among crown birds are known to have occurred in the
Cretaceous period1–3, but stem-lineage representatives of the deepest subclades of
crown birds—Palaeognathae (ostriches and kin), Galloanserae (landfowl and
waterfowl) and Neoaves (all other extant birds)—are unknown from the Mesozoic era.
As a result, key questions related to the ecology4,5, biogeography3,6,7 and divergence
times1,8–10 of ancestral crown birds remain unanswered. Here we report a new
Mesozoic fossil that occupies a position close to the last common ancestor of
Galloanserae and fills a key phylogenetic gap in the early evolutionary history of
crown birds10,11. Asteriornis maastrichtensis, gen. et sp. nov., from the Maastrichtian
age of Belgium (66.8–66.7 million years ago), is represented by a nearly complete,
three-dimensionally preserved skull and associated postcranial elements. The fossil
represents one of the only well-supported crown birds from the Mesozoic era12, and is
the first Mesozoic crown bird with well-represented cranial remains. Asteriornis
maastrichtensis exhibits a previously undocumented combination of galliform
(landfowl)-like and anseriform (waterfowl)-like features, and its presence alongside a
previously reported Ichthyornis-like taxon from the same locality13 provides direct
evidence of the co-occurrence of crown birds and avialan stem birds. Its occurrence in
the Northern Hemisphere challenges biogeographical hypotheses of a Gondwanan
origin of crown birds3, and its relatively small size and possible littoral ecology may
corroborate proposed ecological filters4,5,9 that influenced the persistence of crown
birds through the end-Cretaceous mass extinction.