''Patagopteryx'' is an extinct
monotypic
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
euornithean dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...
s that lived during the
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...
, around 80
mya, in what is now the
Sierra Barrosa in northwestern
Patagonia
Patagonia () is a geographical region that includes parts of Argentina and Chile at the southern end of South America. The region includes the southern section of the Andes mountain chain with lakes, fjords, temperate rainforests, and glaciers ...
,
Argentina
Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...
. About the size of a chicken, it is the earliest known unequivocal example of secondary
flightless
Flightless birds are birds that cannot fly, as they have, through evolution, lost the ability to. There are over 60 extant species, including the well-known ratites ( ostriches, emus, cassowaries, rheas, and kiwis) and penguins. The smal ...
ness: its skeleton shows clear indications that the ancestors of ''Patagopteryx'' were flying animals, though other studies find earlier diverging theropods to be secondarily flightless.

Located in strata of the
Santonian
The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya ( million years ago) and 83.6 ± 0.7 m ...
Bajo de la Carpa Formation, the original remains were discovered by Oscar de Ferrariis, Director of the Natural History Museum of the
Comahue National University in
Neuquén
Neuquén (; ) is the capital city of the Argentine province of Neuquén and of the Confluencia Department, located in the east of the province. It occupies a strip of land west of the confluence of the Limay and Neuquén rivers which form t ...
around 1984–5. He passed them onto noted paleontologist
José Bonaparte, who described the
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
''Patagopteryx deferrariisi'' in 1992.
Characteristics
''Patagopteryx'' had feet with fused bones, much like modern birds. The animal did not have a
furcula (wishbone), meaning it could not have had the muscles necessary for flying. The legs had very short femurs, characteristic of a running animal. The second toe had a curved
claw
A claw is a curved, pointed appendage found at the end of a toe or finger in most amniotes (mammals, reptiles, birds). Some invertebrates such as beetles and spiders have somewhat similar fine, hooked structures at the end of the leg or Arthro ...
, but it does not appear to have been used as a weapon. It was
omnivorous
An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...
, and probably traveled in flocks across the plains of South America.
References
{{Taxonbar, from=Q2056622
Euornithes
Late Cretaceous dinosaurs of South America
Cretaceous Argentina
Fossils of Argentina
Bajo de la Carpa Formation
Fossil taxa described in 1992
Taxa named by José Bonaparte