The fossil belonged to a chick that was part of a group of ancient birds called Enantiornithes
To be exact, scientists have placed the baby bird as a member of the enantiornithes, a major group of birds that existed in the Cretaceous period some 145.
This reinforces the idea that enantiornithes birds hatched from the egg ready to fly.
Other Mesozoic groups like Enantiornithes
, which had teeth and clawed wings, are not thought to have left any living descendents.
The bird, part of an extinct group called Enantiornithes, was found inside an early Cretaceous winged theropod called Microraptor gui.
The fact that Enantiornithes are largely viewed as arboreal animals doesn't mean that they didn't frequent the ground - like most living arboreal birds, from parrots to woodpeckers," the New Scientist quoted Luis Chiappe at the Natural History Museum of Los Angeles County as saying.
Las Hoyas has yielded a high diversity of Enantiornithes
In fact, in pre-Campanian outcrops only a handful of specimens belonging to basal birds, such as Enantiornithes and primitive ornithuromorphs were recovered from distant localities of Brazil and Argentina (CHIAPPE & CALVO, 1993; ALVARENGA & BONAPARTE, 1992; ALVARENGA & NAVA, 2005; AGNOUN et al.
Enantiornithes and basal Ornithurae) are represented by less than 20% (HOPE, 2002).
Ornithothoraces is the clade formed by Enantiornithes and Ornithuromorpha+Ornithurae (CHIAPPE & CALVO, 1993).
In Enantiornithes the omal extremity of the coracoid is columnar and lacks any sign of a triosseal concavity; moreover the triosseal canal in these birds was surrounded in a larger extent by the scapula rather than the coracoid (WALKER, 1981; CHIAPPE & WALKER, 2003).
The phylogenetic position of the Cretaceous birds of Argentina: Enantiornithes
and Patagopteryx deferrariisi.