Showing papers on "Avialae published in 1991"
TL;DR: The anatomy of a new articulated enantiornithine bird skeleton from the Late Cretaceous of Patagonia clearly indicates a capacity for powered flight, approaching that of modern birds.
Abstract: The anatomy of a new articulated enantiornithine bird skeleton from the Late Cretaceous of Patagonia clearly indicates a capacity for powered flight, approaching that of modern birds. Enantiornithines possess some of the synapomorphies of the Ornithurae, although they retain plesiomorphic states for many other characters, mainly in the hind limb. Such a mosaic character combination suggests a sister-group relationship between Enantiornithes and Ornithurae. Derived features of the pectoral girdle are here considered as diagnostic for a major avian clade, the Ornithopectae, comprising all known birds other than Archaeopteryx. The combination of derived and primitive traits in the fore and hind limbs and their girdles in early ornithopectines reflects mosaic evolution, with flight-related modifications of the fore limb and pectoral girdle preceding those in the hind limb and pelvic girdle.
44 citations
1 Sep 1991
TL;DR: Features of the dentition suggest that L. estesi belonged within the troodontid dinosaur-bird clade and, less certainly, within the Avialae (Archaeopteryx plus all later birds) and may be the earliest avialan.
Abstract: Lisboasaurus estesi from the Upper Jurassic of Guimarota, Portugal was first described as an anguimorph lizard. Reexamination of the holotype and referred specimens leads to the conclusion that L. estesi represents a small archosaur. Features of the dentition suggest that L. estesi belonged within the troodontid dinosaur-bird clade and, less certainly, within the Avialae (Archaeopteryx plus all later birds). It may thus be the earliest avialan. A second species in the genus, L. mitrocostatus, is based on indeterminate material and is a nomen dubium restricted to the type specimen. -from Authors