Gallornis

Gallornis is a genus of prehistoric bird from the Cretaceous. It is of fairly indeterminate age and extremely fragmentary.

Overview
Yet it provides a tantalizing glimpse at an apparently crucial point in avian evolution. The single known species Gallornis straeleni lived near today's Auxerre in Yonne département (France); it has been dated very tentatively to the Berriasian-Hauterivian stages, that is about 140-130 million years ago.[1]. The material consists of

"a very worn proximal end of a femur and a humerus fragment"[2]

This is a highly significant taxon for theories about the evolution of birds, less well-known but certainly equal in importance to the famous Archaeopteryx. Unfortunately, it is not known from much or well-preserved material. What can be said is that the remains show features only known from the Neornithes - the group of birds that exists today. Thus, Gallornis demonstrates that as early as about 130 million years ago or more the ancestors of all living birds might already have been an evolutionary lineage distinct from the closely-related Hesperornithes and Ichthyornithes (essentially modern birds retaining some more ancient features like teeth) and the more distantly related Enantiornithes (a group of "dino-birds" which were the most successful avians in the Mesozoic).

Ecology
During the time of Gallornis, its range was located around 30°N, north of the Tropic of Cancer aridity belt. However, the Cretaceous was a hot and humid age in general, so the habitat might have more resembled West Africa around the Gulf of Guinea. Higher sealevels had large parts of Europe submerged for much of the time, and Southeast Europe and Asia Minor had not even attached to that continent yet (see also Haţeg Island, Haţeg Basin). The Alpide orogeny (the uplift of the Eurasian latitudinal mountain belt) had not even gotten underway.

Gallornis was a contemporary of many (non-avian) dinosaurs living around the (Second) Tethys Sea. In the archipelago that was then Europe, huge sauropods appear to have been the dominant herbivores.[3] Apart from some early birds, pterosaurs roamed the skies of the European microcontinents[4] (more abundant and diverse than the few birds[5]), while semi-aquatic[6] and finned marine crocodilians[7] were common. Herds of Iguanodon must have been a common sight. Stegosaurs were apparently rare and might have been Huayangosauridae.[8] Heterodontosauridae like Echinodon were contemporaries of this early bird, and part of the lineage which much later gave rise to Triceratops, while the ancestry of the famous Tyrannosaurus rex was still mid-sized long-armed animals like Eotyrannus lengi, which almost certainly lived when Gallornis was already extinct.