An enantiornithine bird from the Lower Cretaceous of Queensland, Australia
Current classification of birds recognizes four subclasses: the Archaeornithes, the Enantiornithes, the Odontornithes and the Neornithes. Three of these subclasses were proposed during the nineteenth century, but the Enantiornithes was proposed only five years ago, based on material from the Lecho Formation (Maas-trichtian) of Salt a Province in Argentina1. Further material from Asia (Mongolia) and North America (Mexico) has been referred to the Enantiornithes2, all of it from the Campanian. Now, in addition, a small tibiotarsus found in the Lower Cretaceous (Albian) of Queensland not only represents the first bony material of Mesozoic birds from Australia, but is also the first reported occurrence of an enantiornithine bird in the Lower Cretaceous.
Palaeognathous bird from the Cretaceous of Central Asia
Two skulls of an unquestionably palaeognathous bird were found by the Polish–Mongolian Palaeontological Expedition to the Gobi Desert1. Both specimens originate from the same locality, the beds being referred to as Barun Goyot Formation (?Campanian2). One skull, badly damaged, has been described as Gobipteryx minuta and the new order Gobipterygiformes has been allocated tentatively to the Palaeognathae3. Examination of the second, better preserved, although incomplete skull has now confirmed this allocation. Thus, Gobipteryx is the oldest known palaeognathous bird, the earliest hitherto recorded fossils of this group being of Eocene age4. I estimate the skull of Gobipteryx to be 45 mm long, so that the bird was roughly the size of a partridge.
Changing Continental Arrangements and the Origin of Australia's Non-Passeriform Continental Avifauna
Classically the origin of Australia's avifauna has been sought in south-eastern Asia with the Malay Archipelago serving as the only link between two major biogeographical realms. During the past two decades however, developments in the geological sciences have suggested strongly that the Australian continent has not always been where it is today with respect to other land masses. In fact, as little as fifty million years ago it was close to, if not directly connected with, Antarctica, which in turn probably was joined to South America by an archipelago. Contemporaneously, milder climatic regimes dominated Antyctica, supporting a diverse flora that included forests of podocarps, other conifers and Nothofagus. Certsunly this possible austral dispersal roufe, as well as the Indonesian archipelago, needs to be kept in mind in future considerations of the Australian avifauna's origin, specially for its distinctive groups such as emus, cassowaries, megapodes, pigeons and parrots among others.