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.
Taphonomy of Isisfordia duncani specimens from the Lower Cretaceous (upper Albian) portion of the Winton Formation, Isisford, central-west Queensland
Taphonomic analysis of fossil material can benefit from including the results of actualistic decay experiments. This is crucial in determining the autochthony or allochthony of fossils of juvenile and adult Isisfordia duncani, a basal eusuchian from the Lower Cretaceous (upper Albian) distal-fluvial-deltaic lower Winton Formation near Isisford. The taphonomic characteristics of the I. duncani fossils were documented using a combination of traditional taphonomic analysis alongside already published actualistic decay data from juvenile Crocodylus porosus carcasses. We found that the I. duncani holotype, paratypes and referred specimens show little signs of weathering and no signs of abrasion. Disarticulated skeletal elements are often found in close proximity to the rest of the otherwise articulated skeleton. The isolated and disarticulated skeletal elements identified, commonly cranial, maxillary and mandibular elements, are typical of lag deposits. The holotype QM F36211 and paratype QM F34642 were classified as autochthonous, and the remaining I. duncani paratypes and referred specimens are parautochthonous. We propose that I. duncani inhabited upper and lower delta plains near the Eromanga Sea in life. Their carcasses were buried in sediment-laden floodwaters in delta plain overbank and distributary channel deposits. Future studies should refer to I. duncani as a brackish water tolerant species.
Antarctic dispersal routes, wandering continents and the origin of Australia's non–passeriform avifauna
In 1858, P. L. Sclater recognized Australia on the basis of its living avifauna, as a unique biogeographic unit, distinct from the Oriental fauna that characterized the Asian mainland. These two faunas complexly intermingle on the islands of the Indonesian archipelago, a situation reflected not only by the birds but by other vertebrate and invertebrate groups as well. A. R. Wallace in a number of papers (1863, 1869, 1876) initially described the avifaunas he encountered in this transitional zone; his work was followed by numerous refinements (Stresemann, 1927-34, 1939-41; Rensch, 1931) culminating with those which led Mayr (1941, 1944a-b, 1945a-b, 1972) to conclude that the major part of Australia's avifauna was derived from Southeast Asia. Although Darling-