The imagery on this page is supporting material for a paper entitled Avian brain evolution: new data from Palaeogene birds (Lower Eocene) from England, by A.C. Milner and S.A. Walsh (2009, Zoological Journal of the Linnean Society 155:198-219). The abstract is as follows:

       Investigation of how the avian brain evolved to its present state is informative for studies of the        theropod–bird transition, and as a parallel to mammalian brain evolution. Neurological anatomy in fossil        bird species can be inferred from endocranial casts, but such endocasts are rare. Here, we use        computed tomographic analysis to determine the state of brain anatomy in two marine birds from the        Lower Eocene London Clay Formation of England. The brains of Odontopteryx (Odontopterygiformes)        and Prophaethon (Pelecaniformes) are remarkably similar to those of extant seabirds, and probably        possessed similar somatosensory and motor capabilities. Each virtual endocast exhibits a degree of        telencephalic expansion comparable to living avian species. However, the eminentia sagittalis (wulst),        a feature characteristic of all living birds, is poorly developed. Our findings support the conclusion        that much of the telencephalic expansion of modern birds was complete by the end of the Mesozoic,        but that overall telencephalic volume has increased throughout the Cenozoic through dorsal        expansion of the eminentia sagittalis. We suggest that improvements in cognition relating to        telencephalic expansion may have provided neornithine avian clades with an advantage over archaic        lineages at the Cretaceous–Tertiary boundary, explaining their survival and rapid diversification in the        Cenozoic.

This specimen, the holotype, was collected from the Lower Eocene (Ypresian) London Clay Formation of southeast England. It was made available to The University of Texas High-Resolution X-ray CT Facility for scanning by Dr. Angela Milner of the Natural History Museum (London) and Dr. Timothy Rowe of The University of Texas at Austin. Funding for scanning and image processing was provided by Dr. Milner and by a National Science Foundation Digital Libraries Initiative grant to Dr. Rowe.

This specimen was scanned by Matthew Colbert on 23 January 2003 along the coronal axis for a total of 1110 slices. Each slice is 0.101 mm thick, with an interslice spacing of 0.101 mm and a field of reconstruction of 49.0 mm.

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None available.