Fred Ruhe
Well-known member
Juan Benito, Bhart-Anjan Bhullar, David Burnham, Laura E. Wilson, Daniel J. Field, 2018
New specimens of the Mesozoic Ornithurine Ichthyornis
Progressive Palaeontology 2018 Abstracts Book
Free pdf: https://www.palass.org/sites/default...act book.pdf
Abstract: https://www.palass.org/sites/default...act book.pdf
The Late Cretaceous bird Ichthyornis dispar was one of the first known Mesozoic avialans, and is recognized today as one of the closest relatives of crown birds among Mesozoic stem birds. As such, the skeletal morphology of Ichthyornis may be more representative of the ancestral condition of modern birds than that of any other known Mesozoic avialan, and its study has crucial implications for understanding the origins and early evolution of crown birds. Previous work on Ichthyornis has largely been based on limited fossil material discovered over a century ago. Here we present high resolution scans of new, exquisitely preserved three-dimensional specimens of Ichthyornis from the Late Cretaceous of Kansas, focusing on the pectoral girdle and wing elements. The new specimens are more complete and in better condition than the classic material, and include some previously unrepresented elements, as well as better preserved examples of several bones. These include a complete, three-dimensionally preserved sternum, including robust caudolateral processes and relatively developed sternal incisures. The coracoid exhibits very large and recurved acrocoracoid and procoracoid processes, and the scapula preserves a robust and hook-shaped acromion process, differing from previously referred specimens. This last character is of particular interest, as it represents a previously described autapormorphy of Ichthyornis dispar. Wing bones, carpals and hand elements are well preserved as well, and include the first complete radiale known from Ichthyornis. Ongoing work in these and other new Ichthyornis specimens will shed new light across the proximal-most portion of the stem-bird phylogenetic tree.
Enjoy,
Fred
New specimens of the Mesozoic Ornithurine Ichthyornis
Progressive Palaeontology 2018 Abstracts Book
Free pdf: https://www.palass.org/sites/default...act book.pdf
Abstract: https://www.palass.org/sites/default...act book.pdf
The Late Cretaceous bird Ichthyornis dispar was one of the first known Mesozoic avialans, and is recognized today as one of the closest relatives of crown birds among Mesozoic stem birds. As such, the skeletal morphology of Ichthyornis may be more representative of the ancestral condition of modern birds than that of any other known Mesozoic avialan, and its study has crucial implications for understanding the origins and early evolution of crown birds. Previous work on Ichthyornis has largely been based on limited fossil material discovered over a century ago. Here we present high resolution scans of new, exquisitely preserved three-dimensional specimens of Ichthyornis from the Late Cretaceous of Kansas, focusing on the pectoral girdle and wing elements. The new specimens are more complete and in better condition than the classic material, and include some previously unrepresented elements, as well as better preserved examples of several bones. These include a complete, three-dimensionally preserved sternum, including robust caudolateral processes and relatively developed sternal incisures. The coracoid exhibits very large and recurved acrocoracoid and procoracoid processes, and the scapula preserves a robust and hook-shaped acromion process, differing from previously referred specimens. This last character is of particular interest, as it represents a previously described autapormorphy of Ichthyornis dispar. Wing bones, carpals and hand elements are well preserved as well, and include the first complete radiale known from Ichthyornis. Ongoing work in these and other new Ichthyornis specimens will shed new light across the proximal-most portion of the stem-bird phylogenetic tree.
Enjoy,
Fred
