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RE: Rahonavis; sickle claws

At 13:33 26-11-2001 -0600, you wrote:

Seriemas (_Chunga_ and _Cariama_) do have a sickle-claw on the second toe. So do certain phorusrhacids (e.g. _Psilopterus_). Cariamids and phorusrhacids are gruiform birds, so the presence of an enlarged sickle-claw may be a shared derived feature.

But seriemas have curved claws on pedal digit III and IV too. Anyway, this can be quantified with methods such as used by Feduccia (1993) and Ostrom (1969). So, what is the difference with regard to size and degree of claw arc curvature between digit II and the others in seriemas?

Feduccia, A. (1993). Evidence from claw geometry indicating arboreal habits of Archaeopteryx. Nature 259: 790-793.

Ostrom, J. H. (1969) Osteology of Deinonychus anthrhopus, an unusual theropod from the Lower Cretaceous of Montana. Peabody Museum of Natural History Bulletin 30: 1-165.