STL Science Center

STL Science Center

31 October 2012

More To Those Hands?

Illustration of type specimen
The gracile hands of Chirostenotes are of importance to the genus not just because they are what the initial description of the species was based off of, but also because those hands are, themselves, quite spectacular appendages. The hands that were found were basically complete and articulated; digit three was missing a few of the metacarpals, however, even that small deletion in the articulation laid out a unique and interesting manus to study. Comprised of digits 1-3 the hand was elongated, and ended in short, but substantial, claws that curved down and backward slightly. Most images show the hands being held with fingers splayed, palm surface facing medially, toward the center of the body. Many images, due to the current theory of feathering within the Oviraptorosaurids and Dromaeosaurids as well, show the wrists covered in feathers and the fingers are covered to the claws in what appears to be a soft down in most of the illustrations that are available. The hands being gracile is as important as the length of the fingers are to the animal. Gracility, or agility, in the fingers of Chirostenotes is essential for the theory of omnivorous behavior. Agility in the hands of Chirostenotes allowed for easily capturing small fast moving mammals and lizards in addition to also allowing for reaching for those animals in smaller areas than the stubby toothless beak of the animal would be able to probe; the beak of Chirostenotes would not be able to probe very far into any small areas at all actually, given the rounded and short structure of the actual beak itself. This toothless beak, coincidentally, has not been found whole yet, only as assorted top and bottom cranial/jaw elements.

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