Heilmann's Climbing-Wing


Two S. heilmanni chicks confront an Eomaia scansoria

Scansoriopteryx heilmanni
(Czrkas and Yuan, 2002)
 
   The Yixian fauna of early Cretaceous China includes many strange creatures, but few are as odd as Scansoriopteryx heilmanni.  These little dinosaurs are basal maniraptors, part of that large and diverse group that includes a variety of terrestrial dinosaurs as well as birds.   S. heilmanni is, indeed, very birdlike, with long arms, a lightly-built skeleton, and reversed fourth toes that allow the little animal to grasp branches.  These features are useful for S. heilmanni because, as its generic name suggests, this dinosaur is a climber, using its grasping feet and large hands to skitter up tree trunks and across branches.  

    As admittedly odd as S. heilmanni's arboreal tendencies are, its fingers are by far the strangest features of this little enigma. Rather than the normal maniraptor pattern of short first finger, longest middle finger, and slightly smaller third finger, S. heilmanni 's digits grow consecutively larger from first to third, with this last digit elongated into a thin, pick-like instrument that extends far beyond the tip of the middle finger.  This arrangement allows S. heilamanni to reach and grasp objects without dissaraying the feathers supported by its middle finger (Pharris), and also may be useful for prizing tasty grubs from their homes under bark or leaf mold.  As S. heilmanni is known only from a juvenile specimen, it is impossible to tell whether its odd fingers are a permanent feature, or whether they grow to normal proportions by adulthood (Brusatte).


Thanks to Nick Pharris, Steve Brusatte, Richard W Travsky, Rob Gay, Kris, and Brett Booth for helping me think about the possible uses of Scansoriopteryx 's weird third digit.
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© Daniel Bensen 2002
This image modified by Adobe Photoshop
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