Acrylics and inks on cardboard.
Click here to see a close up of Deinonychus  

Our beloved and favourite sickle claw has come of age and I've decided to give him a new face lift.
Perhaps a painting like this can be accused of being pure,wild speculation.One of the facts of dinosaurology is that in dealing with bones "almost" exclusively, we sometimes forget that the external appearance of the animal could have been very outlandish indeed... just as the new discoveries in China are demonstrating (and I can tell you: there will be much more dramatic revelations in the future... some of them already being prepared and bound to revolutionise dinosaurology and paleontology... unfortunately formal description is still awaiting). Soft tissue can change the appearance of a creature in a very dramatic way, creating imposing displays and notable volumetric differences.

At a mechanical level, I have tried to re-interpret the Deinonychus hands using Alan Gishlick's (Yale University) new comparative studies of Archaeopteryx and Deinonychus' (wings). The hook-like, restricted movement function of digits one and two (no. two as feather-bearing one) contrast with a loose and opposable third finger (which explains the bent way it is usually preserved in several Archaeopteryx fossils. Quoting his own words:

"The transformation from grasping hand to wing while retaining functionality throughout the transition is one of the most persistent questions in the origin of avian flight. New data from hand morphology of basal maniraptorans provides insight into how this may have occurred. The third digit of Deinonychus antirrhopus (Ostrom) has a curious morphology: bowed gracile metacarpal, buttressed joints between the first, second and third phalanges so that they move as a single unit and the finger is held slightly flexed, and a 50 degree twist in the long axis of the finger so that the ungual (claw) faces medially. This morphology, shared by Archaeopteryx, Confuciusornis, Velociraptor, and possibly Protarchaeopteryx and Caudipteryx, allows for the third digit to cross underneath the second digit. I suggest that this unique hand allowed the semi-opposable first and third digits to retain their grasping ability while the feathers (originating from the second digit) were elongated. This allowed feathered maniraptorans to retain a functional grasping hand during the early development of a wing."

GISHLICK, ALAN D. 1999. "Functional morphology of the hand of Deinonychus antirrhopus and its importance for the origin of flight."

Since both Archaeopteryx and Deinonychus seem to have the same mechanism, it supports more than ever my suspicion that the hands of Dromeaosaurs are modified wings or simply specialised primitive wings-in-the-making (depending on our choosing of the Trees-Down or Ground-Up theory of the dinosaurian origin of Birds).

Personally I'm inclined to believe that the hands and fingers are free of feathers (that is the same as saying that I'm not in complete agreement with my own painting!), but this time I felt like supporting Alan's thesis and doing a reconstruction to show the possibility that they were feathered... Paleontology can be this fun!

And this is the result: ferocious-looking fighters just after killing their Tenontosaurus tilleti prey.

The location: Montana (U.S.A.), Early Cretaceous.

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