Wednesday, March 12, 2008
First of all, a thousand thank-you's to everyone who commented on my previous attempt at Nyctosaurus. Your comments on the post itself, as well as your emails (which, in some cases, included the relevant literature) helped to improve my understanding of this strange pterosaur a million times over. Perhaps of most help, however, were the skeletal drawings of Nyctosaurus by Chris Bennett and John Conway, accessable here and here. John Conway is some kind of god among paleo-artists; his measured drawings are, dare I say, authoritative. Bennett's picture is initially comical until you realize the ridiculous length of the wing metacarpal. Here are some things I learned while re-drawing Nyctosaurus based on various sources:
1) I knew that Nyctosaurus had lost its first three fingers, but I didn't realize that it had lost the first three metacarpals. In their place are ossified tendons which (as far as I can tell) ran from the pteroid to the distal tip of the fourth metatarsal.
2) Nyctosaurus has ridiculously short legs, or perhaps ridiculously long arms. Bennett's restoration of a vertically-oriented "naked lizard" is very nearly required for this beastie to shamble about on the land. This was clearly not an animal that spent a lot of time on the ground. Still, Chris' picture cannot be "final," because the amount of weight in front of Nyctosaurus' chest in an upright stance would cause it to constantly tip forward.
3) In attempting to figure out a more traditional quadrapedal posture, I kept the feet on the ground and angled the body upward in such a way that the ridiculously long arms could touch the ground without lifting the hindlimbs off the ground. Even in the resulting position, however, I am stupified as to how the creature moves forward.
4) The possibility exists that Nyctosaurus kept its arms in a sprawling posture while on the ground, so that more distance existed between its knuckles than between its feet, but this would make for a very wobbly structure, especially with that enormous head.
5) Look at the size of that freaking head! It's not enough that the skull is twice the length of the body, but the crest is almost three times the length of the skull! While sketching the whole animal (crest and all), I began to wonder if maybe the crest grew to such an extreme size to counterbalance the enormous head.
6) Nyctosaurus only has three wing phalanges, and the third phalange is strongly bent, like a very wide "V." Intuition tells me that this indicates a narrow cheiropatagium, perhaps terminating at the knee. Conway's illustration has the cheiropatagium terminating at the back of the ribcage, but somehow that just looks "wrong" to me. Personal preference, I admit.
I am still unsure of how to restore the "knuckle." An epidermal pad is still attractive, but wouldn't a tough pad like that interfere with the folding and unfolding of the wing finger? But if Nyctosaurus just had a tough knuckle, wouldn't the forelimbs be unsteady on the ground? And I apologize for the sketchy feel of this picture, but it really is just an inked sketch. I drew it this morning during my meds routine and thought it was good enough to not immediately crumple up. Rough though it may be, I feel it's a marked improvement over the last draft, because it incorporates many more reference materials.
Again, comments (no matter how severe!) are always welcome. And for that crest...I think I'm gonna need a bigger canvas!