 |
| Notice the fearful claws & and the murderous look in his eye? Black-capped Chickadee photo by Eric Bégin. |
Yesterday, as I pulled out of the garage, something in the
driver’s side view mirror caught my eye. A fuzzy ball of black and white—a bit
larger than a prickly gumballs—came crashing down from the sweet gum tree. Then the ball broke apart into at least three Carolina Chickadees. They rolled on the ground,
kicking, punching, and talking about each other’s mommas.
I recently attended a presentation by David Peters about the
evolution of birds, sponsored by Webster Groves Nature Study Society, St. Louis Audubon and Eastern Missouri Society for Paleontology. The boundary of the
Cretaceous and Jurassic is not my area, so most of what was said went right
over my head. I apologize in advance for the mistakes I'm about to make. Peters’ theories about the taxonomy of pterosaurs is somewhat
controversial; again, for reasons that are beyond me. His website is fascinating. He explained how the shoulder (coracoid bone) and fused clavicles (furcula, or wishbone) allowed the arm/front leg of a reptile to become the
abducted, elongated wrist/claw/wing of a pterosaur.
 |
| Largest pterosaur, by Mark Witton |
Now I hadn’t really thought of pterosaurs as the direct
ancestors of birds. They looked like bats to me. I didn’t realize they had the modified scales we call
feathers. Think of Quetzalcoatlus—the largest pterosaur, with a 40-foot wingspan, a spear-shaped head, and a ring finger that
functioned as the wing. It looked even less like a bird when Peters analyzed
the fossils of its tracks, demonstrating that it walked on its wings/knuckles
like a reptile walks with its front limbs.
When he showed Nemicolopterus crypticus, another
pterosaur with a wingspan roughly the same as a chickadee’s, I began to see the
family resemblance. The ruckus under the sweet gum makes more sense now that I no longer see them as charming chickadees, but tiny, terrible, pterosaurs.
Thanks to Eric Bégin and Mark Witton for licensing their photos with Creative Commons.
You might also enjoy:
 |
| For a Few Bags of Gumballs |
 |
| When Butterflies Attack! |
I didn't know that there were pterosaurs that were so small -- I thought they were all huge, soaring beasts. Interesting!
ReplyDeleteI'm with you--thought all of these ancient beasts were the size of football stadium.
ReplyDeleteHi Anne,
ReplyDeleteThanks for the shout-out: really appreciated. Glad to hear you find pterosaurs as exciting as I do! Note that Nemicolopterus is almost certainly a hatchling pterosaur: adult members of its species probably span almost 2 m. Also, as you indicate, it's worth balancing DP's ideas with those of the rest of the pterosaur community: you may want to check out Pterosaur.Net for a more 'typical' view of the flying reptiles.
Mark Witton
Thank you for your kind words, Anne. You mentioned, "Now I hadn’t really thought of pterosaurs as the direct ancestors of birds." Pterosaurs are not related to birds. Birds descended from theropod dinosaurs. Pterosaurs from lizards.
ReplyDeleteDr. Witton may be correct about Nemicolopterus as a juvenile. However, it's impossible to tell at that size because, as embryo pterosaurs demonstrate, juveniles were virtually identical to adults. On the other hand, at the base of every major pterosaur clade is a series of gradually decreasing and then increasing pterosaurs, some shrinking to the size of hatchlings. So Nemicolopterus, although surrounded by larger specimens in the pterosaur family tree, may be an adult. Also the "typical" view of the flying reptiles is filled with problems, hence the genesis of my blog against their misinformation: www. pterosaurheresies.com