Historical Ornithology 101
(via Tetrapod Zoology)
Diagnostic anatomical reconstruction of Deinonychus antirrhopus, intended loosely for Wikipedia but also as an experimental piece to show pretty much exactly how I believe this animal looked in life.
This was largely inspired by an interesting Facebook discussion with paleoartist Julius Csotonyi about arm-folding in paravian dinosaurs. It occurred to me that people seldom reconstruct paravians, particularly dromaeosaurs, with their arms folded in a reasonable and accurate way. Julius made the fair the point that these animals probably didn’t carry their arms out in front of the body, as is so often depicted (in skeletals and otherwise — it makes sense in skeletals, to adequately show the hand and arm anatomy), because such an awkward orientation would leave the hand and arm feathers open to damage and breakage. But they also can’t fold them tightly against the breast or back like birds do, because they lack the mobility to do so.
So how did Deinonychus normally carry its arms? Senter’s 2006 paper on forelimb function in Deinonychus and Bambiraptor shows that the humerus couldn’t rotate much past the horizontal with respect to the scapula. In addition, Sullivan et al. 2010 — winningly translated to layman coherency by Matt Martyniuk — shows that wrist mobility in many paravians is much less than you might expect, given their similarity to birds. The wrist of Deinonychus antirrhopus specifically would not have allowed it to bend its hands even 90° with respect to the arm!
Given these limitations, most of the flexion would have to occur at the elbow, but a fully flexed elbow would mean that the hands would be hanging below the body, not held sleek and secure alongside the body. The arm orientation in my illustration above is based on what I think is probably the perfect configuration for carrying the arms: a fully-flexed shoulder, a fully-flexed wrist, and a nearly fully-extended elbow. A few other people have drawn their dromaeosaurs with the same arm configuration, like Smnt2000 and Pilsator, so kudos to them.
When people tell me that T. rex can’t be scary if it isn’t restored as scaly, I laugh in their faces.
(Tyrannosaurus rex by John Conway)
"Stan" the life-sized Tyrannosaurus Rex replica skeleton stands covered in pink flamingos at the Googleplex in Mountain View, California. The dinosaur is intended to remind Googlers not to let the company fall behind the curve and become outdated.
The final photo is a pile of cement with flamingos in it placed under Stan’s tail—making it look like he has eaten and pooped out the plastic birds.
Ah, that’s who this guy is!
It’s hard to put a Protoceratops in a tree. It had taken Velociraptor nearly a half an hour to do so, tugging, pulling, hefting the heavy thing. The carcass was floppy and didn’t cooperate; the head shield got caught on a protrusion of bark; the limbs bumped and bounced against the tree like unsynced pendulums.
As soon as the dromaeosaur’s larder was filled—the dead Protoceratops balanced just right—the tarbosaurs came snooping. Dragging a dead dinosaur into a tree is not inconspicuous business, and the juveniles had heard and smelled enough to pique their curiosity and come trotting.
Velociraptor stared down at the two tyrannosaurs. It was safe—tarbosaurs couldn’t climb trees—but it was also stuck—tarbosaurs were excruciatingly patient (through juveniles admittedly less so than adults). They knew one bad tug from a misplaced bite might send the Protoceratops falling from the pantry. Or, if luck was particularly one-sided, the carcass and the Velociraptor could spill from the branch.
And so the three predators stared, occasionally pipping and fluting songs of aggression or ownership at each other, neither side backing away from the meal perched unsecurely in the tree.
A phylogeny of maniraptors - a gift for albertonykus for being awesome :D
Whipped up from recent avian phylogenies & Dr. Holtz’ Theropod cladograms. Green = extant lineages, brown = extinct. Yeah, the non-avian maniraptors are a little sparse, I apologize for that, but one of my main goals was to create a ‘consensus’ of multiple trees. The birds relationships are slowly stabilizing, but we have a long way to go.
Any inaccuracies or changes, please let me know.
Images from PhyloPic - http://phylopic.org/
I love this! You keep springing surprise gifts on me. XD
Tarchia & Tarbosaurus in the Hwaseong City Hall 1
Today in AP Bio we were talking about how some animals have anti-freeze compounds in their blood to keep them warm, and this kid just leaned over to me and whispered,