In this final AMNH lab we will look at the rest of the saurischian dinosaurs: the Carnosauria and Coelurosauria. Cladograms are provided below and are also in the exhibits.

For each of the 2 cladograms suppied below (Figure 1):

1. Identify the synapomorphies on the cladogram.
2. Draw this character as it is found in one taxon that contains it.
3. Place these shared derived characters in their functional and ecological context.
4. Identify the autapomorphies (unique derived characters) for each taxon on the cladogram.
5. Draw the autapomorphies for each taxon.
6. Place these unique derived characters in their functional and ecological context.
7. Compare the appearance in time of each taxon with their position on the cladogram. Are any apparently out of order?
Systematic Position of Tyrannosaurus
Examine the metatarsals of Tyrannosaurus, Struthiomimus, Allosaurus, Albertosaurus and Deinonychus, referring to the handout and the paper by Holtz*. Which show the arctometatarsalian condition? Compare it to the caldograms we have been using in class. Do you agree with the AMNH classification of Tyrannosaurus and Albertosaurus as carnosaurs? Please explain your reasoning.
* Holtz, T. R. Jr., 1994. The arctometatarsalian pes, an unusual structure of the metatarsus of Cretaceous Theropoda (Dinosauria: Saurischia). Journal of Vertebrate Paleontology 14:480-519.

Figure 1: American Museum cladograms:


Figure 2: Drawings of primitive (normal) and arctometarsalian conditions.