GEOL 104 Dinosaurs: A Natural History
Smithsonian Dinosaur Exhibit Worksheet

Due Nov. 22

In class you have seen many slides of dinosaur skeletons, and seen a cast or two of fossils.  Now is your chance to see the real thing: actual dinosaur bones.

The Smithsonian Institution’s National Museum of Natural History (NMNH) has one of the largest collections of dinosaur and other fossils in the world.  Some of the best specimens from this collection are on display in the Dinosaur Hall.  This worksheet is to help guide you through the hall to see some of these specimens on display.

The Smithsonian museums are free; hours for the NMNH are 10 am to 5:30 pm 7 days a week.  You can take the Metro from the College Park Station to any of a number of stations near the Museum (now that the center of the Green Line is complete, the quickest route is College Park to Archives/Navy Memorial: you don’t have to change trains, and the NMNH is just on the other side of the Archives Building).

There is a lot of construction going on inside the NMNH, including some in the Dinosaur Hall itself.  Even so, there is still a lot of interesting things to see.

For this exercise you may wish to bring along the various dinosaur cladograms handed out in class.  You may work in teams; however ALL WORK YOU TURN IN MUST BE YOUR OWN.   (I have caught and reported a number of students in the past you have cheated by copying each other’s work: please don’t make me do that again…).

This package works as sort of a self-guided tour.  It will start you in one corner of the exhibit, have you walk around the main island, and then have you come back and eventually move upstairs.
So, let’s get yourself oriented:  Enter the main Dinosaur Hall, and take the right path (the side with the model of the Stegosaurus).  Follow the railing of the central “island” (the group of skeletons in the central region), passing some sauropods, Stegosaurus, and Allosaurus, until you are facing a pair of pelves.

1) On this exhibit, the distinctive pelves of saurischians and ornithischians are compared.  Which dinosaur genus is used to demonstrate the saurischian pelvic condition?  Which the ornithischian condition?
	Saurischia:

	Ornithischia:	

2) A little further along this railing and you come to some non-dinosaurian amniotes.  One of these is Trilophosaurus, a quadrupedal reptile.  What about the posture of its limbs shows that it is NOT a dinosaur?

Although there are lots of interesting things in the other parts of the paleontology exhibits (for example, some fine specimens of the 1st and 2nd amniote radiations), head back to the main Dinosaur Hall.

3) Find the Allosaurus fragilis skeleton.  Examine its left scapula.  In a normal individual this bone has a simple strap shape.  Draw the bone as it is in this specimen.

What do you think might have happened to this bone?  Note that the real ribs of this specimen (which are in the collections rather than on display) are damaged along the left side, and the left dentary was so damaged and rehealed in such an unusual way that it was thought to be from a whole new dinosaur (named “Labrosaurus”).

Extra Credit) Allosaurus is a [ herrerasaurid  |  ceratosaur  |  carnosaur  |  coelurosaur  ].

4) Move down to the skeleton of the Stegosaurus.  Compare it to the life sized model of the Stegosaurus.  How well does the model match the dimensions of the fossil?  For example, compare the size of the skull, neck, and feet of the real fossil to those of the model.

Extra Credit) How many pairs of spikes in the Stegosaurus thagomizer?			

5) Compare the skulls of the macronarian Camarasaurus and the diplodocoids Diplodocus.  How do the teeth differ between the two?  How do the nares differ between the two?

6) Some of the dinosaurs (PLEASE, I am not interested in non-dinosaurs here!!) in the main Dinosaur Hall are shown in “death position” (that is, the skeletons are mounted as they were found in the rock, rather than the position they would have in living animals).  Two are in the central “island”, and one is up on one of the walls.  Which dinosaur is shown here in death position?

This dinosaur is a(n) [ thyreophoran  |  theropod  |  sauropodomorph  | ornithopod ].

7) Almost all the dinosaurs in the central “island” are from the same Late Jurassic dinosaur-bearing formation of western North America.  Which formation is that?

8) Examine the cast of Tyrannosaurus rex.  Cool, isn’t it?  Other than size, list three anatomical differences between Tyrannosaurus and Allosaurus that you can see, with extra credit for a fourth:

Extra Credit) Tyrannosaurus is a [ herrerasaurid  |  ceratosaur  |  carnosaur  |  coelurosaur  ].
Move over past the steps to the other wall of the Dinosaur Hall.

9) The Marginocephalia exhibit is under renovation: when done, it will have the first cladogram in the Dinosaur Hall.  Until then, there are a couple of ceratopsian skulls available for viewing.  List the genus of a ceratopsian fossil skull (NOT the drawings on the wall) on display, and indicate if it is a ceratopsine (aka chasmosaurine) or a centrosaurine:

10) Thescelosaurus and Heterodontosaurus are both mounted on the wall near the future Marginocephalia exhibit.  These two dinosaurs are both representatives of:
[ Thyreophora  |  Sauropodomorpha |  Ornithopoda  |  Theropoda  ] (Circle the correct answer).

Which of the two (Thescelosaurus or Heterodontosaurus) is larger?

Which of the two (Thescelosaurus or Heterodontosaurus) is older?

11) Move along to the hadrosaurids.  The complete skull of a hadrosaurine is on display.  What genus of hadrosaurine is there?

Extra Credit) The skull of a juvenile and the posterior half of a skeleton of an adult (including skin impressions!) of a lambeosaurine are on display.  What lambeosaurine taxon is this?

12) Pass the cast of the Tyrannosaurus rex skull, and move down the line.  Examine the skeleton of Ceratosaurus nasicornis.  This is the type specimen (the original one to which the name was assigned).  New research indicates that it wasn’t fully grown when it died.  How many fingers does Ceratosaurus have?  How does this compare to its contemporary rival, Allosaurus?

Extra Credit) Ceratosaurus is a [ herrerasaurid  |  ceratosaur  |  carnosaur  |  coelurosaur  ].

Turn around and face the main island.

13) What dinosaur is shown in death position at this point?  What features of the neck anatomy are shown here that are NOT shown on the mounted specimen of this dinosaur elsewhere in the exhibit?

14) Somewhat out of place on the central island (since they are not from the same formation as the others) are the eggs of Troodon and the baby Maiasaura skeleton.  Maiasaura is a hadrosaurine hadrosaurid.  However, does this hatchling specimen show the characteristic large nostrils and broadly expanded snout?

15) Look at the pair of skeletons of the primitive iguanodontian Camptosaurus.  Although they are labeled as separate species, these are almost certainly different growth stages of the same species (C. dispar).  What unusual feature do you see on the right ilium of the larger of the two Camptosaurus skeletons in the main island?

16) Examine the enormous skeleton of Diplodocus dominating the Hall.  Rank (from the longest section to the shortest section) each of the sections of the vertebral column (cervical, dorsal, sacral, and caudal):
	Longest:
	Second longest:
	Third longest:
	Shortest:

Extra Credit) Find the distal caudals of Diplodocus.  Circle whichever of the following is a better description of the anatomy of these bones:
I)	Very complex, with large transverse processes and tall neural spines
II)	Very simple, with not transverse processes and no neural spines

17) Find the enormous limb bone of Brachiosaurus altithorax on display (this is a specimen you can touch).  As precisely as possible, which bone is this?

Go back around to the other side of the exhibit, and take the stairs up to the upper deck of the Dinosaur Hall (near the pterosaurs and such). From the upper deck of the Dinosaur Hall, find the overlook and look down at the central island.  Look at the dinosaurs from above.  

18) Which dinosaurs tend to have narrower hip regions: carnivores or herbivores?  What reason might there be for this?

Turn around and look at the pterosaur exhibit.
19) List three genera of pterosaurs on display, with extra credit for a fourth.

20) Move over to the reconstructed skull of a Tyrannosaurus rex.  This particular cast spent most of the middle 1990s in the office of then-Speaker of the House Newt Gingrich, but now is (thankfully) available for everyone to see.  Find the posterior view of the skull.  Is the cranium wider than tall in the posterior section, or is it taller than wide?

21) Finally, walk up the ramp a bit.  Find the exhibit sign for the two wall-mounted specimens on the opposite wall.  Which two dinosaurs are on display there?  Indicate which one is in life position and which one is in death position (although at 90º from the original flat surface!)?

While you are in the museum, use your time to examine some of the other exhibits.