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True to Life?

Profile

Species: albertensis, ambulator, gigas, laramiensis, lindoei, natator, tenuis
Range: Late Cretaceous to Eocene (Turonian-Thanetian, 94-56 MYA) from western North America, including Texas, Utah, Wyoming, Montana, Alberta, Saskatchewan, and Nunavut.
Size estimate: 5-12 ft length, 50-80 lbs
Discovery: Edward Drinker Cope, 1876
Classification: Sauropsida, Eureptilia, Archosauromorpha, choristodera, champsosauridae

True to Life?

Since no one has ever seen a living dinosaur, and the missing pieces of the fossil record withhold important clues to their appearance, no artistic representation of a dinosaur ever gets it 100% right. On top of that, new discoveries can change our ideas of extinct creatures drastically. So, how close does this sculpture come to what we know of the original animal?

• These animals may look just like crocodiles, but they’re much more distant relatives that simply followed a similar lifestyle. The biggest immediately visible difference with crocodiles is that Champsosaurus did not grow osteoderms on its back. Instead, skin impressions show that they bore much smaller round or rhomboid scales across most of their bodies, with the largest scales on their flanks decreasing in size the closer they grew to the animal’s midline. The Park’s sculptures probably exaggerate the size of their scales, but correctly do not give them crocodilian osteoderms.
• Most of Champsosaurus’ defining characteristics deal with the construction of the head. Both sculptures present a mixed bag on portraying their heads, with the one lying down doing the better job between the two. Champsosaurus’ head took on a flattened heart-like shape with a snout longer than half the total length of the skull but only a quarter of the snout’s width for nearly its whole length. In this way, it joins the same snouty league as gharials, spotted garfish, and anteaters. To illustrate how extreme this flattening could get, Champsosaurus’ eyes grew on the top of its head, but its ears ended up on the underside. The sculpture with its head resting on the ground has more of a heart shape than its compatriot, though both have thicker snouts than the animals they represent.

• As just alluded to, the eyes on these sculptures ended up in the wrong position. Situated on the top of the head, they faced dorsolaterally  (to the sides but slightly upwards as well) on the narrow base of the snout, meaning they should also be placed closer together than the eye is wide. Such a configuration makes them look almost cartoonish—ironic how the reality would have to look less realistic than the portrayal!
• Its nostrils present another off-the-wall feature: they both face forward on the tip of the snout. Some scientists hypothesize that this arrangement took advantage of the jaws’ length, allowing the animal to rest on the bottom of a body of water while it raised its head to act like a snorkel, though others observe that the neck lacked much mobility when it came to raising the head. Perhaps it simply rested at an angle or preferred to rest vertically in deeper water. Either way, it’s a real life Snork!! Though the nostrils of these sculptures do face forward, the width of the snout makes them look a little less like the original Champsosaurus model. In life, though separated internally by a thin wall of bone and cartilage, their external appearance may have made them look like a single combined hole.

• Champsosaurus teeth followed the general pattern visible in the sculpture that’s showing off its choppers. The teeth in the tip of the snout took on a slightly longer and narrower shape. Like gharials and other long-snouted fish-eaters, the tip of the snout featured a spoon-shaped “rosette” of teeth. Unlike these sculptures, Champsosaurus’ jawline proceeded in a straight line for its entire length, rather than ending in a slight downward hook as shown here.
• In general proportions and posture, the sculptures’ bodies represent Champsosaurus well. Aquatic life led these animals to take on a flattish, streamlined shape, and it seems that they had become so accustomed to the water that they lost features for coping on land. Though it appears that females bore more robust limbs for land travel, presumably so they could lay eggs, they would not have walked high like crocodilians and may have been limited to scooting around on their bellies as shown here.
• Size-wise, these sculptures portray the average size for most Champsosaurus species. One species, C. gigas, could grow twice as long.