Lambeosaurus was a Hollow-Crested Hadrosaur
Lambeosaurus, pronounced “LAM-bee-uh-SOR-us”, was a bipedal and quadrupedal plant-eating dinosaur from the hadrosaurid family that lived during the Late Cretaceous Period in North America. It is the largest known duck-billed dinosaur, but its most distinguishing feature is a hollow crest on its cranium. The name “Lambeosaurus” means “Lambe’s lizard”. It was named in honor of Lawrence Lambe, an early Canadian paleontologist.
|Prehistoric Era||Late Cretaceous|
|Weight||4 – 6 short tons (3.6 – 5.4 tonnes)|
|Length||40 feet (12.2 meters)|
|Height||20 feet (6.1 centimeters)|
|Maximum Speed||Approximately 28 MPH|
What did Lambeosaurus Look Like?
The large, hollow and bony crest on its head would probably be the first thing you’d notice. It also had a bulky body, weighing over 4 tons. It was about 40 feet long and 20 feet tall. It was quadrupedal, with four legs, but its hind legs were much bigger than its arms and paleontologists believe it would primarily walk and run on its stronger hind legs, as a bipedal dinosaur using its long tail for balance. As a duck-billed dinosaur, Lambeosaurus had a wide and toothless bill, but with teeth inside its cheeks. Lambeosaurus is one of the few dinosaurs that has fossilized soft tissue imprints, so we know that its skin had a thick, rough, and pebbly texture.
Physical Attributes of Lambeosaurus
The hatchet-shaped bony crest on this herbivore’s skull was as big, or even bigger than its head. Lambeosaurus’ nostrils went up through the crest and its snout was narrow, while its bill was wide and blunt. Based on the relative sizes of its brain and body weight, scientists believe that Lambeosaurus was probably of average intelligence.Researchers also know that its long tail was stiffened by ossified tendons. Studies also find that dome of the fingers on Lambeosaurus’ hands were bunched together, suggesting hooves, with one finger free for manipulating objects. There were three toes on each foot.
The Distinctive Crest
The hollow and bony crest of Lambeosaurus was hatchet shaped in fully grown male dinosaurs, and short and more rounded in the dinosaur specimens paleontologists interpret as females. The crest projected in front of the eyes and there was a bony rod that jutted out over the back of the head. There were two sections to the crest. There was the uppermost part, which was a thin coxcomb (similar to the male-specific growth on a rooster’s head) that grew in adulthood. The second section was the hollow part at the base of the crest that was a continuation of the nasal passages.
What was the Purpose of the Crest?
Paleontologists have put forth a few educated theories about the functions that the crest had for a Lambeosaurus. The hollow sections could have housed salt glands, which is a feature found on many animals that ingest saltwater. It is an organ for excreting excess salt. If Lambeosaurus needed to drink saltwater, that would have been a necessary organ. Other possibilities for the hollow section could be to produce sounds, attract mates, identify individuals in the species or to enhance the sense of smell. It seems especially likely that the cranialcrest played in to mating rituals since the feature was more pronounced on males. The consensus is that the function was social, so producing sounds and gender recognition are the frontrunner theories. If they did produce sounds, there would be different sounds produced depending on the gender of the dinosaur since the crest shapes were different. That would also help with gender recognition.
Strong Vision and Hearing in Lambeosaurus
The eye sockets of Lambeosaurus, like other hadrosaurids were large. They also had sclerotic rings, which are bone rings found in the eyes of vertebrate animals such as reptiles. To scientists, those features suggest that hadrosaurids like Lambeosaurus relied on their vision and were probably diurnal, which means they were active during the day and slept at night. There is also evidence that they had strong hearing. The related Corythosaurus had a sensitive middle ear and the Lagena, also a hadrosaurid, had a sensitive inner ear.
What did Lambeosaurus Eat?
Lambeosaurus was an herbivore. Given its skull shape it probably ate the leaves of flowering trees, twigs, and pine needles with a grinding motion similar to how mammals chew. Its cheeks contained dental batteries that each held over 100 teeth that were constantly replaced and only a few of which were in use at one time. Plant material was held in the side of its jaws, using an organ like a cheek, and it used its beak to crop plants. It fed at a height of 13 feet above the ground and lower.
How did Lambeosaurus Move?
Most dinosaurs are either bipedal or quadrupedal, but paleontologists believe that Lambeosaurus was both. A characteristic shared by other hadrosaurids. Lambeosaurus walked and ran swiftly on his relatively stronger hind legs. The shorter front legs were likely used for support when foraging on the ground for plants.
What kind of Environment did Lambeosaurus live in?
Lambeosaurus lived during the late Cretaceous period, about 76 to 75 million years ago. They were known to live in what is now known as the Dinosaur Park Formation. Many other popular dinosaurs have been discovered and documented as having lived in the area at various times, such as Chasmosaurus, Edmontonia, and other duck-billed dinosaurs like Gryposaurus. Experts believe that when Lambeosaurus roamed the Formation it was warmer than modern day Canada and conifers were abundant, along with tree ferns, ferns, and angiosperms – also called “flowering plants”.
Lambeosaurus and its Predators
As an herbivore, Lambeosaurus would have been susceptible to carnivorous predators. Lambeosaurus had strong hearing and sight, and fortunately it wasn’t the dumbest herbivore, but it didn’t have any other obviously effective defenses. Its best bet would have been to stick to its herd and run away in case of attack.
The Discovery of Lambeosaurus
When the first specimens of Lambeosaurus were discovered, they were attributed to different species. In 1902, Lawrence Lambe described some hadrosaurid fossils from Alberta, Canada as Trachodon marginatus. In the 1910s, paleontologists found other remains of hadrosaurids from the same area, which is now called the Upper Cretaceous Dinosaur Park Formation. Two more skulls were attributed to T. marginatus by Lambe, with the genus name described as Stephanosaurus, but there wasn’t enough information to put the new skulls with the earlier marginatus fossils. In 1923, paleontologist Williams Parks suggested a new genus and species for the fossils, but he named the generic and specific names in honor of Lambe, and called it Lambeosaurus Lambei.
It is common for paleontologists to change the attribution of species as more information becomes available or new paleontologists on the scene see the same fossils differently. That happened a lot with Lambeosaurus. The early paleontologists working in Alberta, Canada around the turn of the 20th century initially thought that the remains of juvenile Lambeosaurus were adults of the Cheneosaurinae line of hadrosaurids. It wasn’t until 1975, when Peter Dodson demonstrated that the “cheneosaurs” were the youth of other dinosaurs. Another dinosaur name, “procheneosaurus” – given to various specimens, is now thought to be a synonym for Lambeosaurus. In another case, in 1964 John Ostrom pointed out that an old species, called Hadrosaurus paucidens by Othniel Charles Marsh, was probably a Lambeosaurus specimen. An explanation for why there were so many species and genus labels used to describe Lambeosaurus fossils, in a short time frame and small area, was put forth by Peter Dodson in 1975. He studied and measured dozens of skulls and discovered that the fossils made more sense as juveniles or as the different sexes of the same species. For example, L. clavinitialis was probably a female of L. lambei and Corythosaurus frontalis and Procheneosaurus praeceps were probably juveniles of Lambeosaurus.
The Importance of Lambeosaurus
Lambeosaurus is important to paleontology because it is the largest known Hadrosaurid. It is also interesting for the fossilized skin casts that it left behind, giving us rare knowledge of its skin texture. There is also it’s distinctive hollow crest of Lambeosaurus which sparks the imagination of paleontologists who love solving mysteries about the dinosaurs they uncover.