Plateosaurus is one of the Earliest Dinosaur Species
Plateosaurus like many of the Triassic period dinosaur is often overlooked by dinosaur lovers. In this article however, we will focus on Plateosaurus and learn everything there is to know about this prosauropod including: what it looked like, when and where it was discovered and what this early dinosaur species fed on.
What is Plateosaurus?
Plateosaurus is a genus of plateosaurid dinosaur that is believed to have lived between 214 and 204 million years ago during the Triassic period. As an early type of sauropodomorph, Plateosaurus is most commonly referred to as being a prosauropod. To date there are two recognized species of Plateosaurus: Plateosaurus engelhardti and Plateosaurus gracilis. As one of the earlier specimens of dinosaur species, Plateosaurus has received a great deal of attention from paleontologists and historians alike as they seek to draw an accurate picture of some of the world’s earliest dinosaur species. Researchers have been able to determine that Plateosaurus was indeed an herbivorous dinosaur that had a body shape similar to most large herbivorous bipedal dinosaurs.
What Did Plateosaurus Look Like?
Plateosaurus is believed to have grown to anywhere from 16 to 33 feet long and weighed in at anywhere from 1,300 to 8,800 lbs. Plateosaurus was bipedal and had a long neck that was flexible enough to allow the small skull to reach higher growing vegetation. Where the neck of this dinosaur was somewhat slender, the body of Plateosaurus was stockier and tapered off in to a long and mobile tail. The hands of Plateosaurus were well developed for grasping vegetation so that it could be lowered to the mouth; however, it is important to notice that Plateosaurus also had particularly short arms. The short arms were carried closer to the body while the stronger hind legs would have been carried underneath the body with flexed knees as the Plateosaurus stood and walked on its toes. The longer and stronger back legs of Plateosaurus show that this creature was capable of moving at relatively fast speeds.
Plateosaurus had a long and narrow skull that lacked some of the bulk that is often found in later dinosaur species. This long skull features a number of fenestrae that were designed to help lighten the load of the skull. The teeth that sat within the skull were socketed teeth and shaped like small leaves with approximately thirty teeth per jaw. While these jaws were utilized for feeding on vegetation, there is no doubt that when needed Plateosaurus would have been able to give a rather painful bite.
The Discovery of Plateosaurus
The first specimen of Plateosaurus to be discovered was found in 1834 by physician Johann Friedrich Engelhardt. Engelhardt made his finding at Heroldsberg near Nuremburg, Germany and while significant the pieces he discovered consisted only of some vertebrae and some leg bones. It would not be until three years later that these specimen pieces would be identified as bones from a new genus named Plateosaurus. The identification was made by German paleontologist Hermann von Meyer. While the initial discovery of Plateosaurus may have been slightly less impressive, since then many more discoveries of Plateosaurus specimens have been found. It is estimated that to date more than one hundred individual specimens of Plateosaurus have been recovered at various dig sites.
A large number of the identified Plateosaurus specimens have been located in Germany, Switzerland and France, not only are these areas significant because of the sheer number of specimens that have been yielded but also because of the quality of the specimens recovered here. Two locations of particular interest when it comes to the recovery of Plateosaurus specimens have been Saxony-Anhalt and a quarry in Trossingen in the Black Forest. Both of these two locations have yielded a high volume of Plateosaurus specimens.
Plateosaurus as the First Prosauropod
While the term “prosauropod” is often utilized in reference to Plateosaurus, researchers tend to prefer the use of the term “basal sauropodomorph.” Regardless of which term is utilized however, both tend to imply the nature of Plateosaurus as one of the first dinosaur species. As a genus, Plateosaurus consists of two species, the type species: Plateosaurus engelhardti and Plateosaurus gracilis. A number of other synonyms currently exist for Plateosaurus however including: Dinodosaurus, Gresslyosaurus, Pachysaurops, Pachysaurus, Pachysauriscus and Sellosaurus.
The Question of Posture and Gait
One of the more questionable aspects of Plateosaurus is just how this dinosaur stood and walked. Without a living specimen to view in the flesh as it were, it is difficult to determine how this early species stood and moved. There have been a number of theories as to how Plateosaurus locomoted with suggestions including: hopping like a kangaroo, walking on the hind legs and walking on the four legs with the appendages sprawled out. As an increasing number of dinosaur specimens were discovered however, researchers were able to get a more accurate picture of how the Plateosaurus moved. By studying other specimens of dinosaur species it was concluded that Plateosaurus was a bipedal dinosaur that held its forelimbs underneath its body. Some question still existed as to whether Plateosaurus was like some of the other herbivores discovered later that were able to interchange bipedal and quadrupedal motion. It was later realized that due to the position of the digits on the forelimbs, that Plateosaurus would have been unable to move quadrupedally at all.
What Did Plateosaurus Feed on?
The jaws of Plateosaurus are so similar in structure to many of the later herbivore species that there seems to be no doubt that Plateosaurus was a plant eater. Interestingly however, the tooth structure of the Plateosaurus is similar to some omnivorous species as well which could indicate that this species was not exclusively herbivorous and also fed on insects and small creatures or carrion.
The Lifespan and Growth Rate of Plateosaurus
Plateosaurus had a growth pattern similar to the giant sauropods that were seen later in the Jurassic times. As the Plateosaurus first began to grow it grew quickly until it hit sexual maturity at which point growth slowed down but continued far past the point of sexual maturity. The final size of fully matured and fully grown Plateosaurus varied and is believed to have been determined by multiple factors such as the availability and type of food sources available. The final size of a Plateosaurus was not determined by a general size determination since some Plateosaurus were found to be fully grown at 16 feet long and others continued to grow as large as 33 feet long. What can be determined by the growth rate of Plateosaurus however is that it was an endothermic creature, one of the first known. In addition to the growth rate of Plateosaurus, another indication that suggests that this creature was endothermic is the structure of the lungs. The Plateosaurus lung system seems to have been avian like with air sacs.
By studying the many Plateosaurus specimens recovered to date with some knowledge of the growth patterns that they went through, researchers are able to estimate the lifespan of these early dinosaurs. Being able to determine just how old a specimen was at the time of its death is a helpful piece of information in that it not only gives us an idea of lifespan but it also shows that these dinosaurs followed no specific growth rate. By analyzing the remains of a number of Plateosaurus specimens Martin Sander and Nicole Klein of the University of Bonn were able to determine that while some specimens of Plateosaurus were fully grown by twelve years old, others were not. In fact Sander and Klein found that some specimens were still growing by the age of twenty and a single specimen was found to still be growing particularly rapidly when it died at the age of eighteen. Of all of the specimens of Plateosaurus recovered, the oldest Plateosaurus specimen to be recovered is said to have been twenty seven years old at the time of its death. Even at twenty seven this specimen is still observed to have been growing. It is possible that this older specimen of Plateosaurus was an anomaly however, since the majority of specimens of Plateosaurus found to date seem to be aged between twelve and twenty years old. It is particularly difficult to put a lifespan on these dinosaur species however, since all specimens found to date appear to have died as the result of accidents and not as a result of old age.
What Can Plateosaurus Tell Us?
Plateosaurus may not be one of the most interesting dinosaur species and it certainly isn’t the largest or the fiercest, but this dinosaur can teach us a lot about the evolution of dinosaur species. As a dinosaur of the Triassic period, Plateosaurus is one of the first dinosaur specimens to have developed. It began the steady stream of sauropodomorphs that began in the middle Triassic period and continued late in to the late Cretaceous period, including some of the largest dinosaur species that the world had ever seen.