In this article we will no doubt talk about one of the most harmless dinosaurs that could ever exist. It had to literally run for its life and had no way to defend itself. Read on to learn more about this dinosaur.

What does the name Dryosaurus mean?

The meaning of this name is “oak dinosaur”, the name comes from the Greek terms δρυο/dryo which means “oak” and σαυρος/sauros which means “lizard”.

History of the Dryosaurus discovery

The year 1876 passed when paleontologist Samuel Wendell Williston discovered the fossils of what would become ornithopods in Albany County, Wyoming.

Later, in 1878, Professor Othniel Charles Marsh described the remains and named it first as a new species: Laosaurus altus.

The term “Altus” referred to the fact that this was a taller species than the already known one: Laosaurus celer.

Marsh would later classify it as a separate genus in 1894, calling it Dryosaurus; a name designated to refer to what would become its forest life.

Although it was later learned that the name referred to the oak leaf shape of its cheekbones.

From what we originally knew as Laosaurus altus, it was renamed Dryosaurus altus.

The fossils of this dinosaur were found in the Morrison Formation, in the layer that dates back to the Titonian.

The find consists of a complete skull and lower jaw.

More fossils have been found over time, such as the back of a skeleton, a partial skeleton without a skull, the back of a skeleton…among others.

From these multiple fossil discoveries, other species have been named besides Dryosaurus altus,

The first of these was created accidentally when in 1903 Giuseppe de Stefano renamed the Crocodilus phosphaticus as Dryosaurus phosphaticus; he intended to call it Dyrosaurus phosphaticus. Eric Buffetaut modified it in 1981.

The species D. lettowvorbecki first described in 1919 by Virchow, its name refers to the German military man Paul von Lettow-Vorbeck.

The fossil remains were found in Tanzania and consist of skull fragments and back parts of the skull, this species was reassigned to Dysalotosaurus.

Finally we have the species D. canaliculatus, described in 1976, but later reassigned to the genus Valdosaurus.

Dryosaurus Classification

Dryosaurus is the representative that gives its name to the family Dryosauridae, a group of ornithopod dinosaurs that are iguanods.

Although the relationship between Dryosaurus and other Dryosaurids is not clear.

For a long time, the Dryosaurus was considered a representative of the family Hypsilophodontidae.

Until 1984, researchers Milner and Norman created the family Dryosauridae, in order to establish the differences between Dryosaurus and Hypsilophodontidae.

When did the Dryosaurus live?

This dinosaur lived to in the late Jurassic, about 150 and 147 million years ago, in the Titonian.

As for its habitat, the place where it was found (the Morrison Formation), was characterized by being semi-arid, with wet and dry seasons.

This area extended in what is now known as New Mexico in the United States, to Alberta in Canada.

What did the Dryosaurus eat?

According to the researcher John Foster, given the arrangement and characteristics of the teeth, it fed on low vegetation in the wide plains of the Morrison Formation.

Dryosaurus Characteristics

This dinosaur could measure between 3 and 5 meters long, besides they were about 2 meters high and weighed an average of 85 kilograms.

Dryosaurus showed a typical body structure of the Dryosaurs. The hind legs were long, the tibia being longer than the femur.

The arms were short and ended in five fingers.

The sacrum consisted of six fused sacral vertebrae, while the anterior and posterior parts of the pubic bone were long and thin.

The intermaxillary (premaxillary) bone, a bone sitting in front of the maxilla, was toothless, unlike the representatives of Hypsilophodontidae.

The jaws ended in a beak like that of the turtles.

This dinosaur was relatively small, besides it had no shell or horns to protect itself, so the Dryosaurus had only one way to survive the attack of a predator: escape.