Dinosaurs A to Z
Plateosauridae

Plateosaurus trossingensis PLAT-ee-oh-SOR-us

"Broad lizard"

Plateosaurus silhouette
You 1.8 m (5.9 ft) tall
Plateosaurus 8 m (26.2 ft) long
as long as 5 people standing fingertip to fingertip
silhouette · Olof Moleman (CC-BY) via PhyloPic
Length
8 m (26.2 ft) — About 8 m long, ~4 tonnes — one of the first large dinosaurs.
Period
Late Triassic (214–204 Mya)
Place
Europe · Germany · Switzerland · France
Food
Herbivore — Soft plants — Plateosaurus probably reared up to reach high foliage.
Clade
Plateosauridae Dinosauria Saurischia Sauropodomorpha Triassic-Jurassic prosauropods, ancestors to giant sauropods.

A Late Triassic plant-eater so common in German quarries it earned the nickname "Swabian lindworm".

Plateosaurus reconstruction by Leandra Walters, Phil Senter, James H. Robins
Reconstruction · Leandra Walters, Phil Senter, James H. Robins (CC-BY)

Plateosaurus is one of the oldest large dinosaurs known, living more than 200 million years ago when most reptiles were still small. It walked on two legs but could rear up on the back legs to reach high branches, with leaf-shaped teeth for cropping plants. Whole bonebeds in Germany preserve dozens of individuals, possibly killed when they got bogged down in mud.

More about Plateosaurus

Discovery

Named by Hermann von Meyer (who named it; bones first found by Johann Friedrich Engelhardt) · 1837 · Heroldsberg near Nuremberg, Germany

In 1834 the physician Johann Friedrich Engelhardt dug up some vertebrae and leg bones at Heroldsberg near Nuremberg. Three years later the German palaeontologist Hermann von Meyer made them the type specimen of a new genus, Plateosaurus.

The name probably means "broad lizard", from the Ancient Greek platys ("broad"). It is often translated as "flat lizard", but that meaning came from a later, secondary reading of the same Greek word and from a competing derivation proposed by Agassiz; von Meyer's original 1837 description gave no etymology at all.

Portrait of Hermann von Meyer
Hermann von Meyer A German palaeontologist who described and named Plateosaurus in 1837, making it the fifth still-valid named dinosaur genus.
Why did fully grown Plateosaurus come in such different sizes?
Unusually for a dinosaur, it showed strong developmental plasticity. Instead of converging on a fairly uniform adult size, fully grown individuals varied in length and weight. Most lived at least 12 to 20 years, but the maximum life span is not known.
For the curious → How settled is the species list?
The text lists three valid species: P. trossingensis, P. longiceps, and P. gracilis. Many other names have been assigned in the past and there are numerous genus-level synonyms, and there is no broad consensus on the species taxonomy of plateosaurid dinosaurs.

What we know

  • Lived more than 200 million years ago, in the Late Triassic.
  • Walked on two legs and reared up to reach high foliage.
  • Hundreds of skeletons known from German bonebeds — likely a mud trap.
  • Direct ancestor of the giant sauropods that came later.

What we guess

  • Whether it migrated seasonally or stayed in one area.
  • Exact diet — soft plants and possibly some small animals or insects.
  • Whether the bonebed represents one event or accumulated over years.