Theropoda
The word ‘Theropod’ comes from the Greek for ‘beast feet’. Theropods were bipedal (walked on two legs),
primarily carnivorous saurischian dinosaurs who appeared in the Late Triassic Period. In the Jurassic, birds
evolved from theropods. The theropods included the largest land-living carnivores ever to have walked the
Earth (such as the Tyrannosaurus Rex).
Several main characteristics typify a theropod zz hollow, thin walled bones
zz clawed hands (usually with three main digits)
There is much debate about how the theropods are
classified, and the way that palaeontologists classify
them is in a state of constant flux, however we are
going to look at two main groups of Theropod, the
Ceratosauria and the Tetanurae.
zz carnivorous (predominantly)
zz well developed jaw muscles, often with sharp teeth
for eating flesh
Ceratosaurus
Tetanurae
The Tetanurae were a large, diverse group of therapods which had a few features that most Tetanuran members
possessed (those that did not have these features had lost them during their evolutionary history). They had an
enlarged hand (manus) and a loss of the fourth and fifth digits on these hands. They also had a less flexible tail. The
Tetanurae range from tiny to huge and there are two main types, the Carnosauria and the Coelurosauria:
On average, the Carnosauria were
larger than most therapods, with a
name meaning ‘meat-eating lizards’
in Greek. They peaked during the
Jurassic Period . They had several
characterizing features, mostly
related to the pelvis and hind
legs. Their femur (thigh bone) was
usually larger than their tibia (shin
bone), they had large orbits (eye
openings in the skull) and a long,
narrow skull. Many of them had
good-sized forelimbs, unlike the
Tyrannosauridae, where we see the
short armed Tyrannosaurus Rex we
are all familiar with! An example
Carnosaur is the Allosaurus.
Allosaurus
T H