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1. Reptiles
Early Classification

2. Groups of early reptiles
 There are three main reptile groups, all differentiated
by the number of openings in the skull (besides those
for the eyes and nasal passages).These openings are
called vacutaes.
 The three reptils groups are:
 Anapsids - No additional openings
 Synapsids - One additional opening
 Diapsids - Two additional openings

3. Groups of early reptiles
 Anapsids
 The anapsids skulls have no openings.
 Most of the anapsids did not survive the
Permian Extinction, those who did survive
produced the first turtles which appeared in the
Triassic.
 Our modern turtles are descended from these
primitive Triassic turtles.

4. Groups of early reptiles
 Synapsids
 Synapsids appeared in the Carboniferous along with
the other reptile groups.
 Some well-known Permian synapsids included the
dimetrodon with its magnificent sailfin on its back.
 Dimetrodons (see image) belonged to the larger group
called pelycosaurs who proved to be very successful
during the late Carboniferous and early Permian.

5. Groups of early reptiles
 Subgroup of Synapsida- Therapsids
 Therapsids (mammal-like reptiles and
mammals) arose in the Permian as part of the
synapsid line, but only a few groups survived
the Permian Extinction.
 The therapsids consisted of three main groups:
Anomodonts - These were mostly
herbivores and first appeared in the Middle
Permian.
Theriodonts - These were the most
mammal-like of the therapsids and appeared
at the same time as the anomodonts (Middle
Permian). It is from the theriodont line
that all mammals developed.
Dinocephalians - These early therapsids
lived only during the Middle Permian.

6. Groups of early reptiles
 Diapsids
 Diapsids have two holes, both located behind
the eye socket.
 Members of the diapsids included some of the
more famous Mesozoic creatures:
 Archosaurs
 Dinosaurs
 Pterosaurs
 Archaeopteryx
 Marine reptiles such as Plesiosaurs and Mososaurs
 Today modern diapsids include birds, crocodiles,
lizards, snakes and all other reptiles.

7. Dinosaurs
 Triceratops
 Triceratops was the most numerous of the
horned cretaceous dinosaurs as well as the
largest ceratopsian;
 it was one of the last to become extinct.
 Its name means "three horned face".
 Triceratops was a herbivore and its largest
predator was Tyrannosaurus rex.

8. Dinosaurs
 Tyrannosaurus
Tyrannosaurus rex was a fierce predator
that walked on two powerful legs.
T. rex was a huge meat-eating dinosaur
that lived during the late Cretaceous
period, about 85 million to 65 million
years ago.

9. Dinosaurs
 Stegosaurus
Stegosaurus was a large herbivore from
the Jurassic Period.
It had a plated back and a spiked tail.
 Stegosaurus measured up to 26-30
feet long (8-9 m)

10. Brachiosaurs
 Brachiosaurus was one of the tallest and
largest dinosaurs yet found.
 It had a long neck, small head, and
relatively short, thick tail.
 Brachiosaurus walked on four legs and,
like the other Brachiosaurids and
 unlike most dinosaurs, its front legs were
longer than its hind legs.
 These unusual front legs together with its
very long neck gave Brachiosaurus a
giraffe-like stance and great height, up to
40-50 feet (12-16 m) tall.

11. Pteranodons
 Pteranodons were flying, prehistoric
pterosaurs, reptiles related to the
dinosaurs.
 Pteranodons lived during the late
Mesozoic, going extinct in the cretaceous
extinction.