7. Groups of Reptiles
Sauria (lizards)
Serpentes (snakes)
Testudines (turtles)
Crocodylia (crocodiles)
Rhynchocephalia (tuataras)
8. Reptile Characteristics
• Ectothermic
• Dry skin covered in scales
• Most have 2 pairs of short legs & clawed feet
• Oviparous reproduction (Internal fertilization – to
avoid desiccation of gametes)
• Eggs have a leathery shell and yolk (amniotic)
• Lungs to breathe
• 3 or 4 chambered heart
• No metamorphosis (young look like miniature parent)
• Hibernate & aestivate
14. • Turtles add new
layers of
keratin under
old layers of the
plate-like scutes
(modified
scales)
15. Reptile Legs
• Short tetrapods for
walking
• Positioning of the
legs more directly
under the animal.
This position
provided more
support than the
splayed arrangement
of the Amphibian
legs.
16. Paired Limbs
• The paired limbs usually have five toes and are
variously adapted for:
• Swimming
• Running
• Climbing
• (Absent altogether in the snakes)
17. Reptile Lungs
• Respiration is no longer through the skin, but
only through internally protected and
moistened lungs.
24. Squamata
• “Characterized by
scales”
• Lizards, snakes
• Most recent products
of reptile evolution
• Most successful - 95%
of known living species
of reptiles
25. Squamata
• Lizards began
diversifying at time
when dinosaurs were
near end of their
dominance
• Were successful because
of adaptability
• Adopt various body
forms, occupy various
habitats
26. Lizards
• Very diversified group
• Terrestrial, burrowing,
aquatic, arboreal,
aerial
• Many familiar groups
27. Lizards
• Geckos
• Mostly small,
nocturnal, with
adhesive toe pads
(walk anywhere)
• Iguanas
• Often bright-colored
New World lizards
41. Crocodilia
• Unchanged for 160
million years
• Crocodiles larger, more
dangerous than
alligators
• Prey drowned, ripped
into pieces by rapid
rolling
• No natural enemies
42. Crocodilia
• Oviparous - lay eggs in
mass of vegetation
• Guarded by mother
• Incubation temperature
determines sex of
alligator hatchlings
• Low - females
• High - males
• 5:1 (M:F) in some areas
