Reptilia

Reptilia

1. Reptilia
Damnjanović Ivana

4. Gambassa

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

10. Ectothermy
–Body temperature
regulated by
ambient air
temperature

11. Dry Scaly Skin
The body of reptiles is
covered with horny
epidermal scales to
reduce water loss and
provide protection.

13. Shedding
•Snakes turn old
skin (scales,
epidermis) inside
out when
shedding

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.

18. Reptile Hearts
•Reptiles have a 3-chambered heart
•Crocodiles have a 4-chambered heart

19. Nervous System
•Sense organs generally well-developed
•Hearing generally poorly developed in most

20. Excretory Waste
•The excretory waste of the reptiles is uric
acid unlike the dilute, water wasting
ammonia in the urine of Amphibians.

21. Oviparous
•Eggs have a leathery
shell to prevent
desiccation

22. Amniotic Egg

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

28. Lizards
•Skinks
•Elongate bodies

30. Lizards
•Chameleons
•Tongue flicked to
greater distance than
body length

31. Draco volans

32. Snakes
•10 cm long up to 10 m
long
•Highly specialized
body form

33. Snakes
•Rearranged internal
anatomy
•Left lung reduced or
absent
•Hearing - no obvious
external ear
•Sensitive to vibrations
carried in ground

34. Snake Sense Organs
•Olfaction important,
but not in nostrils
•Jacobson’s organs
(vomeronasal organs)
•Tongue carries scent
particles to organ

35. Snake Feeding
•Skull, jaws highly
specialized for feeding
•Eat prey several times
their own diameter
•Non-joined mandibles
•Loose skull bones

36. Snake Feeding
•Venom - toxic
concentrations in
saliva
•Neurotoxic - blindness,
paralysis
•Hemolytic - ruptures
blood vessels, cells

39. Snake Feeding
•King cobra most
dangerous, largest (5.5 m)
- kill 9,000 people per
year

40. Snake Locomotion

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

46. Chelonia
•Turtles
•Very ancient group
•Little change in
morphology since
Triassic period

47. Turtle Shell Anatomy

49. Turtle Life Cycle

53. Sphenodonta
•Tuatara - single species
in New Zealand
•Lizard-like, <66 cm
•Lives in burrows
•Slow-growing, long-
lived (77 years)