1. Reptiles

2. Characteristics of a Reptile
Vertebrate animals
Lungs
Scaly skin
Amniotic egg
Characteristics of a Reptile
Vertebrate animals
Lungs
Scaly skin
Amniotic egg

3. Characteristics of Reptiles – Adaptations to life on land
More efficient lungs and a better circulatory system for life away from water
Scaly skin provides protection against the elements and desiccation
The amniotic egg protects against desiccation

4. Reptile Lungs- Another Adaptation to Life on Land
A more efficient respiratory system
Reptiles use two efficient lungs (except snakes – they only have one long functional lung that fits their bodies, the other is vestigial)

6. Excretion Kidneys produce urine in the form of uric acid
Uric acid crystallizes when concentrated, and is eliminated as a white paste (like birds)
Urine is either passed out directly through the cloaca, or stored in the urinary bladder where water is further reabsorbed

7. Scaly Skin An adaptation to life out of water Waterproof Dry, leathery
Protective scales
Must be molted

9. Watertight Skin
Reptile are covered by thick, dry, scaly skin that prevents water loss
Cells with a high keratin content
Lipids and proteins in the skin make it watertight conserving water and guarding against injury, infection and wear and tear

10. Amniotic Egg – Reptiles and Birds
Reptile eggs have a leathery shell
Has several membranes
Contains yolk rich in nutrients for embryo

11. Amniotic Egg Membranes
Amnion – thin membrane holds the fluid the embryo floats in
Yolk sac – holds the yolk (fatty food) for the developing embryo
Allantois – holds embryos nitrogenous wastes
Chorion – surrounds all the other membranes; protects embryo

12. The Amniotic Egg – adaptation to life on land
Amphibians are not able to move away from the water because their eggs would desiccate
Reptiles eggs prevent desiccation

13. Reptile Feeding Ex. 1: Iguana
Herbivores – tear plants using teeth and jaws
Have long digestive systems

14. Carnivores
Snakes – have extendible jaws to swallow their prey whole.

15. Carnivores Some snakes have a diet of eggs exclusively.
They swallow the egg whole, pierce the shell with a specialized section of the vertebrate, suck out the insides and regurgitates the shell

16. Carnivores
The king cobra eats other snakes

17. Breathing Tube

18. Carnivores
Monitor lizard – kills prey with sharp teeth and powerful jaws

19. Carnivores
Chameleons – have long sticky tongue that they flip out to catch flying insects .

20. Nervous Systems Frog Brain Alligator Brain
Larger cerebrum/ cerebellum than the amphibians
Daytime reptiles have good color vision: turtles can see color better than humans

21. Excellent Sense of Smell - Snakes
Have pair of nostrils
Also have special organs (vomeronasal organs) on roof of mouth
Tongue picks up chemicals and brings them to the vomeronasal organs to “taste” the air

22. Hearing
Most lizards have simple ears like an amphibian: external tympanum, single bone to transfer sound to inner ear . (we have an internal tympanum and 3 bones)
Snakes have no ears and are deaf – they “hear” the vibrations from the ground

23. Hearing - tortoises
Tortoises do not have a tympanum, but have a sound-conducting patch of skin on their head.
A “Red Ear Slider” turtle

24. Heat Sensors
Pit vipers are able to detect heat, to obtain a temperature image of their environment
Normal view Infrared view Combined view

25. Pit vipers

26. Snakes - movement Snakes press their ventral scales against the ground
Muscles around the ribs expand and contract in waves causing the s-shaped movement

27. Movement
A snake has a backbone of 100 to 400 vertebrae, each of which has a pair of ribs attached.
- Providing the framework for thousands of muscles
The interaction of bones, muscles, and skin enables asnake to move in one of three basic ways:
1. Lateral undulation
2. rectilinear movement
3. side winding.

28. Gecko – suction cup toes
Geckos have special flaps of skin on its toes – creating very sticky appendages

29. Reptile Reproduction Most have internal fertilization
Penis delivers sperm into cloaca of female

30. Reptile Reproduction Internal fertilization
Male inserts penis into female’s cloaca
Female’s body coats the embryos in protective shell, with membranes and yolk sac

31. Reptile Reproduction Most reptiles are oviparous
Some provide minimal care

33. Modern Reptiles
Reptiles are classified into 16 orders, 12 that are extinct.
- 4 surviving-6, 000 species
Reptiles occur worldwide except in coldest regions
- Human intervention-major impact
4 living orders of Class Reptilia:
- 1. Rhynchocephalia,
- 2. Chelonia,
- 3. Crocodilia,
- 4. Squamata

34. Rhynochocephalia Only living species- Sphenodon punctatus- the tuatara
-  Inhibit islands of coast of New Zealand
- Resembles a large lizard about 60 cm long
- Has an inconspicuous third eye on top of its head- parietal eye- functions as a thermostat- protects from overheating
- Active at low temperatures and feed at night on insects, worms and small animals

35. Chelonia Order consists of about 265 species of turtles and tortoises
- Tortoise are terrestrial Chelonia (Galapagos tortoises)
- Turtles- chelonians that live in water
- Body covered by a shell made of hard plates- 2 parts- a carapace and plastron
- Shape is modified for variety of ecological demands
- retract heads, swimming
- Forelimbs of a marine turtle have evolved into flippers and freshwater turtles have webbed toes
- Migratory behavior of sea and river turtles
-return to land to lay eggs

36. Crocodilia
Order composed of 20 species of large lizard-shaped reptiles- crocodiles, alligators, caimans and gavials 
- Descendants of archosaurs
Crocodilians live in or near water in tropical/ subtropical regions of the world
- Crocodiles- nocturnal animals; Africa, Asia and Americas
-  Alligators - China and southern U.S.
- Caimans- Central America- some in Florida
- Gavials- eat fish; long and slender snout- live only in Burma and India

37. Carnivorous- hunt by stealth- features adapted for this behavior
  - Eyes on head, nostrils on top of snout
-see and breathe while in water
- Valve to prevent water from entering air passage
- Parental care- both parents care for young by carrying in jaws until development

38. Squamata Order consists of 5,640 species of lizards and snakes
- Loosely jointed upper jaw and paired reproductive organs in males
- Structurally diverse
Lizards- presence of limbs
- Common lizards- iguanas, chameleons, skinks and geckos
 -  Live everywhere except Antarctic
- Special adaptations- agility and camouflage
- 2 species are venomous- Gila monster (SW U.S.) and beaded lizard (western Mexico)
- Most prey on insects or small animals

39. Blend with background
- chameleons- remain inconspicuous and fend off enemies
- Horned lizards- spiked armor, when disturbed they inflate themselves, gape, hiss and squirt blood from eyes
- Skinks and geckos- lose their tails and regenerate- autotomy- escape from predators
- Most lizards are small- .3m in length; iguanas- 1m in length
- Largest lizards- monitors- Komodo dragon (Indonesia) 3m
- Consume prey whole and use tail as defense weapon

41. Order Sphenodontida (Rhynchocephalia) - tuatara
2 spp. - max. length c.600mm.
most primitive living reptile, unchanged for 200my, relatives extinct 60 mya.
primitive features: pineal eye structure, foramen (openings) in skull, teeth fused to jawbone, no ear opening.
temperature-dependent sex determination in incubating eggs.
caudal autotomy - lose tail voluntarily; fracture planes within vertebra; tail regrowth.
formerly widespread, now restricted to c.30 offshore islands.

42. NZ reptile fauna
Sphenadon punctatus

43. Order Squamata - lizards & snakes Lizards:
at least 80 lizards species and subspecies of lizard known in New Zealand (still being discovered and described).
caudal autotomy.
lizards represented by geckos and skinks in New Zealand
Robb 1980

44. Robb 1980

45. Geckos
flattened body with short legs
granular scales, transparent scale over eye
eyelid non-moveable, cleaned by the tongue
able to climb vertical surfaces - specially adapted gripping bristles (lamellae) underneath toes
can make noises - chattering sound when disturbed or threatened
most southern geckos in the world, largest species (kawekaweau, extinct)
NZ species retain eggs in body to give birth to live young (ovoviviparity

47. 2 NZ genera
Hoplodactylus – 9 spp. (1 extinct), brown, limited colour change, nocturnal
- Naultinus – 7 spp., green, diurnal

48. Skinks
elongated body, rounded in cross-section, long tapering tail.
very agile.
flat, shiny, overlapping scales.
moveable eyelids (blink).
most ovoviviparous.

49. 2 NZ genera
- Cyclodina – 6 spp. (1 extinct), diurnal.
- Oligosoma (Leiolopisma) – 21 spp. (1 extinct), nocturnal or crepuscular.
- [1 introduced sp. – rainbow skink, northern Nth Is.]

50. Other reptiles?
- turtles
- snakes
- crocodiles

51. Evolution of Reptiles
TRANSITION FOSSILS show that there was a slow and steady evolution from amphibians to reptiles.

53. Age of the Large Reptiles
Approximately 195 million years ago, the mammal-like reptiles that populated the world disappeared and were replaced by the dinosaurs

54. Mass Extinction – 65mya
Scientists not sure why the dinosaurs disappeared
Possibly the world was hit by a meteor
Only relatively small reptiles were left behind

55. Major radiation into all ways of life; terrestrial, aquatic, aerial.

56. Ichthyosaurs: fully aquatic, but air breathing
Ichthyosaurs: fully aquatic, but air breathing. A reptile equivalent to whales or porpoises. Mostly fish eating.

60. Pterosaurs = hang glider wings.

62. Archosaurs = major dinosaur groups
Plus crocodiles, and bird ancestry.

63. A very diverse and complex group
A very diverse and complex group. - die out at Cretaceous boundary = meteor?