REPTILIA

Characteristics

Body covered with keratinized epidermal scales Integument with few glands

Two paired limbs, usually with five toes Adapted for various functions

(climbing, running, paddling, etc) Skeleton well ossified

Skull with one occipital condyle a protrusion on the skull that forms a joint that

enables movement of the head; allows a wider range of motion

Characteristics

Respiration by lungs Pharynx or skin used by some

Ectotherms 12 pairs of cranial nerves Internal fertilization Eggs coved with calcareous or leathery

shells

Characteristics that distinguish them from amphibians

Tough, dry, scaly skin Protection against drying out & physical

injury Chromatophers

Color-bearing cells Amniotic egg permits rapid

development Jaws designed for applying crushing or

gripping force to prey Some form of copulatory organ

permitting internal fertilization

Characteristics that distinguish them from amphibians

Efficient & flexible circulatory system & higher blood pressure

Lungs are better developed Suck air into lungs (amphibians force air into

lungs) Developed efficient strategies for water

conservation Better body support

Limbs designed for life on land Nervous system more complex

Living Reptilian Groups

Order Testudines turtles

Order Squamata Snakes, lizards, worm lizards

Order Sphenodonta Tuataras

Order Crocodilia Crocodiles & Alligators

Turtles: Order Testudines

Enclosed in shells Shell is fused to thoracic vertebrae & ribs Protection for the head & appendages

Jaws are provided with tough, keratinized plates (lack teeth)

Poor sound perception & most are mute Good sense of smell & color vision Oviparous & internal fertilization

Turtles: Order Testudines

Nest temperature determines sex of hatchlings Low temperatures produce males High temperatures produce females

Marine turtles can reach great size Leatherbacks – 2 m (6 feet) & weight up to

900 kg (2,000 lbs) Most are slow moving & low metabolism

A female leatherback sea turtle heaves herself from the surf at night to nest. Females often return to the same nesting areas where they were born to produce their own offspring.

Lizards, Snakes, & Worm Lizard: Order Squamata

~95% of all known living reptiles

Kinetic skull Movable joints Enables seizing &

manipulating prey

Lizards, Snakes, & Worm Lizard: Order Squamata

Lizards Terrestrial, burrowing, aquatic, arboreal, &

aerial members Includes Geckos, iguanas, skinks, and

chameleons Most have movable eyelids

Keen vision for daylight Ectothermic

Gila Monster

Lizards, Snakes, & Worm Lizard: Order Squamata

Snakes limbless & usually lack both pectoral &

pelvic girdles Numerous vertebrae – shorter & wider than

most tetrapods Highly kinetic skull

Allows snakes to swallow prey several times their own diameter

No movable eyelids & no external ears Sensitive to vibrations through the ground

Lizards, Snakes, & Worm Lizard: Order Squamata

Snakes Jacobson’s organs

Pitlike organs in the roof of the mouth – lined with olfactory epithelium; richly innervated

Forked tongue Flicked through the air, picks up scent

molecules Capture prey with mouth & swallow it while

it is still alive Some kill prey first by constriction Some inject with venom (less than 20% of

snakes are venomous)

Lizards, Snakes, & Worm Lizard: Order Squamata

Snakes Family Viperidae

Pit vipers – posses heat-sensitive pit organs between nostrils & eyes

Use pits to track warm-blooded prey & to aim strikes N. American venomous snakes are pit vipers

Rattlesnake, water moccasin, copperheads Teeth modified as fangs

Venom injected through a canal in the fangs Neurotoxic venom

Acts on nervous system; affecting the optic nerves (blindness) or phrenic nerve of diaphragm (paralysis of respiration)

Hemorrhagin venom Destroys red blood cells & blood vessels

Lizards, Snakes, & Worm Lizard: Order Squamata

Snakes Most are Oviparous

Producing eggs, with a shell, that hatch outside the body.

Some are Ovoviviporous (American pit vipers) carry the eggs internally and upon delivery of the

offspring the entire shell structure has thinned to the point that only the thin mucous membrane remains from which the offspring emerges.

Few are Viviparous True live-bearing

Tuataras: Order Sphenodonta

Sphenos – wedge; odontos – tooth Lizard-like form (66 cm long) Slow-growing with long life

Recorded to have lived 77 years Found only in New Zealand

Crocodiles & Alligators: Order Crocodilia

Crocodilians Elongate, robust, well-reinforced skull &

massive jaw musculature Provides a wide gape & rapid, powerful closure

Complete secondary palate Allows breathing when mouth is filled

Oviparous Lays 20-50 eggs

Can weigh up to 1000 kg (~2200 lbs)

Alligators Less aggressive Alligators have

wider, U-shaped snouts is more pointed and V-shaped

Crocodiles & Alligators: Order Crocodilia

Continental Reptiles Research

Research the REPTILES of assigned continent 1. North America

2. South America3. Europe4. Asia5. Africa6. Australia (Oceania)

For each reptile include the following Order Appearance (drawing) Size Diet Habitat Range Status (common, rare, threatened, or endangered)