Class Reptilia

Subclass Anapsida

Order Testudines - turtles

Subclass Diapsida

Superorder Lepidosauria - all modern reptiles; except turtles and crocs

Order Squamata - lizards and snakes

Order Sphenodonta - tuatara

Superorder Archosauria - dinosaurs, crocs, and birds

Order Crocodilia - crocs and alligators

Order Saurischia - descendants of living birds - from the theropods.

Subclass Synapsida - mammal-like reptiles

Order Therapsida - descendants of living mammals

Amniotes:

1. Anapsids -

2. Diapsids -

3. Synapsids -

Characteristics of Reptilia

1. Tough, dry, scaly skin.

scales epidermal (those of fish are dermal)

2. Shelled (amniotic) egg

3. Jaws

4. Copulatory organs

5. More efficient circulatory system

atria completely separated from each other; partial ventricular separation - except crocs (two atria and two ventricles)

6. Lungs better developed

7. Evolved efficient strategies for water conservation

metanephrous kidney; salt glands

8. Better body support; efficient limb design

9. Nervous system more complex

Cerebrum size increased

Anapsid Reptiles:

- shell:

fused to vertebral column and ribs

dermal bone with outer layer of epidermal scutes

- lack teeth

- use limbs and muscles to draw air into lungs

- all oviparous; all laid in gastrula stage of development

TSD or GSD

Can store sperm and have multiple paternity

Males use concavity of plastron to mount female turtle

- Long lived

Diapsid Reptiles:

Order Squamata -

- kinetic skull

Lizards

- 4 limbs but some limbless

- moveable eyelids and external ear

Amphisbaenids

- No limbs; burrowing animals

- no visible eyes or ears

- One species in Florida; most in South America and Africa

Snakes

- No limbs or girdles (except pythons and boas)

- Numerous vertebrae and ribs

- Kinetic skull

- Transparent membrane over eye = spectacle

- No external ear

- Jacobson's organ = vomeronasal organ

- Movement

- Poisonous snakes = rattlesnakes, water moccasins and copperheads (pit vipers);

- Venom used for subduing prey (kill) and digestion

- Oviparous, ovoviparous, and some viviparous

Order Spenodonta - tuatara

- Two living species - islands off New Zealand

- Lives in burrows

- Long lived

- Parietal eye

Order Crocodilia - crocodiles and alligators

- teeth set in sockets (thecodont)

- complete secondary palate

- oviparous - parental care of young

- all have TSD. Cool females and hot males