Amniote Review
1. Did the Amniotes come from Anurans (Frogs/Toads) , Urodels (Salamanders), or Gymophonians (Caecilians), or none of the above?
2. Identify the Amnoites in the phylogeny below.
3. Identify the Sauropsids in the phylogeny below.
4. Identify the Testudines in the phylogeny below.
5. Identify the Lepidosaurs in the phylogeny below.
6. Identify the Archosaurs in the phylogeny below.
Amniotic Egg
Boil an egg and let it cool. Examine the egg structures described below
Structure of Ovum
Shell
Examine the shell
1. shell membranes added as egg travels through oviduct
2. fertilization must occur prior to egg formation
3. Mechanical support
– leathery and flexible (lizards)
– calcified and rigid (birds)
4. Gas/water Exchange
– Most egg shells porous, allow exchange with environment
– Birds have Cleidoic egg (closed egg)
Does the Cleidoic bird egg allow high or low levels of gas exchange through the shell?
Yolk sac
Find the Yolk
1. added prior to ovulation
2. Yolk contains many layers
What is the function of the Yolk?
Albumin
Examine the egg white
1. added in oviduct
2. many layers, differ in viscosity What is the likely function of the egg white?
Turtle Shell
1. Examine the Plastron Exterior
– Learn the Types of Epidermal Scutes on the plaston
2. Examine the Plastron interior
– Notice the pattern of dermal bone
– Does the dermal bone pattern match that of the epidermal scutes?
Why or why not?
3. Examine the Exterior of the Carapace
– Learn the Types of Epidermal Scutes on the carapace
4. Examine the Plastron interior
– Notice the pattern of dermal bone
– notice the ribs of the
– can you reconstruct the interior skeletal elements?
Turtle Diversity
Order Testudines
Two major clades of extant turtles based on neck retraction
12-13 families of turtles
Turtle Diversity
Order Testudines
Suborder Cryptodira
– retract neck by bending neck bones vertically – 4 major groups
1. Chelydridae – snapping turtles
2. Platysternidae – asian snappers
Order Testudines
Suborder Cryptodira
Superfamily Cheloniodea – sea turtles
Family Cheloniidae – Sea Turtles
Green Turtle
Loggerhead
Pacific Ridley
Hawksbill
Family Dermochelyidae – Leatherback sea turtles
Characteristics
Totally marine – Except when laying eggs
Limbs modified into paddles
Large size
Cheloniidae – 70cm to 1.5 M length
Dermochelyidae – 1M to 2.4M length
Order Testudines
Suborder Cryptodira
Superfamily Trionychoidea
Family Trionychidae – soft-shelled turtles
Family Kinosternidae – mud and musk turtles
Family Carettochelyidae – softshelled sea turtles
Family Dermatemydidae – Phyrangeal breathers
Order Testudines
Suborder Cryptodira
Superfamily Testudinoidea
Family Testudinidae – Tortises
Family Emydidae – box turtles and water turtles
Largest Family – 80 species
Western pond turtle
Painted turtle
Slider Western Box Turtle
Order Testudines
Suborder Pleurodira
– retract neck by bending neck bones horizontally
– bring head close to side of body in gap between shell
– only Aquatic – freshwater turtles
– 15-19 cm in length – Broad flat shells
