W2 L4b - Order Testudinata (Turtles)

Question 1

When were the earliest fossils of Testudines (Turtles) found?

Answer 1

Late Triassic

Question 2

What is the only retained feature Testudines (Turtles) have?

Answer 2

Anapsid Skull

Question 3

What features are derived in Testudines (Turtles)?

Answer 3

• Encased in bone
• Limbs inside ribs
• No teeth; horny plate/beak and pressure
• Egg laying, direct development (oviparous)

Question 4

Where do Testudines (Turtles) live and how many species are there?

Answer 4

• Terrestrial, Freshwater/Semi-Aquatic, and Marine
• 300 species globally

Question 5

What evolution aided Testudines (Turtles) against predators?

Answer 5

Turtle Shells:
- Epidermal Scutes, sharp ends of pectoral bone
- Dermal bones, as the shell
- Fused vertebrae with Dermal bones
- External ribs, as limbs

Question 6

How does the turtle shell grow?

Answer 6

From 59 separate centers of ossification

Question 7

How do Turtles breathe in a hard shell?

Answer 7

• Large lung
• Tethered, Complex array of muscles
• Contract/relax those muscles to fill/empty lungs; negative pressure breathing

Question 8

How do Turtles breathe through a soft bottom?

Answer 8

Cloacal Respiration:
- Accessory respiration; large cloacal cavities lined with many finger-like papillae
- Papillae has a rich blood supply; increases surface area
- Turtles take up dissolved oxygen from the water using Papillae; similar to gills in fish

Question 9

Describe Turtles thermoregulation and circulation

Answer 9

• Ectothermic
• Behavioral thermoregulation
• Easy for small turtles; high SA volume
• Difficult for large Terrestrial turtles (thermal inertia)
• Counter-current circulation; conserves heat

Question 10

What are a Turtles diet?

Answer 10

Foragers, highly diverse diet:

 - invertebrates, jellyfish, sponges, crustaceans, plants

Question 11

How do Turtles eat?

Answer 11

Procuring; snapping or suction feeding

Processing; beak or lips

Question 12

Turtle Locomotion

Answer 12

Tortoises ➡ fully terrestrial

Turtles ➡ semi-terrestrial to fully aquatic/marine

Question 13

Turtle Reproduction

Answer 13

• Oviparous (soft or rigid eggs)
• Internal fertilization
• Female lays eggs in sand/soil
  
  • Synchronized hatching
  • Long distance migrations; some travel 16,000 km during a breeding season

Question 14

What conditions influence Egg development in Turtles?

Answer 14

• Soil temperature (middle trimester)
  ➡ determines hatchling sex (TSD)
• Soil moisture
  ➡ hatchling size

Question 15

What are two suborders in the Testudine order?

Answer 15

Cryptodires and Pleurodires

Question 16

Cryptodires Info

Answer 16

• > 10 Families
• Highly diverse; mostly Northern Hemisphere
• Paddle-like front limbs
• Pelvic girdle bone connected to shell
  
  • i.e. shorter necks
• Trochlear process ➡ anterior otic capsule

Question 17

Pleurodires Info

Answer 17

• 2 Families
• Southern Hemisphere
• S-shape retractable head/neck
• Pelvic girdle fused to carapace and plastron
  
  • i.e. longer necks
• Trochlear process ➡ lateral pterygoid

Question 18

Wh