Amphibians 2

Question 1

What are the general characteristics of gymnophionans (caecilians)?

Answer 1

• Annulated bodies
• Eyes have regressed in many species
• Chemosensory
• Dermal scales often present
• Operculum absent (no ear openings)
• Teeth are curved and relatively long in comparison to other amphibians.

Question 2

Describe reproduction in gymnophionans (caecilians).

Answer 2

• Internal fertilisation - male has intromittent organ

* Offspring may develop externally (oviparous) or internally (viviparous).

Question 3

Describe reproduction in urodeles (salamanders).

Answer 3

Male spermatophore and internal fertilisation. Males deposits one or more in front of female, female moves forward, aligns her vent above spermatophore and removes portion or all of sperm mass from top.

Question 4

Describe reproduction in Anura (frogs and toads).

Answer 4

• Vocalisation to attract females

* Amplexus: male fertilises eggs that are released by female (external fertilisation).

Question 5

What are the major reasons explaining the decline of amphibians?

Answer 5

• Habitat loss
• Habitat fragmentation
• Harvesting
• Pollution
• Pathogens e.g. Chytrid fungus skin disease.

Question 6

What are aquatic caecilians called?

Answer 6

Typhlonectidae.

Question 7

What are Caeciliidae?

Answer 7

Largest group of caecilians.

Question 8

What are Plethodontidae?

Answer 8

Largest family of salamanders.

Question 9

What are the general characteristics of urodeles?

Answer 9

• Trunk specifically segmented
• Presence of tail (humans & animals)
• 4 equal sized limbs that extend at right angle from body.

Question 10

What are the main features of Anura?

Answer 10

• Fibula and tabia are fused - hind limbs and muscle forms a level system that catapults them forward
• Posterior vertebrae are fused to form urostyle.

Question 11

Define paedmorphosis.

Answer 11

• Seen in salamanders

* Larvae become sexually mature without attaining full adult body form e.g. Mexican axolotl.

Question 12

Describe urodeles embryo development.

Answer 12

• Give birth to two young usually
• Only one embryo fully develops in each uterus
• Embryos nourished on other eggs which dissolve.

Question 13

Give the common methods of egg development in Anura.

Answer 13

• Directly in water
• Vegetation over water
• Foam nest
• Bromeliad nest.

Question 14

Give the common methods of parental care seen in Anura.

Answer 14

• Carry eggs on back of thighs
• Internal brooding
• Viviparous
• Carry eggs/tadpoles under skin.