Order Caudata (Salamanders)

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Order Caudata(Salamanders)

• Fred Searcy
• ZOO2010

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Order Caudata(L caudatus tail)

• Salamanders Newts
• 360 species worldwide
• Temperate, tropical, subtropical
• Endangered

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Structure

• Usually lt 15cm
• Japanese giant salamander 1.5 m
• Burrowing and aquatic forms may have rudimentary
  limbs or they may be missing
• Terrestrial forms have limbs at right angles to
  the body

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Nutrition

• Carnivorous as larvae and adults
• Protein rich
• Fat glycogen stored in small amounts
• Most are opportunistic feeders but some actively
  search for prey
• Teeth on upper and lower palate of mouth
• Slow metabolism less frequent eating required

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Digestion

• Large stomach proportional to body
• Cardiac and pyloric sphincter
• Pancreas
• Liver
• Gall bladder

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Cardiovascular

• Blood contains
• Erythrocytes
• Leucocytes
• Thrombocytes
• Circulatory System
• Vessels
• 3-chambered heart
• Lymph
• Lymph vessels

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Respiration

• Varied methods
• Integument
• External gills
• Lungs
• Both gills and lungs
• Neither gills nor lungs (pull air across buccal
  vascular membranes of mouth)
• Most have gills in larval stage
• Some aquatic forms have no gills and must surface
  for air.

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Urogenital System

• Paired kidneys on either side of dorsal aorta
• Bowmans capsules present
• Urinary bladder
• Ammonia converted to urea
• Some species convert urea to uric acid

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Auditory Vocal Functions

• No ear drums, no middle ear cavity
• Inner ear modified for sound perception
• Lateral lines in larval and aquatic species
  (water current and pressure changes)

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Skin, Pigmentation, Glands

• Serous glands may be toxic or noxious some
  lethal
• Concentrated behind head or in parotid gland
  (warts) on skin
• Mucous glands
• Keep skin moist
• Prevent infections
• Lubricate path through water
• Chromatophores
• Melanocytes
• Cryptic coloration
• Aposematic coloration (warning)
• Iridophores
• Xanthophores
• Erythrophores

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Thermoregulation and Metabolism

• Poikilothermic (ectothermic)
• Behavioral regulation

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Breeding Behavior Reproduction

• Aquatic species secrete pheromone
• Some terrestrial species rub chins
• Internal fertilization with spermatophore typical
  but some external fertilziation
• Eggs layed in strings with gelatinous layer
• Larva with gills tails
• Oviparous, viviparous, ovoviviparous

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Metamophrosis Paedomorphosis

• Some are aquatic throughout life and dont
  undergo metamorphosis they retain their gills
  as adults
• Paedomorphism adult retains some larval traits,
  e.g. gills
• Necturus sexually mature in larval stage

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Metamophrosis Paedomorphosis

• Ambystoma
• Only change to adult under specific environmental
  conditions
• E.g. pond dries up, change to adult
• Larval form called axolotl
• Can force metamorphosis by treating axolotl with
  thyroxine from thyroid gland

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