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Order Caudata (Salamanders)

Order Caudata (Salamanders). Fred Searcy ZOO2010. Order Caudata (L caudatus = tail). Salamanders & Newts 360 species worldwide Temperate, tropical, subtropical Endangered. Structure. Usually < 15cm Japanese giant salamander 1.5 m

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Order Caudata (Salamanders)

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  1. Order Caudata(Salamanders) Fred Searcy ZOO2010

  2. Order Caudata(L caudatus = tail) • Salamanders & Newts • 360 species worldwide • Temperate, tropical, subtropical • Endangered

  3. Structure • Usually < 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

  4. 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

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

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

  7. 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.

  8. Urogenital System • Paired kidneys on either side of dorsal aorta • Bowman’s capsules present • Urinary bladder • Ammonia converted to urea • Some species convert urea to uric acid

  9. 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)

  10. 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

  11. Thermoregulation and Metabolism • Poikilothermic (ectothermic) • Behavioral regulation

  12. 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 Breeding Behavior & Reproduction

  13. Metamophrosis & Paedomorphosis • Some are aquatic throughout life and don’t undergo metamorphosis – they retain their gills as adults • Paedomorphism – adult retains some larval traits, e.g. gills • Necturus sexually mature in larval stage

  14. 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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