Amphibian Adaptations

Amphibian Adaptations

  • Aposematic coloration = poison

  • toe pads and long limbs = arboreal. Toe pads use wet adhesion

  • Moist permeable skin = synapomorphy

  • Ancestral non-amniote tetrapods had scutes, bony scales

  • Synapomorphy = a characteristic present in an ancestral species and shared exclusively (in more or less modified form) by its evolutionary descendants.


  • Countershading for cryptic coloration

  • Most adult amphibians are carnivorous – eat anything they can catch and swallow

  • Mouths of many species are as wide as their entire head

  • Frog tongue attached at front of mouth

  • Frogs have vomerine teeth and maxillary teeth

  • Salamanders have small teeth on both jaws



  • Head size determines prey size

  • E. Narrowmouth Toad eats ants

  • Green Treefrog eats crickets, earthworms, moths

  • eats ants


  • eats crickets, earthworms, moths


  • Paedomorphy = retention of juvenile characteristics

  • Lateral line, absence of eyelids, external gills

  • Partial metamorphosis in Hellbender

  • Gills and lasagna sides increase surface area for gas exchange

  • Other end of spectrum – Plethodontidae young hatch from eggs with all adult characteristics



  • Nasolabial groove – chemoreception, lungless salamanders

  • Some species have cirri for chemoreception - this is how they find prey and how they find mates




  • Spermatophores – mucus with sperm. 

  • Most salamanders, not hellbenders. 

  • Males deposit in water, and females pick up spermatophore with cloaca. 

  • Fertilization is internal - ensures fertilization of eggs

  • Contains nutrition for female. 

  • Males deposit spermatophores on top of others


  • Explosive breeding – bufonidae, triggered by rain event, all come out at once, breeding balls

  • Prolonged breeding – others, longer season

  • Amplexus – male frog embraces female and deposits sperm as she lays external eggs



  • Top – Southern Leopard Frog egg masses

  • Bottom – spotted salamander egg masses

  • Laid in vernal pools without predators

  • Vocal sac - outpocket of the mouth cavity

  • Advertisement call for breeding, can be other types of calls

  • Some species don’t have vocal sacs; might do semaphoring behavior instead