Kingdom - Animalia

Phylum - Chordata

Class - Amphibia

Order - Anura

Families in Illinois:

  • Hylidae,
  • Ranidae,
  • Bufonidae,
  • Pelobatidae,
  • Microhylidae
  • Fowler's Toad

  • American Toad

  • Cricket Frog

  • Green Treefrog

  • Gray Treefrog

  • Cope's Gray Treefrog

  • Birdvoiced Treefrog

  • Chorus Frog

  • Spring Peeper

  • Illinois Chorus Frog

  • Green Frog

  • Southern Leopard Frog

  • Bullfrog

  • Wood Frog

  • Northern Leopard Frog

  • Northern Leopard Frog

  • Crayfish Frog

  • Plains Leopard Frog

  • Plains Leopard Frog


  • have permeable skin.
  • have permeable egg membranes.
  • are constrained to moist habitats.
  • have no tail as adults.
  • have a urostyle - fused vertebrae.
  • have elongated ankle bones.
  • have elongated tarsal bones.



There are approximately 6,300 species of frog in the world, 23 of which are found in Illinois.

Ranidae - True Frogsranaclamitans.png

  • have teeth on the upper jaw
  • Illinois species have webbed feet
  • Illinois species lay their eggs in water
  • over 600 species
  • found on all continents except Antarctica
Lithobates areolatus Crawfish Frog
Lithobates blairi Plains Leopard Frog
Lithobates catesbeianus Bullfrog*
Lithobates clamitans Green Frog*
Lithobates palustris Pickerel Frog
Lithobates pipiens Northern Leopard Frog
Lithobates sphenocephalus Southern Leopard Frog
Lithobates sylvaticus Wood Frog*

Pelobatidae - Spadefoot Toadsspadefoot.png

  • have teeth
  • named for keratinized "spade" on hind feet
  • found in North America, Europe, and Asia.
  • 11 known species
  • One Illinois species Scaphiopus holbrookii  Eastern Spadefoot

Microhylidae - Narrowmouth Frogs and Toadsgastrophryne.png

  • most have small pointy heads
  • most lack teeth
  •  only one species in Illinois Gastrophryne carolinensis Eastern Narrow-mouthed Toad


Hylidae - Tree Frogshyla.png

  • over 900 species on Earth
  • most are arboreal
  • have claw shaped terminal phalanges (last toe bone) because of cartilage between bones
  • many have toe-pads to help climb
  • found on every continent except Antarctica
 Acris blanchardi Blanchard's Cricket Frog*
Hyla avivoca Bird-voiced Treefrog
Hyla cinerea Green Treefrog
Hyla chrysoscelis Cope's Gray Treefrog*
Hyla versicolor Gray Treefrog*
Pseudacris crucifer Spring Peeper*
Pseudacris feriarum Upland Chorus Frog
Pseudacris illinoensis Illinois Chorus Frog*
Pseudacris maculata Boreal Chorus Frog
Pseudacris triseriata Western Chorus Frog*

Bufonidae - Toadsbufo.png

  • have no teeth
  • over 350 species
  • males have a Bidder's Organ, an undeveloped ovary
  • found naturally on every continent except Antarctica and Australia
  • introduced to Australia

 Illinois species have:

  • dry bumpy skin.
  • short hind legs.
  • enlarged parotoid glands at back of head.
  • spades on hind leg.

Anaxyrus americanusAmerican Toad

Anaxyrus fowleri Fowler's Toad