Order Anura Frogs

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Order AnuraFrogs Toads

• Fred Searcy
• ZOO2010

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Anura(Gr an without oura tail)

• Frogs vs Toads
• Frogs typically
• Have smoother, slimier skin
• Lay eggs in stacks or masses
• Are skinnier with longer legs
• Move primarily by leaping
• Live closer to water
• Toads typically
• Have rougher (warts), drier skin
• Lay eggs in strings or straight lines
• Have a stouter body, shorter legs
• Move primarily by walking or shorter hops
• Live further away from water

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Habitats Distribution

• Temperate, subtropical and tropical regions
• None in New Zealand, Oceanic islands and southern
  South America
• In temperate regions hibernate in soft mud at
  bottoms of streams and lakes
• Metabolic rate decreases
• Live off stored glycogen and fat
• Tree frogs hibernate in humus on forest floor
• Some frogs toads are freeze proof

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Integument

• Skin loosely attached only at certain points
• Epidermis contains keratin
• Dermis
• Glands
• Mucous produce a slimy waterproofing
• Serous abundant around neck and head region
  called parotid glands
• White watery poison
• Chromatophores (also extend into epidermis)
• Xanthophores (yellow, orange, red)
• Iridophores (metallic)
• Melanophores (black and brown)

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Skeletal System

• Endoskeleton of bone and cartilage
• 9 trunk vertebrae
• Caudal fused to form urostyle
• Limbs at right angles to the body

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Muscular System

• Not in myomere form of fish
• Dorsal muscles hold and support head and
  vertebral column
• Ventral muscles well developed to support
  internal organs
• Axial muscles
• Anterior-ventral pull limbs forward
  (protraction) and to the midline (adduction)
• Posterior-dorsal works in opposition back
  (retraction) and away (abduction)

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Respiration

• Three structures
• Skin
• Buccal membranes
• Lungs
• CO2 lost through the skin
• Positive pressure lungs
• Air pulled in by lowering floor of mouth to bring
  air in through nostrils
• Nostrils close and glottis opens
• Floor of mouth raised and air pushed into lungs

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Vocal Cords

• Both sexes produce sounds but males have better
  developed larynges
• Air forced over
• The cords from lungs
• Buccal pouches in floor of mouth
• Buccal pouches often used as resonance chambers
• Most vocal during breeding season

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Circulation

• Closed circulatory system
• Arteries
• Veins
• Lymph vessels
• Three chambered heart

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Heart

• Problem with mixing of oxygenated and
  deoxygenated blood
• Partition between atria but not in ventricle
• Deoxygenated blood enters heart through swelling
  of vessels at the top of the heart called the
  sinous venosus
• Enters right atrium
• Left atrium receives oxygenated blood from lungs.
• Both atria contract at the same time, therefore
  both oxygenated and deoxygenated blood enters the
  ventricle
• As it is pumped out the ventricle, enters the
  conus arteriosus
• Spiral valve in conus separates oxygenated from
  deoxygenated blood

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Nutrition

• Carnivorous
• Insects, worms, snails, small arthropods
• Large species may eat birds
• Protrusible tongue
• Attached to front of the mouth
• Sticky secretions
• Teeth hold prey in
• Premaxillae
• Maxillae
• Vomers
• Less lengthy digestive tract (proteins of
  animals)
• Tadpoles mostly herbaceous
• Sucker like disk allow them to attach to
  vegetation
• Longer digestive tract (plants)

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Nervous System

• Brains three regions
• Forebrain (telencephalon)
• smell
• Midbrain (mesencephalon)
• vision
• Hindbrain (rhombencephalon)
• Cerebellum (equilibrium movement)
• Medulla (all other sensory neurons except sight
  and smell)
• Spinal cord controls many responses
• Movement of limbs
• Beating of heart
• Lung functions

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Auditory Sensations

• No lateral line
• Sound detected through middle ear
• Stapes transmits sound to inner ear
• Middle ear covered by tympanic membrane
• Inner ear contains
• Utricle
• Three semicircular canals
• Saccule with out pocket called lagena covered by
  tectorial membrane
• Tectorial membrane rests on bed of hairs
• Detect low frequency sounds (lower than 4000 hz)

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Vision

• Terrestrial existence required greater
  modification from aquatic environment
• Lachrymal glands to keep eyes moist
• Eyelids
• Cornea an additional light bending structure
• Accommodation
• Unlike reptiles, birds, and mammals, the lens is
  actually moved
• Color vision (rods cones)
• Nictitating membrane

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Other Sensory Receptors

• Tactile and chemical receptors
• Taste buds on tongue and palate
• Olfactory in nasal cavity

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Reproduction

• Spring
• Males call to attract females
• Amplexus
• Telolecithal development
• 6-9 days later, tadpole emerges
• Complete metamorphosis may be finished in 3
  months
• Bull frogs may need 2-3 years