Class Amphibia I
Taxonomy
Characteristics
Gas exchange
Reproduction
Metamorphosis
Class Amphibia
Order Gymnophiona (Apoda):
Caecilians
Order Caudata: Salamanders and newts
Order Anura: Frogs and toads
Class Amphibia
Class Amphibia
Order Gymnophiona (Apoda): Caecilians
• legless, burrowing amphibians
• tropical
• 169 species
• not found in BC
All newts are salamanders!
Northern crested newt (Triturus carnifex)
Order Caudata: Salamanders and newts
•
•
•
•
•
tailed amphibians
fertilization mostly internal
aquatic, terrestrial or amphibious
525 species in 9 families
BC - 9 species in 4 families
Class Amphibia
Order Anura: Frogs and toads
• tailless amphibians
• fertilization mostly external
• 5006 species in 20 families
• BC - 12 species in 4 families
Rough-skinned newt
(Taricha granulosa)
Eastern newt
(Notophthalmus
viridescens)
1
Class Amphibia
Class Amphibia
• Lack fur, scales, feathers, claws or beaks
Taxonomy
Characteristics
Gas exchange
Reproduction
Metamorphosis
• Ectothermic
• Skin highly permeable to water and gases
• Great diversity of habitats
• Great diversity of reproductive modes
• Eggs must be in water or kept moist
(non-amniotic eggs!)
Class Amphibia
• Lack fur, scales, feathers, claws* or beaks
•
*except clawed frog
Class Amphibia
Salamanders
are not
lizards!
Class Amphibia
•Skin highly permeable to water and gases
•Ectothermic: use environmental
temperature to regulate body
temperature.
need water or moist conditions
Susceptible to air/water pollutants
Some behavioral regulation:
choice of locality within habitat
2
• Great diversity of habitats
Pacific treefrog
= Pacific chorus frog (Hyla regilla)
ponds
Riparian habitats
Bullfrog (Rana catesbeiana)
Elk Lake
Ascaphus truei, Tailed frog
(adult male)
Red-legged frog Rana aurora
cascading streams
Spea intermontanus, Great Basin
Spadefoot Toad
Western Red-backed salamander (Plethodon vehiculum)
Rain forest, Vancouver Island
Great Basin desert
3
Many tropical species
Class Amphibia
•Great diversity of reproductive modes
• variety of mating rituals
• internal/external fertilization
• oviparous/viviparous/oviviparous
• some species: foam nests, parental care…
Poison-dart frogs: Dendrobates
Class Amphibia
Mudpuppy (Necturus maculosus):
an aquatic species with gills
Taxonomy
Characteristics
Gas exchange
Reproduction
Metamorphosis
Hellbender (Cryptobranchus alleganiensis): an
aquatic salamander with lungs and folds of skin
Western Red-backed salamander (Plethodon vehiculum):
a lungless terrestrial salamander
4
Lungs and transcutaneous gas exchange
Pacific chorus frog
(Hyla regilla)
Class Amphibia
Taxonomy
Characteristics
Gas exchange
Reproduction
Metamorphosis
Pectoral (axillary) amplexus
Males call
females with
speciesspecific calls
Pelvic (inguinal) amplexus
African Clawed Frog
(Xenopus laevis)
Vieites, et al. 2004. Nature 431: 305-308
5
“Dual life” of a frog (Rana temporaria)
Neoteny – sexually mature larva
Frequent neotenic
individuals in:
NW salamander,
Giant salamander,
Tiger salamander
Developing eggs of Wandering Salamander
Van Dyke’s Salamander (Plethodon
vandykei) attending eggs
Salamander mating ritual
6
Frog eggs
Class Amphibia
Taxonomy
Characteristics
Gas exchange
Reproduction
Metamorphosis
tadpoles
salamanders
larva
anurans
tadpoles
7
Toads and garter snakes:
predator swamping
toads transform
synchronously to
overwhelm predators
8