Lecture 21- Amphibians Flashcards by Anna Julie Bohacova

What is the proportion of vertebrates are amphibians in Australia?

10%

-they are monophyletic, one origin (unlike reptiles= they are polyphyletic)

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What are the topics we do?

Amphibian history and relationships within the vertebrates

* Amphibian groups worldwide vs Oz • Australian frog groups & characteristics • Life cycles • Frog declines

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What are the amphibians? (evolution, limbs, where they live, ecto or endothermic)

• First vertebrate group to exploit the terrestrial environment
• Limbs (tetrapods) & lungs: terrestrial life
• Still dependent on moist environments - adults have highly permeable skin
- most sp. require water for reproduction (some exceptions) - eggs without shells
• Ectothermic

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What are the three orders of Amphibia?

1.order Anura - frogs & toads 2.order Caudata- newts & salamanders order 3.Gymnophiona - caecilians (legless)

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What is the only group of amphibians in Australia?

-Order Anura - only group of amphibians in Australia
• 21 families worldwide
• 5 families native to Australia

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What are the four division of frogs?

Limnodynastidae=limnodynastid frogs
Myobatrachidae=southern frogs 3.Hylidae=treefrogs 4.Microhylidae=tiny tree frogs/narrow-mouthed frogs
Ranidae=true frogs

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Where are there many frogs in Australia?

-in the north

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How many species are there in Limnodynastidae in Australia?

-40 spp.
-8 Genera
-Widespread distribution in Australia
(used to be in Myobatrachidae)

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What are the characteristics of Limnodynastidae?

All 40 species in Australia
Extensive adaptive radiation in Australia
Wide range of ecological and developmental specialisations
Variety of life history patterns
Most are burrowing or terrestrial, none are arboreal

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What is the Pobblebok (Banjo frog)?

Very common in south- eastern Australia
Range of habitats
Burrows
Very distinctive “bonk” call – chorus sounds like a banjo

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How many species are there in many Myobatrachidae in Australia?

88 spp.
13 Genera
Widespread distribution in Australia

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What are the characteristics of Myobatrachidae?

• All 88 species in Australia
• Extensive adaptive radiation
• Wide range of morphological, ecological and developmental specialisations
• Variety of life history patterns – from fully aquatic to fully terrestrial
• Burrowing and terrestrial
-Gondwanan

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What is the turtle frog like?

-Turtle frog Myobatrachus gouldii
•Strictly terrestrial – no aquatic phase in life cycle
• Often found in termite mounds or in burrows
-belong to Myobatrachidae

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How many species are the in the Hylidae?

73 spp.
3 Genera
Widespread in Australia

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What are the characteristics of Hylidae?

• Worldwide, but most in Australia and S. America • 73 species (3 genera) in Australia:
Litoria, Cyclorana & Nyctimystes
• Widespread & successful in Australia
• Typical water-dependent reproduction
• Morphological, physiological & behavioural adaptations to extreme environments
– arid zones – rainforests

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What is the Magnificent tree frog?

Magnificent tree frog Litoria splendida

- Discs/pads on ends of toes

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What is special about the Hylidae species Cyclorana?

-Some hylids evolved into a life far from the forests
Water-holding frog
Cyclorana platycephala

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How many species are there of Microhylidae in Australia?

-18 spp.
- 2 Genera
Distribution limited

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What are the characteristics of Microhylidae?

18 species (2 genera): Sphenophryne & Cophixalus

* Tropical northern Australia • Small, from 1 – 3 cm: hard to find unless calling • Direct development

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What are the nursery frogs?

-Cophixalus species
• Lay clutch in moist soil under rocks, leaf litter • Eggs coated with anti-fungal agent • Male guards eggs • Tadpole develops inside egg, froglet hatches out • Restricted distributions, some species very rare

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How many Ranids are there in Australia?

1 spp. 1 Genus

What are the characteristics of Ranidae?

Most successful family worldwide

* Only one species/genus in Australia: Rana daemeli (wood or water frog)

What is the most damaging introduced frog species?

-Cane toad Rhinella (Bufo) marinus
• Family Bufonidae • Introduced to Australia in
1935 to ‘control’ cane beetles
• Highly fecund: up to 25000 eggs/spawn
• Range expansion ~ 50km/yr – arrived in Kakadu NP 2001
• Poisonous glands: major problem for native wildlife

How far did the cane toads already get?

-Have now crossed the NT/WA border

What are the characteristics of cane toads?

- the big glands behind a cane toad's eyes release a poisonous milky liquid when the toad feels threatened - cane toad skin is dry and warty, rather than moist and slippery like many native frogs and usually in dull brownish colours - cane toad feet don't gave suckers on the end of the toes - cane toads have very distinctive bony rodges over their eyes. These ridges meet in the middle - the call of a male toad is like a high-pitched purr, a bit like a telephone dial tone - adult cane toads are heavily built and average from 100mm to 150mm

What Australian frog families are Gondwanan?

1: Limnodynatidae 2:Myobatrachidae 3: Hylidae

What Australian frog families are from Asia?

Microhylidae and Ranidae

What Australian frog family is introduced?

Bufonidae

What gender does the calling in frogs?

• Only males call: for mate attraction & announcement of territory • Frogs have selective hearing! -important in reproduction

What is the frog life generally dependent on?

- water | - usually egg to tadpole and undergo metamorphosis= frog

What is the life cycle like in Hylidae?

- typical frog pattern; lay eggs in water and tadpoles develop in water, non- foamy egg mass

What is the life cycle like in Myobatrachidae?

- wide variety of reproductive patterns: from water-dependent to water-independent

How many reproductive modes are there in frogs?

Ten reproductive modes: | tendency towards independence from free water for larval development

What are the reproductive strategies of Myobatrachidae?

- eggs or eggs in water+ foam or eggs on land, and on land+foam= all of these have tadpoles in water - can also have direct development (no feeding stage) where eggs are on land, on land and buried, brood pouches or in stomach

What are the reproductive strategies in Hylidae?

-can have eggs in water or on land with tadpoles in water

What is the reproductive strategy of the Ranidae?

-eggs in water and tadpoles in water

What is the reproductive strategy in Microhylidae?

-direct development, no feeding stage with eggs on land

What families have mode I: eggs in water, non-foamy egg mass, tadpoles in water?

-Hylidae, Myobatrachidae, Ranidae

What families have mode II: eggs in water, foamy egg mass, tadpoles in water?

Myobatrachidae

What families have mode III: eggs on land, in burrow or vegetation with tadpoles in water?

Hylidae and Myobatrachidae

What families have mode IV: eggs in a foamy mass in burrow with tadpoles in water?

Myobatrachidae

What families have modes V, VI and VII: direct development without a feeding stage, hatches from capsule/ foamy and /or nest?

Myobatrachidae, Microhylidae

What families have mode VIII: direct development without a feeding stage, eggs deep under soil (up to 1.2m) intra-capsular development?

Myobatrachidae

What families have mode IX: direct development without a feeding stage, male carries larvae in brood pouches?

Myobatrachidae

What families have mode X: direct development without a feeding stage, female carries larvae in stomach?

Myobatrachidae

What are the extremes of water independence and parental care in frogs?

Myobatrachid frogs: • Assa darlingtoni “marupsial frog”; males carry developing tadpoles in brood pouches. Very small distribution: NSW-Qld. border • Reobatrachus spp. – gastric-brooding frogs from Queensland rainforests

How does Assa darlingtoni develop?

- adult and eggs - 11.5 days: male + embryos - embryo enter pouch - 62 days= emerging froglets

What is the northern gastric brooding frog?

(Rheobatrachus vitellinus): last seen in the wild 1985

What is the conservation status of frogs?

* Sudden, dramatic decline in frog numbers in many countries – commenced late 1970s * Frog declines noted throughout Australia, mostly QLD, NSW, VIC. * Australia: 27 species endangered, rare or presumed extinct * Are declines caused by humans or a natural phenomenon?

Why have frog populations been declining?

• Climate change? - elevated temperatures: water loss • Habitat loss and fragmentation? - e.g. effects of timber harvesting on spotted tree frog in Vic. • Disease? - chytrid fungus

Summary:

• Only one order: Anura (Frogs) in Australia • Wide diversity within that order – 3 families Gondwanan origins – 2 families Asian origins – 1 family introduced by Europeans • Diversity in reproductive patterns • Global declines of frogs