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BSC Zoology - Australian Flora and Fauna > Lecture 22- Reptiles > Flashcards

Lecture 22- Reptiles Flashcards

1
Q

What is special about reptiles?

A

First really successful colonisers of earth’s terrestrial environments

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2
Q

What are scales for in reptiles?

A

scales: prevent water loss (not permeable)

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3
Q

What is the egg of reptiles like?

A
  • amniotic egg: embryo in fluid-filled sac (+ shell), thus more resistant to drying compared with amphibians
  • must have internal fertilisation
  • gives you resistance to drying out
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4
Q

What are the water conservation characteristics of reptiles?

A

• Excrete urea (thick paste) reduces water loss (not urine)
• Faeces very dry (water conservation)
• Ectotherms: constrains activity, but also means energy requirements relatively low (most reptiles can go for considerable periods without feeding)
=Characters make reptiles well suited to exploiting terrestrial and in particular arid environments

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5
Q

What are the four orders of reptiles?

A
  • Order Crocodilia: crocodiles & alligators
  • Order Chelonia: turtles & tortoises
  • Order Squamata: snakes & lizards
  • Order Rhyncocephalia: tuatara (NZ only)
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6
Q

Are reptiles monophyletic?

A

-no
• Squamata: lizards + snakes
• crocodiles are closest to birds and dinosaurs (Archosauria)
• turtles branched early from the stem leading to archosaurs and lepidosaurs

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7
Q

What is the ancestor of all reptiles and birds?

A

-Sauropsida: ancestor of all reptiles and birds

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8
Q

How is Australia a land of reptiles?

A

-825 described species in Australia (North America 280 spp.) - Desert and tropical “hotspots”

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9
Q

How many crocodile species are there in Australia?

A

1 Family, 1 Genus, 2 Species

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10
Q

How many turtle species are there in Australia?

A

4 Families, 12 Genera, 22 Species

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11
Q

How many squamate species are there in Australia?

A

13 Families, 129 Genera, 801 Species

-snakes and lizards

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12
Q

What are the characteristics of crocodiles?

A
  • Heavily armored body, long jaws, streamlined body, powerful tail
  • Aquatic predators
  • Ancient – 240 million years old
  • Tropical distribution
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13
Q

What are the two species of crocodiles in Australia?

A
  1. Crocodylus porosus saltwater crocodile “saltie”=(max 7m) are extremely dangerous
  2. Crocodylus johnstoni freshwater crocodile (endemic to Australia) “freshie”= feed on fish
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14
Q

What is maternal care like in crocodiles?

A

• All lay eggs, advanced maternal care, sit with the eggs, carry young to the water

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15
Q

What Families of Turtles are there in Australia? (freshwater)

A
  • 4 families in Australia, have marine and freshwater
  • Chelidae: side-necked turtles (Gondwanan), fresh water species, more spread
  • Carettochelydidae- pitted-shelled (pig nosed) turtle – freshwater sp., limited radiation
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16
Q

What Families of Turtles are there in Australia? (saltwater)

A
  1. Family Cheloniidae- marine turtles, everywhere in the sea

2. Family Dermachelydae- marine, also everywhere in the sea, the Leatherback turtle

17
Q

How many families of lizards are there in Australia?

A
  • 7 families

- most with legs but some without

18
Q

What are the characteristics of Dragons (family of reptiles)?

A
  • Australia: 15 genera, 50 species (320 worldwide)
  • Australian group largely endemic
  • Typically: strong legs, fast moving, sun-loving lizards
  • All oviparous – eggs in burrows
  • Visual displays during courtship including head bobbing, arm waving
19
Q

What are the characteristics of Geckos (family of lizards)?

A

Australian geckos recently divided into 3 families:
Geckkonidae, Diplodactylidae & Carphodactylidae
• 25 genera, 114 species (800 worldwide) • Most diverse in arid & tropical areas, none in TAS • All Australian geckos are nocturnal • All oviparous: 1 - 2 eggs/clutch • Some parthenogenic • Highly vocal • Tail autotomy

20
Q

What is special about geckos?

A

-have “sticky feet”

21
Q

What are the characteristics of Pygopodidae? (family of lizards)

A 
• 7 genera 42 species in Australia
Thick-tailed gecko
Knob-tailed Gecko
Knob-tailed gecko
• Endemic to Australia and PNG, none in TAS
• Closest relatives to geckos (some older Australian gecko groups now classified with pygopodids)
• Tail autotomy
• 1 – 2 eggs/clutch
• Vocal
• No forelimbs
• Hind-limbs: reduced to small flaps
22
Q

How do you recognise if it is a legless lizard or a snake?

A

1: Legless lizards have hind “leg” flaps
2. Legless lizards have external ear
3: Legless lizards: have a fleshy tongue
4. Snakes: have a slender forked tongue

23
Q

What are the characteristics of Scinidae? (family of lizards)

A
  • Skinks, blue-tongues and stumpy-tailed lizards • 41 genera 389 species (> 1000 worldwide) • Most diverse lizard family worldwide • Largest group in Australia – occur everywhere • Highly variable in morphology, ecology etc.
  • Both oviparity (eggs) and viviparity (live young) • Some have reduced limbs
24
Q

What are the characteristics of Varanidae- monitors/goannas? (family of lizards)

A

• 1 genus (Varanus) 29 species (approx 38 worldwide, includes
Komodo dragon)
• Widespread worldwide, but Australia stronghold for family
• All oviparous – up to 35 eggs/clutch
• Perhaps the closest relatives to snakes (both have forked tongue)

25
Q

How many families of snakes are there in Australia?

A
  • 6

- no legs

26
Q

What are the characteristics of Typhlopidae – blind snakes?

A
  • 1 genus 44 species (approx. 150 worldwide)
  • Light sensitive eye spots
  • Insectivorous
  • Rarely seen – small, nocturnal & burrowing
  • Oviparous? • Little known family
27
Q

What are the characteristics of Boidae - pythons?

A

• 5 genera 15 species (25 worldwide)
• Most diverse in north
• Large, muscular snakes (up to 7 m)
• Mostly nocturnal, heat-sensitive pits for detection of vertebrate prey
• Kill prey by asphyxiation (constriction) • Oviparous
-can eat large prey: Olive
python Liasis olivaceus and common wallaroo (~35 kg)

28
Q

What are the characteristics of Acrochordidae – file snakes?

A

• 1 genus, 2 spp. • Wholly aquatic:
- 1 marine, northern Aust.
- 1 freshwater, tropical lagoons northern Aust.
• Fish-eaters (rough skin) • Viviparous • Quite recent arrivals

29
Q

What are the characteristics of Colubridae?

A
  • 6 genera 12 species (> 1600 worldwide)
  • Only northern and eastern coastal Australia, mostly arboreal and semi-aquatic
  • Very recent arrival in Australia – only one endemic species
  • Display both oviparity and viviparity
30
Q

What are the characteristics of Elapidae venomous land snakes & now includes the sea snakes?

A
  • 39 genera 138 species • Front-fanged • Radiated into all Australian habitats
  • Includes all the venomous terrestrial species + many non-dangerous species
  • Australia has 10 most venomous snakes in the world
  • Both oviparity and viviparity
31
Q

What is the Bandy-Bandy?

A

-(Elapidae)
Specialise in feeding on blind snakes
-the black and white banded snakes

32
Q

What are the characteristics of sea snakes?

A

-(both groups of sea snakes classified with Australian elapids)
SF: Laticaudidae (sea kraits) • 1 genus, 2 species
• Come ashore to lay eggs
SF:Hydrophiinae (sea snakes) • viviparous • 12 genera, 31 species • Wholly aquatic - live young

33
Q

What type of reproduction do reptiles have?

A
  • oviparity or viviparity
34
Q

What is oviparity?

A
  • Ancestral condition was oviparity
  • Many modern species remain egg-layers
  • Most lay eggs in burrow, some goannas lay in termite mounds
  • Pythons: incubate eggs
35
Q

What is viviparity?

A

• Some snakes and lizards have evolved viviparity
Young being born live
• Viviparity has evolved independently > 100 times in reptiles worldwide
• Most common in southern, colder areas
• Suggests evolution due to thermal constraints on embryogenesis

36
Q

How is sex determined in reptiles?

A
  • in some groups
    is temperature-dependent (TSD) In marine + pitted-shelled turtles: below 30C= all males, 30-32=males and female, above 32= all females
    -Family Chelidae: genetic sex determination
37
Q

What is the sex determination in freshwater crocodiles?

A
  • below 30C all females
  • 30-32 some males
  • above 32 all females
38
Q

Summary?

A
  • Wide diversity of reptiles in Australia – highly successful gp.
  • Crocodiles: 1 family
  • Turtles: 4 families
  • Lizards: 7 families -Snakes: 6 families
  • Not a monophyletic group
  • Both oviparity and viviparity TSD occurs in turtles and crocodiles

BSC Zoology - Australian Flora and Fauna (36 decks)

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