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71 Cards in this Set

  • Front
  • Back

When did reptiles originate?

Late Carboniferous period (300mya)

Why did reptiles originate?

Expansion of insect orders due to increasing quantity and diversity of vegetation created a potential food source for a carnivorous vertebrate

What is the Age of Reptiles?

Extensive radiation of reptiles when they dominated life on land

Jurassic-Cretaceous, lasted 165my

Changes associated with life on land

Lungs and internal nostrils for breathing air

Increased efficiency in vascular system

Loss of gill and opercular bones

Impermeable skin to avoid dessication

Strengthened skeleton

Improved locomotory muscles

Limbs replace fins

Mobile neck


No aquatic larval stages

Miniature adults born

Eggs used to a greater or lesser extent

Cleoidoic/amniotic egg

Key step in making reptiles independent from water

Contains food and protective membranes for supporting embryonic development on land

What 3 main needs of the embryo must a terrestrial egg meet?

Prevention of desiccation

Exchange of respiratory gasses

Disposal of excretory products


Occurs in most reptiles and all birds

Eggs deposited in soil or nest

Exchange water and gases with environment

Sometime there is maternal care (birds-always)

Young are independent at birth (birds-need care)

Reptile eggshell

Low calcium -> soft, flexible, permeable to water

Eggs usually deposited in damp soil and grow during incubation at rates dependent on temperature

Temperature of incubation may determine the sex of the hatchling

Bird eggshells

Shell has higher calcium -> hard, impermeable to water

Eggs usually incubated at constant warm temperatures by parents


Some lizards and snakes

Eggs are retained in oviduct but are nutritionally self-contained

Yolk sustains the embryo rather than food from the mother, exchange water and gases with mother

Born live


Some lizards and snakes

Shell never forms

Eggs retained in oviduct

Yolk size is variable

Young receive some nutrition from the mother

If large amount of nutrition are required a placenta forms to enable exchange of materials between mother and embryo


Need to be internal

All extant reptiles except tuatara have an intromittent organ, either a single penis of a paired hemipenes


Jaw muscles enlarged and arranged for better mechanical advantage

Kinetic skull

Hinges at front and back of skull

Allow skull to change shape, better potentialto manipulate prey once caught, allows skull to bend producing a large gape


Tough, dry, scaly -> prevention against desiccation and injury

Few glands

Keratinised scales

Keratinized scales

Derived from epidermis

Not homologous to dermal fish scales

Crocodile scales

Remain throughout life

Gradually grow

Lizards and snakes

Scales are periodically shed


New layers of keratin are added under platelike scutes


3-chambered heart

Right atrium is partitioned from the left

Complete ventricular separation in crocodiles

In others flow patterns prevent mixture


Gill slits present only in embryos, never functional

Suck air into lungs by enlarging thoracic cavity, snakes and lizards use rib cage, turtles and crocodiles move internal organs

Cutaneous respiration is not used

No muscular diaphragm

Water conservation

Have a metanephric kidney

Many have slat glands near nose and eyes to excrete salts

Nitrogenous waste excreted as uric acid - easily precipitates out of solution, conserves water

Strengthened skeleton

Skeleton well ossified

Rib with sternum forming a complete thoracic basket

Limbs paired, usually 5 digits

Adapted for climbing, running or paddling

Reptilian limb design

Most modern reptiles walk with splayed legs and belly close to the grounds

A few modern lizards and most dinosaurs walked on upright legs

Nervous syste

Relatively large cerebrum

Connections to the central nervous system are more advanced permitting more complex behavior

Lateral line organs lost

Sense organs well developed

Ectothermal thermoregulation

Gain or lose heat by convection, conduction, evaporation or metabolism

Behavioural thermoregulation

Movement between shade or sunlight

Orientation - parallel to perpendicular to sun

Colour change

Reptile skull

Generally higher and narrow than in amphibians

Number of bones is reduced


Openings which allow jaw muscles to enlarge and bulge out

Edges of fenestrae are attachment sites for those muscles

Anapsid skull

No fenestrae

Earliest reptiles - order Cotylosauria

Turtles and tortoises - order Testudines

Synapsid skull

1 fenestrae high on cheek

Subclass Synapsida

All synapsids are extinct except for the mammals

Euryapsid skull

1 fenestrae high on cheek

Subclass Icthyopterygia

Subclass Euryapsida

Diapsid skull

2 fenestrae, 1 low 1 high

Subclass Lepidosauria

Subclass Archosauria

Order Cotylosauria

Originte from labyrinthodont amphibians

Carboniferous to Triassic

Order Testudines

Triassic to present

Emarginated skull

Horny beak, no teeth

Heavy body armor for protection - have long mobile neck which can be withdrawn into shell by bending in S-shapes, breathe by thoracic pumping, limb movement, or cloacal respiration

Order Pelycosauria


Generalised reptiles

Trends toward mammalian features


Heterodont teeth

Order Therapsida

Hervorous forms - reduced or no teeth, horny beak

Carnviorous forms transitional to mammals

Subclass Icthyopterygia



Extension of the finger bones to support fins

Homodont teeth on long beak-like skull


Subclass Euryapsida

Order Protosauria: lizard-like terrestrial reptiles

Gave rise to Sauropterygies: amphibious or fully marine

Subclass Lepidosauria

Order Eosuchia

Order Sphenodontia

Order Squamata

Order Eosuchia

Extinct order

Lizard-like, quadrupedal, terrestrial, aquatic

Thecodont (socketed) teeth

Fully diapsid skull

Order Sphenodontia

Fully diapsid skull

Acrodont teeth (fused to jaw)

No intromittent organ in male

Order Squamata

Bodies covered with horny epidermal scales

Teeth acrodont or pleurodont

Reduced diapsid skull

Kinetic skull

Suborders of Order Squamata





Suborder Lactertilia


Infratemporal arcade lost

Terrestrial, arboreal, semi-aquatic

Geckos, iguanids, skins, chameleons

Moveable eyelids

Ears not usually important

Can live in arid conditions


Small, agile, mostly nocturnal

Toe pads to allow climbing


Often brightly coloured with ornamental crests


Elongated bodies



Accurate sticky tongue

Suborder Ophidia

Both arcades lost, also sternum, pectoral girdle and sacrum

Highly skinetic skulls with symphysis of jaws - each operates independently when swallowing prey

Elastic skin

No secondary palate but trachae can extrude from mouth to breathe while swallowing

One lung

Sperm storage

How do snakes hunt?

Hunt prey chemically - olfactory, Jacobsen's organs

Flick tongue transfers scent particles to Jacobsen's organs in the mouth

Suborder Amphisbaenia

Highly specialised burrowers

Lack external limbs

Solid skull used for digging

Feed on invertebrates

Subclass Archosauria

The ruling reptiles

Many large and bipedal

Thecodont teeth in some, horny beaks in others


Five orders, order Order Crocodilia surviving

Order Crocodilia

Largely unchanged since early Mesozoic

21 surviving species

Three families - alligatores and caimons (Americas), crocodiles (widespread), gavials (Burma)

Elongate robust skull

4 chambered heart

Complete diaphragm


Order Thecodontia

Lizard-like or crocodile-like

Tendency to bipedalism

Order Pterosauria

Flying reptiles

Keeled sternum

Wings supported by elongated limb bones

Elongated skull

Homodont or absent teeth

Long tail for stability

Slender legs

Excellent gliders,weak fliers

Two main dinosaur lineages

Order Saurischia

Order Ornithischia

Order Saurichschia

Triradiate pelvis

Suborder Sauropoda: quadrupedal, amphibious, herbivores

Suborder Theropoda: bipedal, terrestrial, carnivores, ancestors of birds

Order Ornithischia

More complex tetraradiate pelvis

All large and herbivorous

Both bipedal and quadrupedal forms

Suborder Ornithopoda - duck billed dinosaurs

Suborder Stegosauria - armoured dinosaurs

Suborder Ankylosauria - armorued dinosuars

Suborder Ceratopia - horned dinosaurs

Characteristics of NZ reptiles

Isolated and small

Relatively fe groups

16 extinct orders

What are the living reptile orders in NZ?



Marine turtles

Marine crocodiles

Order Crocodilia in NZ

21 species worldwide

Australia salt-water crocodile may sometimes wander nto NZ water

Order Testudines in NZ

Three species are found in NZ waters: Leathery turtle, Pacific loggerhead turtle, green turtle

Hawksbill turtle and Olive Ridley turtle occasionally visit

Order Sphenodontia in NZ

Only species in Sphenodon punctatus

Restricted to 32 islands

Most of STephen's island

Suborder Ophidia in NZ

Until recently illegal in NZ

3 species of sea snakes in 2 families

Suborder Lactertilia in NZ

About 100 extant species - geckos and skinks

High diversity

Equal in diversity to endemic land birds

Many species per genus

High local diversity

Great antiquity

Many species now restricted to islands

High habitat diversity

High longevity

Highly philopatric


Family Gekkonidae in NZ

Viviparous in NZ unlike in the rest of the world

Non-vocal unlike in other areas

Family Gekkonidae characteristics


Large eyes

Transparent scales

Distinct diamond-shaped head

Skin soft, loose, matt


Family Scincidae characteristics


Skin firm and tight

Scales flat, shiny, overlapping

Head not differentiated from body

Conservation of NZ lizards

Reduction in number and extinctions due to introduced mammals

Many species restricted to islands

Habitat modification and destruction


Largest species are extinct

Nocturnal species more vulnerable