Week 2 Flashcards by Phoebe Waller

Metatheria

Infra class for marsupials - that give birth to partially developed young ones

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Eutheria

Placental mammals

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!Marsupial origin

North America

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!Convergent evolution between Australian marsupials and placental mammals, 6 examples.
Kangaroos -
Wallabies -
Wombats -
Koalas -
Numbats -
Diprotodonts (extinct) - 
What are the placental mammals equivalants?

Kangaroos - Antelopes 
Wallabies - Rabbits
Wombats - marmots
Koalas - sloth 
Numbats - Anteater 
Diprotodonts - Rhino and Tapir

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!Marsupial 7 orders

Diprotodontia - diproyodonts 
Dasyuromorphia - marsupial carnivore
Didelphimorphia - marsupial carnivore
Paucitubercultata - opossums and the rest
Microbiotheria - opossums and the rest
Peramelemorphia - opossums and the rest
Notoryctemorphia - opossums and the rest

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!Why aren’t there marsupial aquatic mammals?

Marsupial young are often held in pouches and Martine mammals would struggle to have pouches. (However there is a semi-aquatic possum called Yapok)

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!Economic importance of marsupials

Kangaroos hunted for hide and meat
Brush tailed possums are reared as fur bearers. They have become introduced pests, especially New Zealand, which has caused ecological and economical damage

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Theria

Subclass containing the metatheria (marsupials) and eutheria (placentals)

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Prototheria

Subclass for prototheria (monotremes)

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!Evolution of pouches

Absence of pouch is the ancestral or primitive condition
Pouches have evolved independently many times
50% of marsupials don’t have a pouch

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!Wombat pouch

Wombats have a backward opening pouch so that dirt doesn’t enter the pouch while digging.

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!Distribution of marsupials

Mainly southern hemisphere
Australia and New Guinea (200 species)
North & South America (70 species)

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!Lifestyle

Very diverse
Adaptations for..
Fossorial - burrowing
Ambulatory - walking
Cursorial- running
Saltatorial - leaping
Semi-aquatic - frequently living in water
Arboreal - inhabiting trees
Gliding

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!Diet

Very diverse
Insectivorous
Carnivores
Omnivores
Herbivores
Nectarivorous
Browsing and grazing

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Differences between marsupial and eutherian skulls and brains?

In marsupials:
Palate of marsupials is fenestrated (2 extra holes)
Dentary angle is “bent”

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Marsupials dentition

Upper jaw had more incisors than lower jaw (except wombats)

Cheek teeth typically 3/3,4/4

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What orders have diprotodont dentition?

Diprotodontia

Paucituberculata

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What is diprodont dentition?

Lower jaw shortens

Pair of lower incisors enlarge and elongate

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Epipubic bone

A characteristic of marsupials.

A bone which project anteriorly (stick forward) from the pelvis

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!Limb forms types

Marsupials show:
Plantigrade (majority) - walking on Palms/soles
Digitigrade - walking on fingers/toes
Water opossum has webbed hind feet to be semi-aquatic.
The hallux (big toe) is clawless

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Syndactylous feet: what is it and in which orders?

Found in orders:
Peramelemorphia
Diprotodontia
It is:
2nd and 3rd toes are fused. Separate sets of bones exist but are enclosed within a single skin sheath

Two most distinguishable features of marsupials from eutherians?

Syndactylous feet

Diprotodont dentition

!Marsupial reproductive development of young

Via lactation instead of placenta

Due to low birth weight of young and very short gestation

!Female marsupial reproduction

Have a double reproductive tract.

Birth takes place in median canal called the pseudovaginal canal

!Male marsupial reproduction

Scrotum anterior to the penis. | Penis bifurcates in majority of species

!Examples of marsupial species in the order Diprotodontia?

Possums Kangaroos Wombats Koalas

!Diprotodontia distribution

Australian faunal region - included Tasmania & islands to the north of Australia e.g. new Guinea.

!marsupium

Pouch

Distinguishing characteristics of diprotodontia

syndactylous hindtoes | Diprotodont teeth

Schizodactylous forefeet

Arboreal diprotodonts (e.g koala) have forefeet where the first two digits oppose (face the other way) to the other 3

!Diprotodontia families

Pseudocheiridae - ring-tailed possums Phalangeridae - cuscuses, brush-tailed possums Burryamidae - pygmy possums Petuaridae - striped possums, gliding possums Potoridae - "rat" kangaroos Macropodidae - kangaroos and wallabies Phascolarctidae - koalas Vombatidae - wombats Tarsipedidae - honey possum/noolbenger Acrobatidae - feathertail glider & feathertail possum

Ring tailed possum (order diprootodontia) adaptations

Ring tailed possum and greater glider Arboreal folivores Adaptation for folivory: *Enlarge caecum for microbial fermentation of high cellulose diet * Slow movement (because plant material doesn't provide much energy) *Coprophagy (helps with digestion)

!Pygmy possum (diprotodontia)

Pygmy possum Arboreal nectivores Adaptations: *High nitrogen diet allows for large little sizes *Extremely mobile to allow access to flowers *Small size

Striped possums and gliding possums (order diprootodontia) adaptation

Striped possums and gliding possums Arboreal Adaptations: *Use patagium to glide

Honey possum (order diprootodontia) adaptations

Honey possum Nectar and pollen specialist Because it eats pollen it had a reduced dental formula and a long tongue with brush-like tip.

Feathertail glider possum (order diprootodontia) adaptations

Feathertail glider possum: * nectivore * Brush-tipped tongue * Highly mobile and can glide

!Phalangeridae (order diprotodontia)

Cuscuses and bushtail possum | Enlarged lower premolar (projects above the level of other cheek teeth)

!Phalangeridae (order diprotodontia)

Spotted cuscus and dwarf cuscus etc

!Potoridae (order diprootodontia)

Bettongs, potoroos, and rat kangaroos

!Macropodidae "big-footed" (order diprootodontia)

Kangaroos and wallabies Largest and diverse marsupial family Adapted for saltatorial (bounding) and ricochetal (jumping) locomotion

!Dendrolagus in family macropodidae (order diprootodontia)

Tree kangaroos | There was an arborial niche that was free to fill in terms of leaf eating and fruit eating

!Phascolarctidae (order diprootodontia)

Koala (monotypic family) Feeds on eucalyptus Wife distribution along the East coast of Australia. Koalas from the south are much larger due to the cold.

!Dasyuromorphia "bushy tails" families

Dasyurodae - antechinus, quolls, devil etc Thylacinidae - thylacine Myrmecobiidae - numbat

Dasyuromorphia "bushy tails"

Order for marsupial carnivores

!Family Thylacinidae in order dasyuromorphia

Thylacine | Extinct

Numbat diet (order dasyuromorphia)

Numbat | Diet: termites

!Family dasyuridae in order dasyuromorphia

Antechinus, kowari, quolls, devil | Distribution: Australia and New Guinea - dry grassland to rainforest.

!Order Didelphimorphia

American opossum Distribution: south, central, and north America Habitat: grassland - rainforests Lifestyle: arboreal, terrestrial, semi-aquatic Diet: omnivores

!Order Paucituberculata

Marsupial shrews/rat opossum Distribution: Andean region Dentition: diprotodont

Monito del Monte (Order microbiotheria) adaptation

Monito del Monte | Adaptations: fat store in tail which provides energy to survive winter hibernation.

Marsupial mole (order Notoryctemorphia) adaptations

Marsupial mole Adaptations: Neck vertebra are fused which are adaptations to a fossorial lifestyle