ZOOL 224 Biogeography of Mammals

Where are monotremes found today and where have they been found?

Australia, Tasmania, New Guinea.

Fossils from Palaeocene in South America.

Where are marsupials found?

Australia, Tasmania, New Guinea, some in North and South America

What is the most primitive marsupial?

Didelphimorphia

Where are Didelphimophia found?

South and Central America to Mexico/USA.

Where are Paucituberculata found?

South America. Females lack pouch.

Where are Microbiotheria found?

South America (Chile and Argentina)

Microbiotheria have opposable __ and ___

Pollex and hallux (thumbs and big toes)

Where are Dasyuromorphia found?

Australia and New Guinea. Many lack full pouch.

Where are Notoryctemorphia found?

Australia and New Guinea. Marsupial moles.

Where are Peramelemorphia found?

Australia and New Guinea.

Where are Diprotodontia found?

Australia and New Guinea.

What are the 2 major characters of modern marsupials?

-Diprotodonty

-Syndactyly

What marsupial orders have diprotodonty?

-Diprotodontia

-Paucituberculata

What is diprotodonty?

Single pair of procumbent (grow outward laterally) lower incisors.

What amrsupial orders have syndactyly?

-Peramelemorhphia

-Diprotodontia

What is syndactyly?

Second and third toes enclosed under single shealth of skin. Look fused except for claws.

Describe the migration of marsupials in simple terms

Single migration from South America to Australia. 4 Australian orders share a single origin with Microbiotheria (found in SA). Didelphimorphia are the first branch of the marsupial tree.

Outline the movement of marsupials

Asia > NA > SA (true marsupials show up around here) > Australia

How did marsupials enter Australia?

From Antarctica before it branched off 50 mya.

How did marsupials get to New Guinea?

Probably on a raft or swam.

What was the main event that led to diversification of mammals in the Americas?

Great American Biotic Interchange/Schism

NA and SA were separated until _ mya

3 mya

What caused the connection of NA and SA?

Volcanic Isthmus of Panama

What epoch did the connection of NA and SA happen in?

Pliocene

What animals domianted Pro Pliocene SA?

-Borhyaenids

-Meridiungulates

-Xenarthrans

-Some placentals

Prior to reconnection fo N and S America, there was migration via ___

Island hopping. Ground slothes went north and procyonid racoons went south.

Why were North American forms more successful in migration compared to South American forms?

North American fauna could have come from Eurasia and had much larger land and variable climate. They were better suited and better at competition. South american fauna were more isolated.