1. Faunal regions or Zoogeographical Regions
Present-day Mammalian Faunal Diversity

2. Zoogeography -study of the distribution of animals
-patterns and processes
-can be studied at many different scales
Chapter 26; Feldhammer text

3. Zoogeography A. Historical zoogeography
Examine evolutionary history of a group of animals
in the context of “earth history”
Geographic patterns of diversification, extinction etc.
Large geographic scales & “deep” time frames
B. Ecological zoogeography
What features of present-day environments restrict organisms
to their current environment?
Smaller spatial scales & more recent time frames (i.e., Holocene-present)

4. ALLOPATRIC SPECIATION
A. Historical zoogeography
Fundamental principle is VICARIANCE
Diversification (i.e., speciation) is primarily the result of widespread
populations being “split” by the formation of an environmental barrier C A
species X
species X B
Range of
species X
divided
species Y
species Z
environmental
barrier
forms
2 new species form via
ALLOPATRIC SPECIATION

5. Time frame Spatial scale Ecological Zoogeography Recent Small Large
Historical Zoogeography
Past
Combination: can tell us about the geographic history of a group
AND the relationship between present environmental conditions
& present mammal distributions

6. Faunal regions
Present-day Mammal Diversity

7. Palearctic: Eurasia, including North Africa and all of Europe and Asia
(north of India and tropical southeast Asia)
Palearctic
# families = 42
endemics = 0
largest faunal region in terms of area
Moderate familial diversity, but no endemic families
Shares ~ half of its families with the Nearctic

8. The Bering land bridge has been open for dispersal for periods of time during the Pleistocene

9. The Bering land bridge has been open for dispersal for periods of time during the Pleistocene

10. Nearctic: North America north of Mexico and Greenland
# families = 37
endemics = 2
2nd largest faunal region
Moderate familial diversity
Only 2 endemic families

11. Nearctic: North America north of Mexico and Greenland
Only 2 endemic families
Aplodontidae
Antilocapridae

12. Nearctic: North America north of Mexician lowlands and Greenland
Also shares about half of its families with the Neotropics
Connected relatively recently (ca. 3 MYA) with the Neotropical region
through the Panamanian land bridge

13. Neotropical: High familial diversity (50) Greatest number of endemic
Central Mexico throughout South America,
including the Caribbean islands
High familial diversity (50)
Greatest number of endemic
families (19)
Long period of isolation and a warm and favorable climate
has probably contributed to this

14. Neotropical Endemic Families
Bradypodidae Myrmecophagidae
Microbiotheriidae Callithrichidae

15. Ethiopian # families = 52 endemics = 18
D. Ethiopian: Africa south of the Saharan Desert; includes Madagascar
Connected to the Palearctic
via the Sahara
Ethiopian
# families = 52
endemics = 18
Madagascar
-lemurs & tenrec
radiation
Much tropical land mass
Much familial diversity, with many endemics (18)
Many endemic primates, and especially high endemism on Madagascar

16. Ethiopoan Endemic Families
Hyaenidae Orycteropodidae
Lemuridae Macroscelididae

17. Oriental # families = 50 endemics = 4
E. Oriental: Tropical southeast Asia, India, and southeast Asian islands including Borneo, Sumatra, some Indonesian islands and the Philippine archipelago (does not include New Guinea and Sulawesi)
Oriental
# families = 50
endemics = 4
Much of it is tropical
High familial diversity, but fairly low endemism

18. Neotropical Endemic Families
Tupaiidae Tarsiidae
Cynocephalidae

19. E. Oriental: Tropical southeast Asia, India, and southeast Asian islands including Borneo, Sumatra, some Indonesian islands and the Philippine archipelago (does not include New Guinea and Sulawesi)
mountains
sea
central position
Shares ~75% of mammalian families with the Palearctic, ~60% with the Ethiopian, and ~50% with the Nearctic
no endemic families!

20. F. Australian: Australia, New Guinea, and associated islands
# families = 28
endemics = 17
A long period of isolation with very low diversity but high endemism
Only 28 families, but 17 endemics
Shares <20% of its families with any other region

21. Australian Endemic Families
Tachyglossidae Ornithorhynchidae
Macropodidae Phalangeridae

22. G. Oceanic: The islands of the Pacific Ocean
Greatly isolated; generally only various species of bats make it onto these islands (we are not considering oceanic mammals here)

23. Plate tectonics is the study of the movements of crustal plates, upon which the continents ride
Continental drift is the movement (over geological time) of the continents

24. Plate tectonics is the study of the movements of crustal plates, upon which the continents ride
Continental drift is the movement (over geological time) of the continents

25. About 225 MYA, continents were joined together into a single
CONTINENTAL DRIFT
About 225 MYA, continents were joined together into a single
“supercontinent”:
PANGAEA

26. Laurasia: North America, Europe, Greenland, part of Asia
CONTINENTAL DRIFT
~200 MYA Pangaea began to break up into two large land masses:
Laurasia: North America, Europe, Greenland, part of Asia
Gondwanaland: South America, Australia, Africa, Antarctica, part of Asia

27. Much early evolution of mammals was going on
as the continents were breaking up still further

28. presence of marsupials in Australia and South America due to continents being isolated for long
periods
Australia stayed isolated, accounting for the large number of marsupials in Australia

29. isolated for a long time
South America was also
isolated for a long time
But, SA joined North
America via Panamanian
land bridge (3 MYA)
Panamanian
Land
Bridge
(3 MYA)
extinctions of many marsupials in SA as eutherians invaded
Only 1 marsupial reinvaded North America
Virginia Opossum

30. filter route Great American Interchange Few early dispersals
Entered NA & CA
from SA
Few early dispersals
beginning ~9 MYA
Reached peak ~3 MYA
Isthmus of Panama
emerged as dry land
filter route
Entered SA & from NA

32. Question: How did earth history, especially continental drift,
influence the geographic distribution and evolutionary
histories of the following?
AFROTHERIA!
METATHERIA!
XENARTHRA!

33. Pleistocene Zoogeography of Mammals
The last ~2 MY- characterized by repeated glacial
cycles, or “ice-ages”
Effects on mammals?????:
Major distributional shifts
Lots of extinction
Speciation???

34. Glacial Cycles of the Pleistocene
> 20 cycles during the past ca. 2 million years
~100,000 year periodicity
increased in intensity last 700,000 years
2.1 million year record
700,000 year record
Oxygen
isotope
record

35. Present global distribution of boreal (northern coniferous) forests