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The Six Faunal Regions

The Six Faunal Regions. Nearctic (us) Palearctic More species than Nearctic because larger Neotropical (most species) Tropical regions have more species than temperate regions More species than other tropical regions because more vicariant events. Ethiopian Oriental Australasian

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The Six Faunal Regions

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  1. The Six Faunal Regions • Nearctic (us) • Palearctic • More species than Nearctic because larger • Neotropical (most species) • Tropical regions have more species than temperate regions • More species than other tropical regions because more vicariant events

  2. Ethiopian • Oriental • Australasian • Includes New Guinea • Lots of species for a small area

  3. Distributions can be explained by Connections that enabled spread beyond current Barriers Vicariant events involving orders and families of birds

  4. The Earth Just Prior To Archaeopteryx (150 MYA): Pangea Breaks Apart Source: http://www.odsn.de/odsn/services/paleomap/animation.html

  5. No Worldwide Pangea Connection For Modern Birds May have affected birds of the Cretaceous (two lines)

  6. Southern Connection (Gondwanaland, 65 MYA) • Connects old lineages • Explains relatedness of forms on southern continents: Neotropical, Ethiopian, Australasian • Family, Order level

  7. Lineages Distributed Among Southern Continents • Ratites • Ostriches Ethiopian (spread to Palearctic), elephant birds Ethiopian (Madagascar), emus and cassowaries Australasian, kiwis and moas Australasian (New Zealand), rheas and tinamous Neotropical • All flightless, require vicariant event to spread • Penguins

  8. Lineages That Spread Worldwide Through Additional Connections • Parrots • Pigeons • Pheasants and quail • Cuckoos

  9. Genetic Relationships of Worldwide Forms • Neotropical forms are related to Australasian (parrots) or Ethiopian (quail) forms, not Nearctic forms • Origin of Nearctic forms is Ethiopian to Palearctic to Nearctic (via Greenland connection)

  10. Greenland Connection (65 MYA) • Tropical connection • Forms shifted south in cooler periods • Explains relatedness of forms in tropical regions – Neotropical, Ethiopian, Oriental • Family level • Examples: Trogons, barbets

  11. Bering Connection (Current) • Connects cold-adapted forms of tundra, boreal forest • Many close relationships between northern forms of Nearctic, Palearctic • Species (tundra), Genus (boreal forest) level

  12. Convergence Among Temperate Forms of Nearctic, Palearctic • Connections apply to tropical (Greenland) or cold-adapted (Bering) forms, not temperate forms • Radiation of passerines occurred after Greenland connection, has never been connection for temperate passerines • Unrelated forms fill same ecological niche in two regions

  13. Panama Connection (6 MYA) • Recent connection between Nearctic, Neotropical regions • Many endemic Neotropical forms due to long isolation (65 MYA – 6 MYA) • Movement of forms both ways, forms warmer Nearctic similar Neotropical • Genus level

  14. Convergence of tropical forms between Neotropical and Ethiopian / Oriental regions • Jacamars and Bee-eaters • Toucans and Hornbills • Hummingbirds and Sunbirds

  15. Connections Between Ethiopian, Oriental and Palearctic Regions • Himalayan: Oriental – Palearctic • Saharan: Ethiopian – Palearctic • Arabian: Ethiopian - Oriental

  16. Connections in recent past, current barriers only moderately effective • Genus level, forms in drier habitats especially similar • Avifauna three regions essentially the same • No endemics in India due to timing of isolation (150 MYA – 45 MYA)

  17. Borneo Connection • Connects Oriental, Australasian last 15 MY • Very weak connection (Wallace’s line) • Limited one-way movement Oriental forms into Australasia (monarch flycatchers) • Many Australasia endemics due to isolation since southern connection (50 MYA – 15 MYA), especially passerines

  18. Worldwide Distributions • Some families have worldwide distributions because of dispersal abilities, have spread beyond barriers without vicariant events (spread by dispersal events) • True for most waterbirds (gulls, shorebirds, seabirds, rails, herons, ducks), more mobile landbirds (hawks, owls, swallows, swifts)

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