Mammalian historical biogeography

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The extant Eutherian lineagesmolecular phylogeny
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Afrotheria
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Xenarthra Pilosa Cingulata
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Historical Biogeography ofearly Eutherian
evolution
Plate tectonics explain the diversification of
the major placental clades
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Pangea
Boreoeutheria
Laurasia
Gondwanaland
Atlantogenata
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Euarchontoglires
Laurasiatheria
Afrotheria
Xenarthra
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Major biogeographic features in the distribution
of Afrotheria and Xenarthra island continents
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Major biogeographic features in the distribution
of Afrotheria and Xenarthra original dispersal
(approx.)
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Major biogeographic features in the distribution
of Afrotheria and Xenarthra recent dispersal
(approx.)
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Afrotheria
Atlantogenata Afrotheria Afrosoricida Macrosce
lidea Tubulidentata Sirenia Hyracoidea Probosc
idea
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Tenrecidae, Chrysochloridae
Atlantogenata Afrotheria Afrosoricida ?
tenrecs, golden moles Macroscelidea Tubulidentat
a Sirenia Hyracoidea Proboscidea
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Tenrecidae on Madagascar
Tenrec historical biogeography - hypotheses
single common ancestor
single common ancestor, back dispersal to Africa
multiple ancestors from different African taxa
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Tenrecidae

• 10 living genera (mostly Madagascar, some
  Africa)
• convergent on hedgehogs, shrews, opposums,
• mice, otters
• endothermic, but heterothermic
• one of the remarkable adaptive
• radiations on Madagascar

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Atlantogenata Afrotheria Afrosoricida Macrosce
lidea ? elephant shrews Tubulidentata Sirenia H
yracoidea Proboscidea
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Macroscelidea

• Elephant shrews
• 4 genera
• saltatorial
• insectivorous/omnivorous

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Atlantogenata Afrotheria Afrosoricida Macrosce
lidea Tubulidentata ? aardvark Sirenia Hyracoid
ea Proboscidea
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Tubulidentata

• Orycteropus aardvark
• myrmecophageous (termites)
• no enamel on cheekteeth

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Atlantogenata Afrotheria Afrosoricida Macrosce
lidea Tubulidentata Sirenia ? manatees,
dugongs Hyracoidea Proboscidea
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Sirenia ? out of Africa
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Sirenia Dugongidae

• Dugongidae
• Dugongs
• Stellar Sea Cow
• Bering Sea
• discovered mid-1700s
• extinct late 1700s

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Sirenia Trichechidae

• Trichechidae
• Manatees
• Threats
• Boats
• Drained/altered lagoons

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Atlantogenata Afrotheria Afrosoricida Macrosce
lidea Tubulidentata Sirenia Hyracoidea ?
hyraxes Proboscidea
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Hyraxes
feet moist, suction cup, glandular, hoove-like
nails
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Hyraxes
lophodont molars
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Atlantogenata Afrotheria Afrosoricida Macrosce
lidea Tubulidentata Sirenia Hyracoidea Probosc
idea ? elephants
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Loxodonta AfricanElaphus Asian
both sexes
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lophodont cheekteeth
Asian
African
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cheekteeth replacement
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elephants
graviportal locomotion limbs pillar-like to
support weight
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phylogeny based on complete mtDNA sequence,
including extinct Wooly mammoth!!
subungulates
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Loxodonta
forest
2 African species
savanna
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Proboscideans through time
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Pleistocene/Holocene Proboscideans
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Pleistocene/Holocene Proboscideans
Dwarf woolly mammoths on Wrangel Island until
about 3,000 years ago
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Pleistocene/Holocene Proboscideans
Columbia mammoths in Las Vegas Valley,
Late Pleistocene
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Xenarthra Pilosa Cingulata
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Xenarthra strange joints
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Xenarthra
Atlantogenata Xenarthra
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Xenarthra biogeography in North America
Atlantogenata Xenarthra
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Atlantogenata Xenarthra armadillos
(Cingulata) sloths and anteaters
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armadillos
Dasypus novemcinctus nine-banded armadillo
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Dasypus novemcinctus nine-banded
armadillo monozygotic polyembryony multiple
embryos from single zygote
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Dasypus novemcinctus nine-banded armadillo range
shifting with climate change
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some extinct armadillos
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Atlantogenata Xenarthra armadillos sloths and
anteaters (Pilosa)
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Pilosa
extant sloths
Bradypus 3-toed sloth
Choloepus 2-toed sloth
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sloth evolution and extinction
Bradypus 3-toed sloth
Choloepus 2-toed sloth
monophyletic??
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sloth evolution and extinctionadding the giant
ground sloths
Choloepus 2-toed sloth
Bradypus 3-toed sloth
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sloth evolution and extinctionthe giant ground
sloths
4 North American genera, Late Pleistocene
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sloth evolution and extinctionthe giant ground
sloths
North American / South American connection
Great American Interchange after Panamanian Land
Bridge formed 3 million years ago
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sloth evolution and extinctionthe giant ground
sloths
Nothrotheriops Shasta Ground Sloth
Diet reconstructed from feces DNA sequences
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anteaters
Tamandua
Cyclopes silky anteater
Myrmecophaga giant anteater
myrmecophagy ant and termite eater
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Xenarthra claws