lecture 2 - Jake Goheen

Main Points
1) Mammalian Characteristics:
Diversity, Phylogeny, and Systematics
-- Subclasses Prototheria and Theria
-- Infraclass Metatheria (Marsupialia)
-- Orders Monotremata through Peramelina
2) Modern distributions of prototherians and metatherians
-- adaptive radiations
-- example: Wallace’s line and continental vs. oceanic islands
3) Reproductive strategies in dasyuromorphs
-- example: the evolution of semelparity
4) Terms: sister group, oviparous, cloaca, altricial, marsupium,
adaptive radiation, continental island, oceanic island, monotypic,
fossorial, iteroparity, semelparity, syndactyly
Pre-reading: Monday 14 Sept = Wong 2002
Wednesday 16 Sept = Sykes et al 2014, Macleod 2014
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Zoogeographic Regions
2
Subclass Prototheria
3
Subclass Prototheria
4
Subclass Prototheria, Order Monotremata
Taxonomy: 5 species, 2 families
Distribution: Australasian, in coastal, southeastern
Australia and in New Guinea (echidnas only)
long-nosed echidna
short-nosed echidna
duck-billed platypus
5
Subclass Prototheria, Order Monotremata
Taxonomy: 5 species, 2 families
Distribution: Australasian, in coastal, southeastern
Australia and in New Guinea (echidnas only)
Diagnostic characters:
1) oviparous
2) mammary glands
lacking nipples
3) no pinnae
6
Subclass Prototheria, Order Monotremata
Taxonomy: 5 species, 2 families
Distribution: Australasian, in coastal, southeastern
Australia and in New Guinea (echidnas only)
Diagnostic characters:
4) cloaca
5) no teeth in adults
6) electroreceptors in snouts
7
Discoveries of New Mammals
Attenborough’s long-beaked
echidna
8
Subclass Theria, Infraclass Metatheria
9
Subclass Theria, Infraclass Metatheria
Taxonomy: 7 orders
Distribution: 4 orders Australasian, 3 orders Neotropical
10
Wallace’s Line
11
Discussion questions: which types of islands
would you expect to have mammals more
similar to the mainland? Which types of
mammals would you most expect to see on
islands?
12
Late Jurassic, ~150 MYA
13
Subclass Theria, Infraclass Metatheria
sugar glider
flying squirrel
red kangaroo
white-tailed deer
black-tailed
jackrabbit
rabbit-eared
bandicoot
marsupial “cat”
fishing cat
14
Subclass Theria, Infraclass Metatheria
Taxonomy: 7 orders
Distribution: 4 orders Australasian, 3 orders Neotropical
Diagnostic characters:
1) dental formula = 5/4, 1/1, 3/3, 4/4 = 50 teeth
2) brain and braincase are relatively small
3) young are born altricial, and are carried in marsupium
4) cloaca
5) scrotum anterior to penis
15
Order Didelphimorphia: opossums
Taxonomy: 1 family, 15 genera, 63 species
Distribution: Neotropical, 1 species Nearctic
Characteristics:
-- most generalized metatherians
-- clawless hallux (big toe)
-- prehensile tail
16
Order Paucituberculata: shrew opossums
Taxonomy: 1 family, 3 genera, 6 species
Distribution: Neotropical (Andes mountains)
Characteristics:
-- no marsupium
-- convergent with shrews
17
Order Microbiotheria: monito del monte
Taxonomy: 1 family, 1 genus, 1 species
(monotypic order)
Distribution: Neotropical (Andes mountains)
Characteristics:
-- genetically similar to Australian metatherians
-- hibernates
18
Order Notoryctemorphia: marsupial “mole”
Taxonomy: 1 family, 1 genus, 1 species
(monotypic order)
Distribution: Australasian
Characteristics:
-- no pinnae
-- eyes vestigal, ears reduced
-- enlarged claws
-- convergent with other
fossorial mammals
19
Order Dasyuromorphia: marsupial “carnivores”
Taxonomy: 2 (or 3?) extant families, 15 genera,
61 species
Distribution: Australasian
Antechinus spp.
Tasmanian devil
numbat
20
21
Order Dasyuromorphia: marsupial “carnivores”
Taxonomy: 2 (or 3?) extant families, 15 genera,
61 species
Distribution: Australasian
Characteristics:
-- well-developed canines
-- derived dental formulae (42-46 teeth)
-- marsupium usually absent
22
1.0
0.8
0.6
0.4
0.2
prob. post-breeding survival
Evolution of Semelparity
0
2
4
6
8
annual fecundity (# of kids per litter)
23
1.0
0.8
0.6
0.4
typical
metatherian
0.2
prob. post-breeding survival
Evolution of Semelparity
0
2
4
6
8
annual fecundity (# of kids per litter)
24
1.0
0.6
0.8
Antechinus spp.
0.4
typical
metatherian
0.2
prob. post-breeding survival
Evolution of Semelparity
0
2
4
6
8
0
2
4
6
8
annual fecundity (# of kids per litter)
25
year 1
constant
prob survival
year 2
mean # kids prob survival
year 2
mean # kids
1
0.8
0.8
0.64
0.64
2
0.75
1.5
0.56
1.13
4
0.6
2.4
0.36
1.44
6
0.2
1.2
0.04
0.24
8
0
0
0
0
0.8
1.0
# kids per
litter
year 1
0.2
0.4
0.6
typical
metatherian
26
0
2
4
6
8
year 1
constant
prob survival
year 2
mean # kids prob survival
year 2
mean # kids
1
0.8
0.8
0.64
0.64
2
0.75
1.5
0.56
1.13
4
0.6
2.4
0.36
1.44
6
0.2
1.2
0.04
0.24
8
0
0
0
0
0.8
1.0
# kids per
litter
year 1
0.2
0.4
0.6
typical
metatherian
27
0
2
4
6
8
year 1
constant
prob survival
year 2
mean # kids prob survival
year 2
mean # kids
1
0.8
0.8
0.64
0.64
2
0.75
1.5
0.56
1.13
4
0.6
2.4
0.36
1.44
6
0.2
1.2
0.04
0.24
8
0
0
0
0
0.8
1.0
# kids per
litter
year 1
0.2
0.4
0.6
typical
metatherian
28
0
2
4
6
8
estimated lifetime fecundity
12
10
typical
metatherian
8
6
Antechinus spp.
4
2
0
0
2
4
6
8
annual fecundity
29
1.0
0.6
0.8
Antechinus spp.
0.4
typical
metatherian
0.2
prob. post-breeding survival
Evolution of Semelparity
0
2
4
6
8
0
2
4
6
8
annual fecundity
30
Order Diprotodontia: kangaroos, wallabies,
phalangers, possums, wombats
Taxonomy: 10 families, 117 species
spotted cuscus
Distribution: Australasian
hairy-nosed wombat
koala
red kangaroo
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Order Diprotodontia: kangaroos, wallabies,
phalangers, possums, wombats
Taxonomy: 10 families, 117 species
Distribution: Australasian
Characteristics:
--diprotodont teeth
--syndactyly
32
Order Peramelina (Peremelimorphia): bandicoots
Taxonomy: 2 families, 21 species
Distribution: Australasian
rabbit-eared bandicoot
Eastern barred bandicoot
33
Order Peramelina (Peremelimorphia): bandicoots
Taxonomy: 2 families, 21 species
Distribution: Australasian
Characteristics:
-- hind limbs specialized for hopping
-- have placenta, in addition to marsupium
34