Marsupialia) -- Orders Monotremata Through Peramelina

Main Points 1) Mammalian Characteristics (continued from last Wednesday)

2) Diversity, Phylogeny, and Systematics -- Subclasses Prototheria and Theria -- Infraclass Metatheria (Marsupialia) -- Orders Monotremata through Peramelina

3) Modern distributions of prototherians and metatherians -- adaptive radiations -- example: Wallace’s line and continental vs. oceanic islands

4) Reproductive strategies in dasyuromorphs -- example: the evolution of semelparity

Terms: pinna, Allen’s rule, oviparous, cloaca, altricial, marsupium, adaptive radiation, continental island, oceanic island, monotypic, fossorial, iteroparity, semelparity, syndactyly

Pre-reading: Wednesday 13 Sept = Wong 2002 Monday 18 Sept = Sykes et al 2014, Macleod 2014 1 Adaptive coloration

• Cryptic coloration

2 Adaptive Coloration

• Cryptic coloration

3 Some external characteristics of mammals

1) hair

2) pinna (plural: pinnae)

4 Some external characteristics of mammals

• Allen’s rule

5 Zoogeographic Regions

6 Subclass Prototheria

7 Subclass Prototheria

8 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

9 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

10 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

11 Discoveries of New Mammals

Attenborough’s long-beaked echidna

12 Subclass Theria, Infraclass Metatheria

13 Subclass Theria, Infraclass Metatheria

Taxonomy: 7 orders

Distribution: 4 orders Australasian, 3 orders Neotropical

14 Wallace’s Line

15 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?

16 Late Jurassic, ~150 MYA

17 Subclass Theria, Infraclass Metatheria sugar glider flying squirrel red kangaroo white-tailed deer

black-tailed jackrabbit rabbit-eared fishing cat bandicoot marsupial “cat”

18 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

19 Order Didelphimorphia: opossums

Taxonomy: 63 species

Distribution: Neotropical, 1 species Nearctic

Characteristics: -- most generalized metatherians -- clawless hallux (big toe) -- prehensile tail

20 Order Paucituberculata: shrew opossums

Taxonomy: 6 species

Distribution: Neotropical (Andes mountains)

Characteristics: -- no marsupium -- convergent with shrews

21 Order Microbiotheria: monito del monte

Taxonomy: 1 species (i.e., monotypic order)

Distribution: Neotropical (Andes mountains)

Characteristics: -- genetically similar to Australian metatherians -- hibernates

22 Order Notoryctemorphia: marsupial “mole”

Taxonomy: 1 species (monotypic order)

Distribution: Australasian

Characteristics: -- no pinnae -- eyes vestigal, ears reduced -- enlarged claws -- convergent with other fossorial mammals

23 Order Dasyuromorphia: marsupial “carnivores”

Taxonomy: 2 (or 3?) extant families, 61 (or 62?) species

Distribution: Australasian

Antechinus spp. Tasmanian devil numbat

24 25 Order Dasyuromorphia: marsupial “carnivores”

Taxonomy: 2 (or 3?) extant families, 61 (or 62?) species

Distribution: Australasian

Characteristics: -- well-developed canines -- derived dental formulae (42-46 teeth) -- marsupium usually absent

Evolution of semelparity

breeding survival breeding

0.2 0.2 0.4 0.6 0.8 1.0 prob.post

0 2 4 6 8

annual fecundity (# of kids per litter)

27 Evolution of semelparity

typical

metatherian

breeding survival breeding

0.2 0.2 0.4 0.6 0.8 1.0 prob.post

0 2 4 6 8

annual fecundity (# of kids per litter)

28 Evolution of Semelparity

Antechinus spp.

typical

metatherian

breeding survival breeding

0.2 0.2 0.4 0.6 0.8 1.0 prob.post

0 2 4 6 8 0 2 4 6 8

annual fecundity (# of kids per litter)

29 Order Diprotodontia: kangaroos, wallabies, phalangers, possums, wombats

spotted cuscus Taxonomy: 117 species

Distribution: Australasian

hairy-nosed wombat koala red kangaroo

30 Order Diprotodontia: kangaroos, wallabies, phalangers, possums, wombats

Taxonomy: 117 species

Distribution: Australasian

Characteristics: --diprotodont teeth --syndactyly

31 Order Peramelina (Peremelimorphia): bandicoots

Taxonomy: 21 species

Distribution: Australasian

rabbit-eared bandicoot Eastern barred bandicoot

32 Order Peramelina (Peremelimorphia): bandicoots

Taxonomy: 21 species

Distribution: Australasian

Characteristics: -- hind limbs specialized for hopping -- have placenta, in addition to marsupium rabbit-eared bandicoot Eastern barred bandicoot