One opening cloaca

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Subclass Prototheria Order Monotremata

• One opening ? cloaca
• Taxonomy ? Two families
• Family Tachyglossidae (Two species)
• Family Ornithorhynchidae (one species)
• Distribution
• Tachyglossidae ? New guinea, Australia, Tasmania
• Duck-billed platypus ? Eastern Australia and
  Tasmania

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Monotremata General morphology

• Birdlike skull with elongated rostrum
• Electroreceptors
• Toothless in adults
• No auditory bullae
• Appendicular skeleton ? example of mosaic
  evolution
• Different parts evolving at different rates
• Shoulder girdle ? similar to therapsid ancestors
• Pelvic girdle mammal like arrangement
• Reproduction unique among mammals
• Oviparous
• Females have two ovaries (only left one
  functional in platypus)
• Low reproductive rate ? one clutch per year
• Mammalian characteristics
• Have hair
• 4-chambered heart
• Single dentary bone
• Homeothermic

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Monotremata Ornithorhynchidae (Ornithorhynchus
anatinus)
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Monotremata Tachyglossidae
Zaglossus bruijni (long-beaked)
Tachyglossus aculeatus (short-beaked)
Distribution Forested highlands of New Guinea
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Subclass Theria Infraclass Metatheria

• Traditionally known as the Marsupials
• Functional counterparts to eutherians
• Taxonomy
• Once a single order ? Marsupialia
• 272 species subdivided into seven orders
• Distribution? restricted to two strongholds
• Australian region
• Neotropics

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Infraclass Metatheria General morphology

• Skull
• Small, narrow braincase
• Ossified auditory bullae
• Palate ? characteristically large vacuities
• Angular process inflected medially
• Dentition ? Numbers of upper and lower incisors
  always differ
• Highly specialize feet associated with
  specialized modes of locomotion

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Infraclass Metatheria Reproduction

• Presence of marsupium ? varies greatly
• Female tract bifurcated
• Two lateral vaginae on either side of medial
  vagina
• Uterus is duplex
• Male has bifid penis situated posterior to
  scrotum
• Intrauterine gestation period short ? 8 to 43
  days

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Didelphimorphia Didelphidae
1) 15 genera with 63 species 2) Distribution SE
Canada to Southern Argentina 3) Only one species
in N.A. ? Virginia opposum (Didelphis
virginianus)
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Paucituberculata Caenolestidae
Shrew-opossum
1) 3 genera comprising 6 species 2) Disjunct
distributions occupying forested areas of
Andes 3) No Marsupium
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Microbiotheria Microbiotheriidae
Monito del monte (Dromiciops gliroides)
1) Monotypic ? 1 representative 2) Inhabits cool,
southern Andean forests 3) Arboreal and nocturnal
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Dasyuromorphia Myrmecobiidae
1) Monotypic 2) Myrmecophagy Diet of ants and
termites Evolved multiple times in mammals 3) No
marsupium
Numbat (Myrmecobius fasciatus)
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Dasyuromorphia Thylacinidae
1) Recently extinct 2) Dog-sized thylacine or
Tasmanian wolf 3) Once distributed throughout
Australia, New Guinea, and Tasmania
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Dasyuromorphia Dasyuridae (Marsupial mice)
Eastern quoll (Dasyurus viverrinus)
1) 15 genera and 61 species 2) Range from
Australia, New Guinea, Tasmania and few
surrounding islands 3) Occupy a wide range of
habitats ? some are arboreal 4) Largest member ?
Tasmanian devil (Sarcophilus laniarius) a) Once
widespread over Australia b) Now restricted to
Tasmania
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Dasyuromorphia Dasyuridae (Marsupial mice)
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Peramelemorphia Peramelidae (Bandicoots and
bilbies)
1) 3 genera and 8 extant species 2) Trend toward
specialization of hindlimb for running
(Cursorial) or hopping 3) Marsupium present and
opens posteriorly 4) Distributed from Australia,
Tasmania, and New Guinea 5) Terretrial
insectivores and omnivores
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Peramelemorphia Peroryctidae (Spiny bandicoots)
1) 4 genera with 11 species 2) Probably
originated and radiated in New Guinea 3)
Nocturnal, terrestrial, and solitary
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Diprotodontia Phascolarctidae
1) Highly specialized herbivore ? eucalyptus
trees 2) Sedentary ? similar to another
specialized herbivore (sloth) 3) Restricted to
wooded areas in eastern Australia 4) Solitary
Phascolarctos cinereus
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Diprotodontia Vombatidae
1) 2 genera with 3 species 2) Powerful burrowers
? warrens 3) Restricted ranges in Australia and
Tasmania ? Northern hairy nosed wombat is
critically endangered
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Diprotodontia Phalangeridae
1) 6 genera and 18 species 2) Omnivorous 3)
Arboreal ? prehensile tail 4) Distribution
Australia, New Guinea, and surrounding islands ?
scrub or heavily forested areas 5) Several
species are endangered
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Diprotodontia Potoroidae
Musky rat-kangaroo (Hypsiprymnodon moschatus)
Brush-tailed bettong (Bettongia penicillata)
1) Four genera and seven species 2) Unusual diet
- of mushrooms, roots, and insects 3) Weakly
prehensile tail 4) Distribution wet forests
(Potoroos) to arid regions (bettongs) of
Australia 3) Many are endangered
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Diprotodontia Macropodidae
1) 11 genera and 54 species 2) Ecological
equivalents of ungulates 3) New Guinea, Bismark
archipelago, Australia and islands near New
Guinea and New Zealand (By introduction) 4) Vary
greatly in size and structure 5) Dentition
similar to other ungulates a) Lower incisors
project forward b) Have upper incisors 6) Highly
specialized for jumping (saltatorial) b)
Hindlimbs are elongate ? 4th and 5th digit large
others reduced c) Bipedal hopping ? only
large-bodied mammal to do this 7) Tail long and
robust ? used as a balancing organ
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Diprotodontia Macropodidae
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Diprotodontia Burramyidae (Pygmy possums)
1) Thought extinct until 1966 ? now found in
other localities 2) 2 genera and 5 species 3)
Tiny ? 120 to 295 mm (12 to 30 cm or 5 to 12
in) 4) Highly arboreal with a prehensile tail 5)
Restricted to wooded areas 6) Insectivorous/omnivo
rous
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Diprotodontia Acrobatidae
Feathertail glider (Acrobates pygmaeus) ?
Australia
1) Characterized by rows or long, stiff hairs
along either side of tail 2) Both are primarily
nectivorous ? brush-tipped tongues similar to
Burramyids 3) Feathertail glider is smallest
gliding mammal (10 to 14 g)
Feathertail possum (Distoechurus pennatus) ? New
Guinea
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Diprotodontia Petauridae
1) Tail long, bushy and prehensile 2) All species
have a dark dorsal stripe running from head to
tail 3) Nocturnal, arboreal creatures 4) Feed
primarily on sap and nectar 5) Gliders remarkably
similar to NA flying squirrels 6) Three genera
with 10 species 7) Distribution Forested areas
of Australia, New Guinea, and Surrounding islands
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Diprotodontia Pseudocheiridae (ringtail possums
and greater glider)
1) Closely related to Petauridae 2) 5 genera and
14 species 3) Arboreal and nocturnal ? strongly
prehensile tail 4) Herbivorous ? primarily on
leaves 5) Distribution same as Petauridae
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Diprotodontia Tarsipedidae (Honey possum)
1) Monotypic ? Tarsipes rostratus 2) Highly
specialized ? Obligate nectar feeders b) Long,
slender snout d) Cheek teeth small and
degenerate e) Tongue modified for gleaning
nectar 3) Small ? 7 to 12 grams (large shrew
size) 4) Nocturnal and highly arboreal 5)
Distribution Shrubs and woodlands of SW Australia
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Notoryctemorphia Notoryctidae
1) Single species of marsupial mole 2) Inhabits
sandy soils in arid regions of NW and
south central Australia 3) Numerous adaptations
for fossorial life (burrowing) a) Nonfunctional,
vestigial eyes b) 5 posterior cervical vertebrae
are fused c) Forelimbs are robust d) Claws of
3rd and 4th digit are enlarged 4) Marsupium
present ? openings posteriorly
Notoryctes typhlops