• I. Order Montremata
• II. Marsupials

Noneutherian mammals: monotremes and marsupials

Phylogenetically isolated from other mammals

Unique reproductive patterns

I. Monotremata

1. General characteristics of the order
   1. Morphologically unique
   2. Have many reptilian characteristics
   3. Birdlike skull with elongated rostrum
   4. No teeth - Chew food with the tongue and bony plate at roof of mouth (echidna) or roughened gums (platypus)
   5. Pectoral girdle splayed as in reptiles
   6. Pelvic girdle mammal-like
   7. Epipubic bones that come up from the pelvis along the ventral surface

2. Reproduction
   1. Lay eggs
   2. Incubate them like birds
   3. Have mammary glands and make milk
   4. No nipples
   5. Milk is secreted onto the abdominal fur (platypus) or into a temporary pouch and licked off the skin (echidna)
   6. Long periods of maternal care
   7. 1 offspring/year

3. Echidna
   1. Morphology
      1. Round, fat body
      2. Short, thick spines covering body
      3. Tube-like rostrum covered with leathery skin
      4. Long tongue coated with mucous
      5. "Digging" limbs (short, powerful, claws)
      6. Small eyes
      7. Females have a temporary pouch for carrying eggs and babies; structure may be supported by epipubic bones
   2. Ecology and behavior
      1. Solitary
      2. Crepuscular
      3. Live in burrows
      4. Poor eyesight but great sense of smell
      5. Avoid predators by

         1) Digging down

         2) Passively by rolling into a ball and exposing spines

      6. Australian sp. eats ants and termites; New Guinea sp. eats earthworms
      7. Become torpid in cold temperature/low food availability
   3. Reproduction
      1. Lay (usually) 1 egg that hatches in 9 days
      2. After hatching it lives in its mother's pouch for 12 weeks
      3. Spines at 8 weeks
      4. At 12 weeks eyes open and baby leaves pouch for burrow
      5. Weaned at 20 weeks

4. Platypus
   1. General characteristics
      1. Small (0.5-2 kg (<5 lbs))
      2. Adapted to aquatic life

         1) Dense fur
         2) No pinnae
         3) Eyes and ears lie in folds of skin and are covered when underwater
         4) Sphincter muscle closes off nares
         5) Webbed feet

      3. Claws for digging (web extends past claw)
      4. Ankle spurs contain venom
         Also present on male echidnas, but unknown whether they are venomous
      5. Duck-like rostrum covered with moist leathery skin; contains electroreceptors on its front edge
         another view of a platypus bill
   2. Ecology and behavior
      1. Aquatic (streams, ponds)
      2. Crepuscular
      3. Bottom feeder
      4. Eats aquatic crustaceans, insect larvae, earthworms
      5. Forages using electroreception
      6. Shows torpor
      7. Male and female burrows close together or shared
   3. Reproduction
      1. Lays 1 or 2 eggs in a burrow nest
      2. Incubates 12 days then hatches
      3. Hair at 7 weeks, eyes open at 9 weeks, suckled for 16 weeks

II. Marsupials

1. Origins
2. General characteristics:
   1. 50% have pouches (marsupia) form of pouch varies with ecology: kangaroo-opens up top; bandicoot (diggers)- opens on bottom
   2. Epipubic bones (both sexes; whether or not they have pouches)
   3. Uterus and vagina are biphid
   4. Penis is also biphid
   5. Teeth
      1. Different numbers of incisors on top and bottom
      2. P 3/3, M 4/4
   6. Brains are relatively small and not very convoluted

3. Reproduction
   1. Highly altricial young
   2. Short gestation (8-43 days)
   3. Young born extremely small relative to adult size

   Dasyurus (quoll)	infant 1/4,250 of adult size
   kangaroo	infant 1/33,400 of adult size

   4. Organs not completely developed
      1. Heart: incomplete separation of the ventricles
      2. Lungs: no alveoli
      3. Naked
      4. Blind

   5. Well-developed front limbs for grasping fur
   6. Move to pouch or (if pouchless) grab ahold of teats
   7. Teat swells in its mouth to make a semi-permanent attachment
   8. Stays in pouch 1 week - 1 year
   9. Leaves pouch at weight roughly equivalent to birthweight of a similarly-sized placental
   10. Milk changes composition during lactation
       1. Early: high protein, low fat (for structural development)
       2. Later: low protein, high fat (for rapid increase in mass)

4. What used to be the "order Marsupialia" is now 7 separate orders

   Phylogeny

   New classifiation system based on incisor teeth and digits.

   • Teeth are either diprotodont ("two front teeth") or polyprotodont ("many front teeth")
   • Digits are either didactylus (separate; ancestral state) or syndactylus ("fused toes")
   
   
   

   
   
   

   1. Order Didelphimorphia

      # of Genera	15
      # of Species	63
      Distribution	South America

      1. Ancestral type for all marsupials
      2. 50 teeth (5/4, 1/1, 3/3, 4/4=50)
      3. Opposable, clawless hallux (for climbing?)
      4. Long prehensile tail
      5. Arboreal
   2. Order Dasyuromorphia

      # of Genera	15
      # of Species	61
      Distribution	Australia

      1. Shrew- to dog-sized
      2. Marsupium absent or poorly developed
      3. Long, furry tail that is never prehensile
      4. Terrestrial
      5. Very diverse

         Small species are shrew-like
         Dasyuroides
         Dasyurus (tiger quoll)
         Thylacinus (Tasmanian wolf, thylacine)

   
   
   
   3. Order Diprotodontia, Family Petauridae

      # of Genera	3
      # of Species	15
      Distribution	Australia

      1. Some species convergent with flying squirrels
      2. Furred membranes between limbs
      3. Arboreal
      4. Nocturnal
      5. Eat fruit, leaves, nuts
   4. Order Diprotodontia, Family Macropodidae

      # of Genera	11
      # of Species	50
      Distribution	Australia
      Common names	kangaroos, wallabies

      1. Range widely in size (0.5 kg to 90 kg)
      2. Ecological equivalents of antelopes and deer
      3. Limbs are highly specialized for cursorial locomotion

         1) Elongated rear limbs
         2) Syndactyly
         3) 4th digit most important; 5th large also

      4. Bipedal
      5. Move by saltation
      6. Tails very large, used for propulsion and support
      7. Large marsupium, opens anteriorly
      8. Teeth

         1) Have a diastema
         2) Molars replaced from the rear (up to 9 of them)

   5. Order Peramelemorphia (bandicoots)

5. Examples of convergence

   Eutherian	Marsupial
   cat	quoll
   Artiodactyl skull	kangaroo skull
   flying squirrel	sugar glider
   mole	marsupial moles (fossorial, insectivorous, vestigial eyes, no pinnae, robust forelimbs)
   marmot skull	wombat (marmot-like teeth, minimal tail)
   wolf skull	thylacine skull video

6. Diversity
   1. Now is much lower than it once was...
   2. Massive extinctions in Australia that may be the result of colonization by aboriginal humans.
   3. Later, more extinctions when Europeans reached Australia
      1. Competition with domestic livestock
      2. Clearing of habitat for agriculture
      3. Introduction of domestic species (eg. rabbit)
   4. Interesting extinct species:

      Thylacoleo	lion-sized, carnassial pair, retractile claws artist's rendering fossil skeleton
      Diprotodon	rhino-sized; largest marsupial ever known artist's rendering fossil skeleton
      Thylacosmilus	sabre-tooth cat-like marsupial artist's rendering fossil skull