Mammals - Part 3

Taxonomy of Mammals

Overview of Mammalian Orders

  • Mammals are classified into three primary subclasses:
    • Prototheria: Egg-laying mammals.
    • Metatheria: Marsupials that carry young in pouches.
    • Eutheria: Placental mammals.

Prototheria

  • Contains all egg-laying mammals.
  • Two extant orders:
    • Ornithorhynchidae: Platypus, found only in Australia.
    • Tachyglossidae: Echidnas, with 4 species found in Australia and Indonesia.
  • Key characteristics:
    • Lay eggs instead of giving birth to live young.

Metatheria

  • Encompasses all marsupials.
  • Common traits:
    • Prehensile tail.
    • Carry young in a pouch.
    • Differential dentition compared to placental mammals.
  • Divided into two superorders:
    • Ameridelphia: Marsupials primarily in the Americas.
    • Families include:
      • Opossums (most in Central/South America, 1 species in North America).
      • Shrew/rat opossums in Central America.
      • Monito del Monte: a single species originating in North America.
    • Australidelphia: Marsupials found mainly in Australia.
    • Includes orders like:
      • Diprotodontia: diverse group (e.g., kangaroos).
      • Peramelemorphia: Bandicoots and bilbies.
      • Dasyuromorpha: Includes Tasmanian devil and marsupial mice.

Eutheria

  • The most diverse group of mammals, both extinct and extant.
  • Comprised of two major groups:
    • Atlantogeneta: Group with southern ancestry.
    • Boreoeutheria: Group with northern ancestry.
  • Atlantogeneta includes two clades:
    • Afrotheria: Animals found in Africa and Madagascar (e.g., elephants, aardvarks).
    • Xenarthra: South American organisms including sloths and armadillos.
  • Boreoeutheria further divided into:
    • Euarchontoglires: Includes rodents and primates.
    • Laurasiatheria: Includes ungulates (even-toed and odd-toed), carnivores (cats and dogs), and bats.

Major Orders Under Boreoeutheria

Glires
  • Comprises rodents and lagomorphs.
  • Order Rodentia is the most diverse, with over 1440 species.
  • Order Lagomorpha includes rabbits, hares, and pikas.
Euarchonta
  • Includes Scandentia (tree shrews), Dermoptera (flying lemurs), and Primates.
  • Primates found globally, except for Antarctica.
Laurasiatheria
  • Major division including Eulipotyphla (insectivores) and Chiroptera (bats).
Artidactyla
  • Even-toed ungulates (e.g., pigs, hippos, camels, and deer).
Perissodactyla
  • Odd-toed ungulates (e.g., horses, rhinos, tapirs).
Carnivora
  • Divided into two suborders:
    • Caniformia (dog-like carnivores).
    • Includes dogs, bears, seals, etc.
    • Feliformia (cat-like carnivores).
    • Includes cats, hyenas, and mongooses.
Pholidota
  • Contains pangolins, known for their scaly skin made of keratin.
  • Regarded as the most trafficked mammal.

Manitoba Diversity

  • Home to nearly 100 species of mammals spread across 25 different families.

  • Important ecological roles, many considered foundational species.

  • Examples:

    • Minke Whale (Balaenoptera acutorostrata)
    • American Ermine (Mustela richardsonii)
    • 13-lined Ground Squirrel (Ictidomys tridecemlineatus)
    • Eastern Red Bat (Lasirus borealis)

Summary

  • Understanding the taxonomy of mammals is essential for studying their diversity, evolution, and ecological significance. This classification helps illustrate the evolutionary relationships among different mammalian species.