Laurasiatheria is comprised of eight orders:

  1. Cetacea
  2. Artiodactyla
  3. Perissodactyla
  4. Canivora
  5. Pholidota
  6. Chiroptera
  7. Soricomorpha
  8. Erinaceomorpha

In some phylogenies (including Murphy et al. 2001) Soricomorpha and Erinaceomorpha are combined into a single group called Eulipotyphla.

I. Order Cetacea

The fossil record on whale evolution

A. Suborder Mysticeti

Common name baleen whales
# of genera 6
# of species 10
Distribution all the oceans of the world

  1. General characteristics

    1. Largest animals ever known (living or fossil)
    2. Mostly plankton feeders
    3. Populations have been driven near extinction by hunting

  1. Foraging adaptations

    1. Lack teeth as adults
    2. Have plates of baleen
      baleen in a humpback whale

      1. Horny epithelial material in longitudinal strands
        another view of baleen
        Close-up view
      2. 130-400 plates
      3. Telescoped maxilla extends infraorbitally

    1. Methods of feeding

      1. Skimming (eg, right whales)
        video clip of right whale skimming
      2. Gulp-feeding (eg, rorquals: blue whale, humpback whales, fin whales)

        Gulp-feeding in humpback whales is a cooperative behavior:
      3. Bottom-ploughing (eg, grey whale)

  1. Migrations
    Humpback whale
    Gray whale

B. Suborder Odontoceti

Common name toothed whales
# of genera 43
# of species 67
Distribution all oceans and all seas connected to oceans, freshwater rivers and lakes (North and South America, Asia, Africa)

  1. General characteristics

    1. Most diverse suborder of Cetaceans
    2. Asymmetry of cranial bones
    3. Telescoped maxilla extends supraorbitally

  1. Foraging

    1. Many of them are carnivorous
    1. Many more teeth than the typical pattern, OR lost all (or all but one) teeth
    2. Teeth are homodont and cone-shaped

  1. Respiratory canal and food passages are completely separated by specializations in the glottis and larynx

  1. Interesting examples

    1. Sperm whale
    1. Narwal
    1. family Delphinidae
      spotted dolphin
    1. family Platanistidae
      Ganges River dolphin
      Amazon river dolphin

    II. Order Artiodactyla

    1. General characteristics

      1. Two enlarged digits share the weight of the body about equally (paraxonic)
      2. Upper incisors and canines lost or reduced
      3. Antorbital pit in many species
      4. Males (and sometimes females) have weaponry
        1. tusks
        2. antlers
        3. horns
      5. Digestive tract morphology
    1. Suborder Suinae

      1. Suidae
      2. Tayassuidae
      3. Hippopotamidae

    1. Suborder Ruminantia

      1. Camelidae
      2. Cervidae
      3. Giraffidae
      4. Antilocapridae
      5. Bovidae
      6. Moschiidae
        male with tusks
      7. Tragulidae

    III. Order Perissodactyla

    Common names horses, tapirs, rhinos
    # families 3
    # genera 6
    # species 17
    Distribution Africa, Asia, S. America

    1. General characteristics

      1. Unguligrade limbs
      2. Enlarged central digit carries most of body weight (mesaxonic)
      3. Elongated skull
      4. Canine teeth reduced or absent
      5. Complex ridge pattern on cheek teeth
      6. Simple stomachs with large caecum (hind gut fermenters)
    1. Families

      1. Equidae
      2. Rhinocerotidae
      3. Tapiridae

    IV. Order Pholidota

    Common name pangolin
    # of Genera 1
    # of Species 7
    Distribution Africa, S.E. Asia

    1. General characteristics of the order

      1. Name means "scaly ones"
      2. Major diagnostic character is the scales that cover their bodies

        1. Made of keratinized epidermis
        2. Periodically replaced as they wear and fall out
        3. Leaf shaped
        4. Cover top of head, top and sides of body and limbs, and entire tail
        5. Parts without scales are hairy

      3. Arboreal ones have prehensile tails, terrestrial ones have short tails
      4. Long, tubular rostrum
      5. Long sticky tongues (extends all the way back into the chest cavity when retracted)
      6. No teeth
      7. Horny epithelium with "teeth" in the pyloric region for smashing insects
      8. Digging limbs

        1. Plantigrade
        2. 5 digits
        3. Long claws

    1. Ecology and behavior

      1. Insectivorous
      2. Some are terrestrial, some arboreal

      3. Roll into a ball as an antipreditor defense

    V. Order Carnivora

    Comon name dogs, cats, bears
    Families 15
    Genera 126
    Species 287
    Distribution Nearly worldwide
    1. Name means "flesh eater"

    2. Range in size from least weasel (mouse-sized) to Kodiak brown bear (terrestrial; up to 800 kg) and male southern elephant seal (aquatic; 3600 kg)

    3. General characteristics

      1. Teeth

        1. Canine teeth
        2. Carnassial pair (blade-like fourth pre-molar and first molar) (Fig. 15.4)

      1. Sharply defined mandibular fossa, where mandible articulates with cranium (some species)
      2. Long rostrum with complex turbinal bones
      3. Well developed anal glands

    1. Modes of life (terrestrial, semi-aquatic or aquatic)

      1. Terrestrial and semi-aquatic forms

        1. Plantigrade or digitigrade (depending on extent of cursoriality)
        2. Four or five toes to each foot
        3. Long, sharp claws on all digits
        4. fusion of wrist bones

      1. Aquatic forms (pinnipeds)

        1. Limbs enclosed within body up to knees and elbows
        2. Elongated metatarsals and metacarpals, webbing between digits to produce flippers
        3. Large body size
        4. Blubber
        5. Nostrils are slits that must be forced open
        6. Nipples and external genitalia are withdrawn into slits
        7. Most breed and all give birth on land, molt on land
        8. Respiratory system adaptations

    1. Phylogenetic history and selected families

      1. Felidae (cats)

      2. Hyaenidae (hyenas, aardwolf)

      3. Herpestidae and Eupleridae (mongooses, meerkats)

      4. Viverridae (civets)

      5. Canidae (dogs, wolves, foxes, jackals)

      6. Mustelidae (weasels, otters)

      7. Procyonidae (racoons)

      8. Ursidae (bears)

      9. Otariidae (eared seals)

      10. Odobenidae (walrus)

      11. Phocidae (earless seals)

      VI. Order Chiroptera

      A. General characteristics

      1. Forelimbs modified as wings (the only true flying mammals)

        1. Radius (forearm), metacarpals (hand) and phalanges (fingers) #2-#5 greatly elongated
        2. Enclosed in a web ( patagium , 2 layers of skin, muscle, connective tissue)
        3. Claws on pollex and all hind digits
        4. Keel on sternum

      1. Ecology and behavior

        1. Widely varied diets

          1. Insects
          2. Fruit, nectar, pollen
            1) long snout
            2) long tongues
            3) specialized facial and body hairs to trap pollen
            4) pollen is their primary source of protein
          3. Fish and small vertebrates
            1) echolocate on water surface
            2) catches fish with feet
          4. Blood
            1) heat sensing pits in nose leaf
            2) specialized incisors
            3) saliva contains anticoagulant
            4) specialized kidneys

        1. Nocturnal
        2. Gregarious, roost in caves and hollow trees
        3. Hang upside down
          1. Easier to take off? video (at 2:50)
          2. Leg bones too delicate to support body weight?
          3. Hip bones reversed to allow control of uropatagium? video (at 1:00)

        4. Reproductive variants common

        B. Evolution and phylogenetics

        1. Ancestry is murky

          1. Earliest fossil bat Icaronycteris (60 mya) (Fig. 12.10)
          2. Fully formed wings
          3. Skull morphology indicates ability to echolocate

        1. Proposed phylogenies

          1. Superorder Archonta - Based on features of the visual system ("Pettigrew hypothesis", no longer supported)

          2. Superorder Archonta - Based on genetic and morphological data (no longer supported)
          3. Based on more recent genetic data, leading to new proposed suborders (Yinpterochiroptera and Yangochiroptera)

        VII. Order Erinaceomorpha

        Common name hedgehogs
        # of Genera 7
        # of Species 21
        Distribution Africa, Eurasia, Southeast Asia

        1. Mouse- to rabbit-sized
        2. Have spines (short ones) - roll into ball if threatened
        3. Omnivorous (skull)
        4. Temperature regulation is heterothermic
        5. Are capable of hibernation ( obligate in some species)

      VIII. Order Soricomorpha

      1. Talpidae

        Common name moles
        # of Genera 17
        # of Species 42
        Distribution Eurasia, North America

        1. Mouse- or rat-sized
        2. Fossorial
        3. Small eyes, sometimes covered by skin
        4. Long snout
        5. Pinnae reduced or absent
        6. Thick, velvetty fur
        7. Front limbs rotated out to side (digits out) and very robust
        8. Long claws
        9. Keeled sternum
        10. Behavior and ecology

          1) Insectivorous (see skull)
          2) Burrow just under the surface, often leaving ridges
          3) Often considered a pest, but they're really helpful to plant growers because they aerate soil and eat insects that damage plants
        11. Baby star-nosed moles

      1. Solenodontidae

        Common name solenodon
        # of Genera 1
        # of Species 2
        Distribution relict species, only on Cuba and Haiti

        1. Muskrat-sized
        2. Outcompeted by other placentals; no natural predators until domestic dogs and cats
        3. Defensive behavior is to roll in ball but they lack spines...
        4. Submaxillary gland toxin, grooved lower incisors

      1. Soricidae

        Common name shrews
        # of Genera 23
        # of Species 312
        Distribution worldwide except Australia, some of South America and polar regions

        1. Among the smallest of all mammals (2.5-180 grams)
        2. In one subfamily the teeth are pigmented (dark red)
        3. Very high metabolic rate
        4. Ecology and behavior

          1) Terrestrial
          2) Prefer mesic habitat
          3) Solitary, territorial

        1. several species of shrews have venomous saliva

          1) Seems to have effects like a neurotoxin
          2) Venom is produced in and secreted from submaxillary salivary glands near the base of lower incisors
          3) Delivered via grooves in the lower incisors
          4) Probably used to kill prey (mice, frogs)
          5) Shrew delivers bite to nape of neck/base of skull, where venom could rapidly get to central nervous system