The superorder Laurasiatheria is comprised of eight orders:

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

Cetacea and Artiodactyla are sister taxa that are sometimes combined into a clade called Cetartiodactyla.

Soricomorpha and Erinaceomorpha are sister taxa that are sometimes combined into a single group called Eulipotyphla.

1. Order Cetacea (whales and dolphins)

The fossil record on whale evolution

1. Suborder Odontoceti (toothed whales)
2. Suborder Mysticeti (baleen whales)
   1. General characteristics
      1. Largest animals ever known (living or fossil)
      2. Feed mostly on plankton and krill
      3. Populations have been driven near extinction by hunting
   2. Foraging adaptations
      • Lack teeth as adults
      • Have plates of baleen
        • Close-up view
        • 130-400 plates arranged in parallel rows
      3. Gulp feeding in humpback whales - a cooperative behavior
         • Gulp-feeding is characteristic of rorquals: blue whale, humpback whales, fin whales)
         • Vocalizations to herd schools of fish
         • Make Bubble nets encircle fish
         • Whales lunge upward through the school of fish and consume them
         • Ventral pleats expand to make room for fish + water, then squish out the water to leave only fish
         • Video

2. Order Artiodactyla

1. General characteristics
   1. Unguligrade limbs
   2. Two enlarged digits share the weight of the body about equally (paraxonic)
   3. Elongated skull
   4. Canine teeth reduced or absent
   5. Complex ridge pattern on cheek teeth
   6. Males (and sometimes females) have weaponry
      1. Tusks - found in pigs (family Suidae), hippos (family Hippopotamidae) and some small deer (family Moschiidae)
      2. Antlers - found in deer (family Cervidae)
      3. Permanent horns - found in cows and antelopes (family Bovidae)
      4. Horns with keratin sheath that is shed annually - found in pronghorn antelope (family Antilocapridae)
   7. Digestive tract morphology
      • Non-ruminants
      • Ruminants

3. Order Perissodactyla (horses, rhinos, tapirs)

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)

4. Order Pholidota (pangolins or scaly anteaters)

General characteristics

1. 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. Roll into a ball as an antipreditor defense
2. Convergence with Pilosa and Tubulidendata (and lumped with them in early phylogenies)
   • Long, tubular rostrum
   • Long sticky tongues (extends all the way back into the chest cavity when retracted)
   • No teeth
   • Roughened epithelium in stomach for smashing insects
   • Digging limbs

     Cute pictures

     • female and infant

5. Order Carnivora (carnivores)

General characteristics

1. Teeth vary with diet
   • Typical carivore dentition consists of well developed Canine teeth and a carnassial pair (blade-like fourth pre-molar and first molar)
   • Species with more omnivorous diets have bunodont molars from crushing food rather than a carnassial pair for slicing flesh, e.g. raccoons, bears
   • Myrmecophagous species have sparse dentition (e.g., aardwolf - upper tooth row of aardwolf)
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; see video at 0:30-0:50)
3. Diversity of lifestyles (terrestrial, semi-aquatic or aquatic)

One cool thing - Spotted hyena females are masculinized

• male or female?
• reproductive anatomy
• video of parturition
• Adaptive significance - read more here if you're interested

6. Order Chiroptera (bats)

General characteristics

1. Forelimbs modified as wings (the only true flying mammals)
2. Radius (forearm), metacarpals (hand) and phalanges (fingers) #2-#5 greatly elongated
3. Enclosed in a web ( patagium , 2 layers of skin, muscle, connective tissue)
4. Claws on pollex and all hind digits

What makes bats so ecologically successful?

1. Ability to fly - can disperse widely
2. Widely varied diets (and specializations)
   • Insects
   • Fruit, nectar, and pollen
     • long snout
     • long tongues
     • specialized facial and body hairs to trap pollen
     • pollen is their primary source of protein
   • Fish and small vertebrates
   • Blood
     • heat sensing pits in nose leaf - locate superficial blood vessels
     • specialized incisors - make a shallow cut
     • saliva contains anticoagulant - keeps blood flowing
     • grooved tongue - speeds up drinking
     • tubular, highly vascularized stomach - expands to fill with blood, water removed from solid blood fraction
     • specialized kidneys - produce dilute urine during blood drinking, concentrated urine back at the roost
   
   
   
3. Nocturnal activity - reduces competition with other insectivores
4. Reproductive variants common (e.g., delayed fertilization, delayed implantation, delayed development) - allows success in a variety of otherwise inhospitable environments
5. Facultative homeothermy
   • Hibernation
   • Diheterothermy

7. Order Erinaceomorpha (hedgehogs)

General characteristics

• Mouse- to rabbit-sized
• Have spines (short ones) - roll into ball if threatened
• Omnivorous (skull)

8. Order Soricomorpha (shrews and moles)

General characteristics

• Have a large number of ancestral traits (small size, diet, dentition, plantigrade limbs, single type of hair)
• Among the smallest of all mammals (2.5-180 grams)
• Very high metabolic rate - leads to ultradian activity rhythms

One cool thing - Several species of shrews have venomous saliva!

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