Modern Mammals 2

Created by: ValentineDevil
Created on: 11-04-19 10:07

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Modern Mammals
- Dermoptera (Colugos)
  - Two species
  - Kite-shaped membrane that spreads along the side of body between very long legs
- Scandentia
  - Problem phylogenetically
  - 'primate-like' features
    - Relatively large cranium
    - Permanent scrotum
    - Orbits are completely encircled by bone
    - Virtually lack all main defining primate features
    - Shrew-like dentition & elongated thin skull
- Primates
  - Shared derived features
    - Locomotion
      - Grasping hands & opposable thumbs and toes
      - Hallux bearing nail, nails on digits (may be lost)
      - Elongation of the heel bone
      - Hindlimb dominance and shift of centre of gravity
    - Brain and vision
      - Stereoscopic vision
      - Enlargement of orbital cavity
      - Increased brain size (especially foetal size: mass ratio)
    - Reproduction
      - Scrotal testes
      - Long gestation and low litter size
      - Late sexual maturity
      - Many have long lifespans compared to body size
  - Types
    - Strepsirrhini (suborder)
      - Lemurs
      - Lorises & galagos
    - Haplorrhini
      - Tarsiers
    - Platyrrhini (suborder- New World Monkeys)
      - Prehensile tail for arboreal living
    - Catarrhini (suborder- Old World Monkeys)
      - Diverse habitats (dry vs forest)
      - Some prehensile tails
      - Some arboreal, some truly terrestrial
      - Sexual diamorphism more prominent (size, colouration)
      - Old World monkeys and apes
- Rodentia and Lagomorpha
  - Lagomorpha
    - Pikas and rabbits
    - 2 pairs of upper incisors
    - Second pair of peg-like incisors
    - Specialised gut for digesting cellulose
    - Tail quite short
  - Rodentia
    - One pair of elongated incisors and constantly growing
    - Large space between incisors and cheek teeth
    - 3 clades
    - Appox. 42% of all mammals are rodents
    - Rapid radiations (linked to fast lifecycle)
    - Worldwide distribution, many ecological adaptation to fossorial, arboreal and terrestrial
    - Convergent evolution for many ecotypes
- Euliptoyphyla
  - Used to be insectivores and often considered as protoypic Eutherian mammals
  - Moles, moon rates (hedgehogs)
  - Primitive forms of echolocation
  - Ancestral dentition similar to early mammals
  - Specialisations include primitive echolocation and toxic saliva
- Chiroptera
  - Yinpterochiroptera
    - Includes Megachiroptera
      - Most do not echolate and search for fruit by sight (2 species use the tongue to echolate)
  - Yangochiroptera
    - Most others (13 families)
  - Microchiroptera
    - All other bats echolocate using larynx.
      - Call through mouth or in some those with nose leaves, they go through nostrils
  - Characteristics
    - 1200 species
    - Cosmopolitan apart from arctic regions
    - Range of diets
- Cetartiodactyla
  - Paraxonic feet (plane of symmetry between 3 and 4 digits)
  - Talus (ankle bone) double pulley system as a way to conserve energy over long distance movement
  - Reduced or absent canines or incisors
    - Except CWD & muntjac
  - Nasal bones not expanded backwards
- Cetaceans
  - Almost hairless, sebaceous glands absent
  - Rostrum elongated, external pinnae lost
  - Clavicle absent, wrist and elbow joints are immobile- for paddling
- Odd-toed ungulates
  - Mesaxonic feet
- Hindgut fermenters
  - Including Perissodactyla
    - Mainly grazers: relatively few species remain globally. Used to be more biodiverse
- Foregut fermenters
  - Including ruminant Artiodactyla
Carnivora
- Caniformia: Dog-like
  - Generally more omnivorous
- Feliformia: Cat-like
- Modern Mammals
  - Dermoptera (Colugos)
    - Two species
    - Kite-shaped membrane that spreads along the side of body between very long legs
  - Scandentia
    - Problem phylogenetically
    - 'primate-like' features
      - Relatively large cranium
      - Permanent scrotum
      - Orbits are completely encircled by bone
      - Virtually lack all main defining primate features
      - Shrew-like dentition & elongated thin skull
  - Primates
    - Shared derived features
      - Locomotion
        Grasping hands & opposable thumbs and toes
        
        Hallux bearing nail, nails on digits (may be lost)
        
        Elongation of the heel bone
        
        Hindlimb dominance and shift of centre of gravity
      - Brain and vision
        Stereoscopic vision
        
        Enlargement of orbital cavity
        
        Increased brain size (especially foetal size: mass ratio)
      - Reproduction
        Scrotal testes
        
        Long gestation and low litter size
        
        Late sexual maturity
        
        Many have long lifespans compared to body size
    - Types
      - Strepsirrhini (suborder)
        Lemurs
        
        Lorises & galagos
      - Haplorrhini
        Tarsiers
      - Platyrrhini (suborder- New World Monkeys)
        Prehensile tail for arboreal living
      - Catarrhini (suborder- Old World Monkeys)
        Diverse habitats (dry vs forest)
        
        Some prehensile tails
        
        Some arboreal, some truly terrestrial
        
        Sexual diamorphism more prominent (size, colouration)
        
        Old World monkeys and apes
  - Rodentia and Lagomorpha
    - Lagomorpha
      - Pikas and rabbits
      - 2 pairs of upper incisors
      - Second pair of peg-like incisors
      - Specialised gut for digesting cellulose
      - Tail quite short
    - Rodentia
      - One pair of elongated incisors and constantly growing
      - Large space between incisors and cheek teeth
      - 3 clades
      - Appox. 42% of all mammals are rodents
      - Rapid radiations (linked to fast lifecycle)
      - Worldwide distribution, many ecological adaptation to fossorial, arboreal and terrestrial
      - Convergent evolution for many ecotypes
  - Euliptoyphyla
    - Used to be insectivores and often considered as protoypic Eutherian mammals
    - Moles, moon rates (hedgehogs)
    - Primitive forms of echolocation
    - Ancestral dentition similar to early mammals
    - Specialisations include primitive echolocation and toxic saliva
  - Chiroptera
    - Yinpterochiroptera
      - Includes Megachiroptera
        Most do not echolate and search for fruit by sight (2 species use the tongue to echolate)
    - Yangochiroptera
      - Most others (13 families)
    - Microchiroptera
      - All other bats echolocate using larynx.
        Call through mouth or in some those with nose leaves, they go through nostrils
    - Characteristics
      - 1200 species
      - Cosmopolitan apart from arctic regions
      - Range of diets
  - Cetartiodactyla
    - Paraxonic feet (plane of symmetry between 3 and 4 digits)
    - Talus (ankle bone) double pulley system as a way to conserve energy over long distance movement
    - Reduced or absent canines or incisors
      - Except CWD & muntjac
    - Nasal bones not expanded backwards
  - Cetaceans
    - Almost hairless, sebaceous glands absent
    - Rostrum elongated, external pinnae lost
    - Clavicle absent, wrist and elbow joints are immobile- for paddling
  - Odd-toed ungulates
    - Mesaxonic feet
  - Hindgut fermenters
    - Including Perissodactyla
      - Mainly grazers: relatively few species remain globally. Used to be more biodiverse
  - Foregut fermenters
    - Including ruminant Artiodactyla
- Diagnostics
  - Enlarged carnassial teeth
  - Large conical canines
  - Jaw movement restricted to dorsal/ventral plane
  - Large sagittal crest (reduced)

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Modern Mammals 2

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