9 - What are Primates

Question 1

Primates order

Answer 1

Mammals

Question 2

Mammalian synapomorphies

Answer 2

• Warm blooded
• Viviparity
• Lactation & mammary glands

Question 3

DIstribution of living and nonhuman primates

Answer 3

Found mostly in tropical areas e.g. central and south america, madagascar, japan

Question 4

Primate Characteristics

Answer 4

• Grasping hands & feet
• Sensory system
• Large complex brain and associated behaviour
• Dental specialisation, but generalised skeletoin

Question 5

Grasping hands and feet

Answer 5

• Opposable thumb and hallux (big toe)
• Nails, not claws
• Sensitive tactile pads
• Power grip
• Precision grip

Question 6

Power grip

Answer 6

Squeeze an object strongly between finger pads and palm, allowing full strength of the forearm muscles to be applied

Question 7

Precision grip

Answer 7

Use just the tips of your fingers for fine control (picking up a grape)

Question 8

Vision

Answer 8

• Forward facing eyes (stereoscopic vision, depth perception)
• Greater Reliance on vision (elaboration of the visual centers of the brain)
• Colour vision (at least dichromatic - blue, green, many trichromatic (RBG)

Question 9

Cranial anatomy

Answer 9

• All primates have a postorbital bar
• Higher primates (haplorhines) have a postorbital closure
• Non primate mammals generally only have postorbital process

Question 10

Olfaction

Answer 10

• Reduced reliance on olfaction
• Reduction of the snout
• Corresponding reduction of olfactory centers of the brain

Question 11

Large complex brains

Answer 11

• Large brains relative to body size
• Primates 2x larger than other mammals their size, humans 7-8x
• Also many folds (sulci & fissures) to increase surface area
• Learning & socialisation very important for
  survival
• Greater reliance on learning linked to reduction in reliance upon instinct

Question 12

High investment in offspring

Answer 12

• Fewer offspring, but greater investment in rearing them (Usually means longer lived, Typically give birth to a single young and not litters)
• Infants are relatively altricial (“requiring nourishment” vs. precocial (e.g. ungulates)
• Cling to mother, not left in nests (usually) have grasping hands (even humans)
• Longer juvenescence (juvenile development period)

Question 13

Dental formula

Answer 13

• Ancestral mammal condition = 3.1.4.3
• Primitive primates (most strepsirhines
  & NWM) = 2.1.3.3
• Later primates (OWM, Apes, Humans) = 2.1.2.3
  Chimpanzee 2.1.2.3 dental formula
  (chimpanzee - 32 teeth in total)

Question 14

Generalised skeleton

Answer 14

• Generalized limb structure
• Generalized, flexible morphology
• Non-specialized physical form

Question 15

Two groups of primates

Answer 15

• Strepsirrhines (Lemurs, Galagos, Lorises
• Haplorrhines (Tarsiers, monkeys, apes)

Question 16

Strepsirrhine characteristics

Answer 16

• Found in Sub Saharan Africa, Madagascar and Asia
• Most nocturnal
• Large eyes
• Post orbital bar only
• Rely on scent marking
• Dental comb
• Grooming claw

Question 17

Lemuriformes characteristics

Answer 17

• Only found on Madagascar & neighbouring
  Comoros Islands (endemic)
• Diverse! Because of endemism and lack of
  competition → an adaptive radiation
• Small and medium-sized today
• Diurnal and nocturnal
• Female dominance
• All nocturnal and small bodied
• Generally solitary
• Eat insects, gum and nectar, some fruits

Question 18

2 families of Lorisiformes

Answer 18

• Galagidae
• Lorisidae

Question 19

Galagidae

Answer 19

• Very active
• Fast movers
• Africa only

Question 20

Lorisidae

Answer 20

• Often immobile
• Slow movers
• Africa and Asia

Question 21

Haplorrhine Characteristics

Answer 21

• Diurnal (except tarsiers & owl monkeys)
• Reduced reliance on smell & hearing
• Flatter faces, shorter snouts
• Larger, more complex brains
• Longer juvenile dependency
• Increased parental care/investment
• Increased social complexity

Question 22

Enigmatic Tarsiers

Answer 22

• Infraorder Tarsiiformes
• Only one living genus (Tarsius)
• Retain primitive morphology
• Same genus applied to fossil from middle Eocene in China (~ 45 mya)
• Superficially they look like strepsirrhines, so used to be classified in Strepsirrhini
• Nocturnal
• Small
• Genetics tells us that they are haplorrhines

Question 23

Higher primates

Answer 23

Can be classified together as Anthropoidea

Question 24

Platyrrhini

Answer 24

• Broad, outward-facing nostrils
• 2.1.3.3. dental formula

Question 25

Catarrhini

Answer 25

• Narrow, downward facing nostrils
• 2.1.2.3 dental formula

Question 26

Platyrrhine Monkey Characteristics

Answer 26

• Five families
• Found in the Americas (Mexico, Central and South America)
  Arrived from Africa around 35 Ma
• All have tails (several prehensile)
• All arboreal
• Smaller body than cercopithecoid monkeys
• Most have 2.1.3.3 dental formula
• Minimal sexual dimorphism
• Diurnal (except Aotus – the owl monkey)

Question 27

Two major subdivisions of Catarrhine

Answer 27

• Cercopithecoid
• Hominoidea

Question 28

Superfamily Cercopithecoidea

Answer 28

• Found in wide variety of
  environments (tropical Asia, sub-Saharan Africa, North Africa, Arabian Peninsula)
• All diurnal
• Single births
• Some species are terrestrial
• Larger body size, often sexually dimorphic

Question 29

Two subfamilies of Cercopithecoidea

Answer 29

• Cercopithecinae (fruit eaters)
• Colobinae (Leaf eaters)

Question 30

Cercopithecinae

Answer 30

• Broad incisors
• Low cusps
• Cheek pouches
• Simple stomach
• Shorter limbs
• Africa and Asia
• Baoobsm macawues
• Wide range of habitats
• Diet highly variable
• Sexually dimorphic
• More terrestrial species than in any other primate group

Question 31

Colobinae

Answer 31

• Narrow incisors
• High cusps
• No cheek pouches
• Complex stomach
• Long limbs
• Africa and Asia
• All Arboreal
• Specialised folivores
• Sacculated stomach, supports bacteria for digestion of cellulose
• High shearing crests on teeth

Question 32

Superfamily Hominoidea

Answer 32

• The Apes
• No tails
• Larger size and weight
• Larger brain to body weight ratio
• More upright posture
• Longer gestation and maturationq

Question 33

Family Hylobatidae: “Lesser Apes”

Answer 33

• Gibbons & Siamangs
• Southeast Asia
• Pair-bonded (“monogamous”)
• Sexually monomorphic
• Frugivores
• Move using brachiation
• Long strong arms, short legs, elongated hook-like fingers
• Highly territorial
• Singing calls

Question 34

Family Hominidae: “Great Apes”

Answer 34

• Large bodied
• Suspensory locomotion in trees (NOT brachiation); knuckle- walking or ”fist walking” on the ground
• Sexually dimorphic
• Advanced cognitive abilities (all show tool use)
• Diverse diets & social systems
• Most investments in offspring – intense parenting and prolonged juvenile periods