Ant100 Lec 5: Primates and Hominin Evolution

Primate Dentition

• Extremely hard 

• Teeth are the most common fossilized remains 

• Provides information on the diet of fossil primates 

• Focus on development, structure and how many teeth 

Diphydonty

• having 2 sets of teeth

• primates are diphydonty

• decidous teeth and adult teeth

• found in maxilla and mandible

decidous teeth

• baby teeth

• appear in earlt infant development

Adult teeth

replace the baby teeth

Parts of the toorh

• crown: covered by enamel, varying number of cusps, supported by dentin and under located pulp cavity

• neck

• root

enamel

hard substance that covers the crown of the tooth

cusps

pointed to rounded biting surface of the crown

dentin

supports the crown of the tooth which is softer than enamel

pulp cavity

under dentin and central chamber of the tooth

Heterodonty

• primates have different kinds of teeth (heterodonty)

• incisors

• canines

• premolars

• molars

anterior dentition

incisors and canines

posterior dentition

premolars and molars

teeth map of primates

2 1 2 3 (2 incisors- 8 in total, 1 canine- 4 in total, 2 premolars- 8 in total, 3 molars - 12 in total)

what parts of the cranial skeleton are capable of movement

• mandible

• few bones of inner ear

parts of the cranium

• Frontal (forehead)

• Parietal (side)

• Temporal (temple) 

• Occipital (back and bottom) 

• Foramen magnum: opening in occipital bone that the spinal cord passes through

• Zygonmatic bone (cheekbone)

3 parts of primate skeleton

• axial skeleton

• forelimbs

• hindlimbs

axial skeleton

vertebrae and ribs

parts of the forelimbs

• clavicle

• humerus

• radius

• ulna

• phalanges

parts of the hindlimbs

• pelvis

• pelvic girdle

• femur

• tibia

• fibula

• phalanges

what method is used to “know” what fossil primates were like?

comparative method: based on inferences gained from studies or form and function in extant primate (compare existing and alive primates to the structure of fossil primates)

Ex. Paleoanthropologists look at the relationship between c4rtain dental features and the diet of the extant animal and compare them to extinct species to see their morphology is similar or not indiciating that the 2 animals may have the same diet. 

Dental correlation to diet

• Posterior dentition play a bigger role in dietary aspects

• Aspects that pertain to diet: enamel thickness and dental morphology 

  • Thick enamel: hard gritty food 

  • Thin enamel: thin food (leaves)

• Anterior dentition of primates serves non dietary function it serves in mastication which is the initial preparation of food

• Incisors and canines are used to aquire/ chew food 

• Procumbent forward projecting) incisors: used to open bark and wood to get insects and plants 

• Interior dentition also serves a social and defensive role 

Frugivorous primates

• primates that primarily eat and rely on fresh fruits, pulp, and seeds for their daily nutrition

• large incisors

• uses anterior dentition

• low rounded cusps

folivorous primates

• leaf eating mammals

• smaller incisors

• uses posterior dentition

• long sharp cusps

Chewing muscles

• masseter

• temporalis

• medial pterygoid

• lateral pterygoid