Lab 7: Primate Dietary and Locomotive Anatomy

Question 1

Gumnivores

Answer 1

Group of primates (with hight metabolic rate and small body size) who chiefly feed on tree gum

Includes many callitrichids, especially marmosets

Question 2

Insectivores

Answer 2

Group of primates who rely heavily on insects for energy.

Includes platyrrhines and some of the callitrichids, and many strepsirhines

Question 3

folivores

Answer 3

Group of primates that rely primarily on leaves for food

Question 4

frugivores

Answer 4

Group of primates that rely heavily on fruits

Question 5

Primate dental morphology

Answer 5

Includes adaptations that enable primates to consume various foods

Question 6

Cheek Teeth

Answer 6

premolars and molars

reflect structural properties associated with primate diet because they function primarily as grinding instruments, breaking down food before it is chemically processed in the gut.

May include variations of cusps and shearing crests, or dental blades, which function to process different food types.

Question 7

Folivores’ teeth

Answer 7

typically have molars with high shearing crests and sharp cusps, relatively small central incisors

might have other adaptations to help them digest leafy foods.

Question 8

Insectivores’ teeth

Answer 8

typically have molars with high shearing crests and sharp cusps

Question 9

Frugivores’ teeth

Answer 9

typically possess molars with low, rounded cusps, rather than the high shearing crests of most folivores and insectivores

tend to have large, spatulated incisors for scooping fruit with their teeth

Question 10

Gumnivores

Answer 10

Stout procumbent incisors (projecting forward in a V-shape), allowing them to scrape tree bark and access the underlying sap

Question 11

bilophodont molars

Answer 11

molars with two anterior cusps and two posterior cusps that are aligned to form two ridges (or lophs)

differences in bilophodont molars reflect differences in primates’ diets

Question 12

Gingerich’s formula

Answer 12

mathematically formula for determine a primate’s diet.

provides an estimated body weight based on measurements of the second mandibular molar using equation

Body Weight (in grams) = exp [3.92 + (1.31 * ln(length*width))] / 10

based on relatively strong relationship between body size and diet.

Question 13

Kay’s threshold

Answer 13

Kay’s threshold suggests primates weighing less than 500g usually are insectivores or gumnivores, while primates over 500g tend to be either folivores or frugivores. This occurs largely due to energy demands associated with digesting different types of food as well as to the quantity and quality of food needed to support primates of different body sizes

Question 14

Primate locomotion

Answer 14

Ambulation characteristics distinctive to primates:

1) Vertical clinging and leaping
2) Quadrupedalism
a) Arboreal quadrupedalism
b) Terrestrial quadrupedalism
c) Knuckle-walking quadrupedalism
3) Suspensory behavior (including brachiation)
4) Bipedalism

Question 15

Primate locomotion: Vertical clinging and leaping

Answer 15

used by a variety of primate taxonomic groups

Strepsirhines employ vertical clinging and leaping as their primary means of mobility between separated trees in the forest or between tree trunks in the understory.

Leapers typically have long hindlimbs (legs), short, slender forelimbs (arms), and elongated tarsal bones.

Question 16

Primate locomotion: quadrupedalism (Arboreal)

Answer 16

employed across many primate taxa and is the most common form of locomotion

suitable for moving across a continuous network of tree branches

less dangerous than leaping, especially for large- bodied primates

Primates that are habitually arboreal quadrupeds have body proportions that provide stability and balance while allowing them to move quickly across tree branches

They generally have gracile arms and legs that tend to be more equal in length than the limbs of leapers (enabling their center of gravity to be closer to the tree branch, thereby helping them maintain balance)

Also have more flexed (bent) limbs for climbing on branches

Question 17

Primate locomotion: quadrupedalism (Terrestrial)

Answer 17

relatively uncommon among primates.

terrestrial quadruped primates are primarily large-bodied cercopithecoids (baboons, some macaques, the patas monkey).

Limb proportions of terrestrial quadrupeds, unlike arboreal quadrupeds, function less to maintain balance and more to attain long strides and speed while moving on the ground.

unlike their arboreal counterparts, terrestrial quadruped limbs tend to be less flexible.

tend to have long, robust limbs, narrow trunks, and short tails.

several forms of terrestrial quadrupedalism: primates walk on the palms of their hands (palmigrade), or knuckle-walking quadrupedalism where they walk on the back of the intermediate phalange

Question 18

Primate locomotion: Suspensory

Answer 18

includes brachiating (swinging from arm to arm).

Typically, used by larger-bodied species

allows them to move quickly across tree- branches that would not support them if they were arboreal quadrupeds.

The apes, and some platyrrhines, most notably the atelines (e.g., spider monkeys), employ suspensory locomotion.

tend to have long, slender upper limbs and long, curved phalanges, particularly in their hands.

Question 19

Primate locomotion: Bipedalism

Answer 19

most unique form of primate locomotion

walking on the hindlimbs without the use of the forelimbs.

only humans are obligate bipeds.

Question 20

intermembral index (IMI)

Answer 20

formula for calculating likelihood of a particular locomotive form based on forelimb:hindlimb length

[(length of humerus+length of radius)/(length of femur +length of tibia)]*100