Primates - Anatomy, locomotion and diet

Studying primates

are one of at least twenty Orders belonging to the Class Mammalia.

origin of primates at approximately 91 million years ago.

their close relationship to humans makes them ideal for studying humans (similar traits in different species from common ancestors).

Nonhuman primates also make excellent comparators for learning about humans via Analogy (A similar trait found in different species that arose independently.)

goal of taxa

is to create categories that reflect clade relationships, ex - clade and grades

clade

is a grouping of organisms based on relatedness that reflects a branch of the evolutionary tree.

Clade relationships are determined using traits shared by groups of taxa as well as genetic similarities.

An example of a clade would be a grouping that includes humans, chimpanzees, bonobos, and gorillas.

grades

are groupings that reflect levels of adaptation or overall similarity and not necessarily evolutionary relationships.

An example of a grade would be placing orangutans, gorillas, bonobos, and chimpanzees into a group, and excluding humans.

types of traits

ancestral traits, derived traits -

relative terms, meaning that a trait can be either one depending on the taxa being compared and where on the evolutionary tree your examining.

ancestral traits

inherited the trait from a distant ancestor, a trait that has been retained.

For example, all primates have body hair because we are mammals and all mammals share an ancestor hundreds of millions of years ago that had body hair.

derived traits

Those that have been more recently altered. This type of trait is most useful when we are trying to distinguish one group from another because derived traits tell us which taxa are more closely related to each other.

For example, humans walk on two legs - that allow us to move in this way evolved after humans split from the Genus Pan.

generalized traits

those characteristics that are useful for a wide range of things. ex - having opposable thumbs

specialized traits

those that have been modified for a specific purpose. These traits may not have a wide range of uses, but they will be very efficient at their job. ex - hooves on horses

Strepsirrhini

split from haplorrhini 70-80mya.

includes lemus, lorsises and galagos.

Retains many ancestral trait.

2 derived traits - grooming claw on foot, and tooth comb

(lower front teeth, 4 incisors, 2 canines).

have post orbital bar.

sub sections - lemuroidea and lorisodiea

haplorrhini

includes Tarsiers, monkeys of the amercias, monkeys of asia and africa and apes.

have more derived traits ,

have that full postorbital closure (full closed eye socket).

Have fovea (depression in the retina, see everything in close detail).

Heavily reliant on vision on smell.

increase in brain size relative to body size

Platyrrhini

only non human primates in central & south america ex - spider monkey, howler monkey.

have unique nose shape (flat nostrils far apart).

Smaller than catarrhines, less developed vision and arboreal living.

develop prehensile tails

catarrhini

includes cercopithecodia (monkeys of africa,) and Hominodiea.

distinctive noseshape (tear drop shaped nostrils), close together, point downwards.

one fewer per molar, 2123.

pronounced sexual dimorphism. terrestrial living

Cercopithecoidea

ancestral quadrupedal body,

2 key derived traits - two ridged molars, and ischial callosities (seat pads).

Geographically widespread, reproduce every 1-2years.

split into two groups - leaf monkeys (diet of leaves) and cheek pouch monkeys (fruit or omnivore).

Hominoidea

Apes and Humans. Y-5 molar (5 ridges in Y shape groove, ancestral trait.

unique body plans for brachiation, arms longer than legs, shorter lower back and less flexible for swinging.

clavicle no longer used to stabilize shoulder joint. no tails. short olecranon process of ulna

traits among all primates - CPTSsOPeN

1. convergent eyes.

2. 2. post orbital bar

3. 3. trichromatic colour vision

4. 4. short snouts

5. 5. opposable thumbs and big toes

6. 6. pentadactyly

7. 7. nails

different types of teeth (heterodont)

1. incisors 2. Canines 3. pre molars 4. molars

dental formula

are an identifying feature for knowing what species we are looking at.

humans (apes and old word monkeys) - 2-1-2-3.

cusps - are top parts of teeth that make occlusal / chewing surface

honing complex

really large canines, the top canine going behind bottom canine, wearing down front or anterior surface of the canine and wearing down of the back of bottom canine

generalized dentition/ specialized

generalized diet and some specialized - tarsiers - 2-1-3-3 upper, 1-1-3-3 lower.

Bc they eat mostly insects

. lemurs - dental comb (elongated and thinner incisor teeth, gummivore - eat gum and sap of trees)

Folivores

molar crests for shearing plant material

frugivore

big wide incisors to bite into fruit, low rounded for chewing and smaller molars than folivore.

Most primates (lemurs, lorises, most new world monkey), non human apes

dental formula of OWM and NWM

OWM - 2-1-2-3, 4 cusps in 2 rows. NYM - 2-1-3-3, Y 5 molar

locomotion of vertical clinging and leaping

vertical clinging and leaping - lemur, lorises and tarsiers. Body is oriented vertically, long back legs & feet.

locomotion suspensory

suspended below.

Brachiation - arm over arm swinging, very long arms, long curved fingers, mobile shoulder joint, scapula (shoulder blade) is moved to back of rib cage, mobile wrists, board chests, short lower back area, ex - gibbons

semi- brachiation

use of arms and tail, prehensile tail (not as same as arm over arm) do not have same adaptations as brachiators, similar to quad primate with fancy tail, NWM only

quadrupedialism

arboreal, terrestrial, knuckle walkers, quadrumanous scrambling

arboreal quad

legs slightly longer than arms, longer fingers and toes, narrow chest, scapula to side of rib cage, common in NYM.

terrestrial quad

arms and legs used equally, short & robust hand and feet. short tails, narrow rib cage, scapula to side of rib cage, mostly OWM.

knuckle-walkers

only gorillas, chimps, bonobos. Adapted for brachiation, spend most time on ground

. arms longer than legs and chests are elevated off ground when walking. walk on middle knuckle of 4 fingers

quadrumanous scrambling

arboreal, slow moving grasping of branches with hands and feet. ex - organutan, on ground - side of clenched feet two legs