Lecture 10: Who Are Our Primate Relatives?

Primate Conservation

504 primate species, 60% of primate species are threatened with extinction, 75% have declining populations, primates can be divided into two groups

The Strepsirrhines

Lemurs, lorises and galagos

• Rely more on olfaction (sense of smell)

• Wet nose, longer snouts (rhinarium)

• Engage more with their sense of smell “wet-nosed”

• Scent glands for communication

• Grooming claw

• Tooth comb

• 2.1.3.3 dental formula

• Post-orbital bar (not wall)

• Ring like ear region

Strepsirrhines Dental Formula

Possess a dental formula of 2.1.3.3 / 2.1.3.3, totaling 36 teeth and they are characterized by a specialized tooth comb, formed by the lower incisors and canines, used for grooming and feeding

Tooth Comb

6 teeth together = 4 incisors + 2 canines

Lemurs

Native to Madagascar and within Madagascar they inhabit a wide range of habitats (diverse), 100 species of this, famous ones include, King Julian, shaq and mouse lemur

Sifaka

Vertical clinging and leaping but doesn’t work well on the ground

Lorises and Galagos

Most closely related to lemurs, arboreal & nocturnal, they eat insects, as well as fruit; Lorises are slightly venomous, live in tropical forests in Africa (loris related species) and southeastern Asia

Lorises

• Asia & Africa

• Nocturnal

• Eat mostly insects

• Move slowly in trees

• Venomous gland & bite

Galagos

• Central African forests

• Nocturnal

• Eat fruit and insects

• Adapted for leaping

Tapetum Lucidum

Many strepsirrhines are nocturnal, also known as eye shine, reflects light back towards the retina, aids in night vision common in many animals, present in some strepsirrhines and lost in all haplorrhines

The Haplorrhines

Apes, Monkeys, and Tarsiers, diverged ~55-75 MYA

• Dry nose, shorter snouts

• More reliance on vision

• Post-orbital wall (not bar) is a closure

• Most Diurnal (active during day)

• Fused mandible (all one bone)

Tarsiers

Distant cousins of monkeys & apes; only primate that is fully faunivorous (eats only insects and small animals); long legs let them make massive leaps; eyes take up most of their head, more than its brain!; (nocturnal); can turn head 180 degrees; dental formula: upper 2.1.3.3 / lower: 1.1.3.3; share many traits with strepsirrhines AND haplorrhines, which caused a lot of debate over the years! but are haplorrhines;

Anthropoid

Is all apes and monkeys minus tarsiers — the rest of the Haplorrhines; about 70% of primates; generally larger body size; better stereoscopic/3D vision; reduced olfaction (smell); longer gestation; all taxa diurnal meaning active during the day (except owl monkey)

Monkeys of the Americas/New World Monkeys

Apes and monkeys of Africa & Asia share a common ancestor with monkeys of the Americas (Platyrrhines) and only found in tropical forests of South & Central America; some of these monkeys have prehensile tails(muscle in tail to grasp objects); famous Platyrrhines: Jack the Monkey from Pirates of the Caribbean; Dexter in Night at the Museum

Platyrrhines

Uakaris, Saki, Titi monkeys, Spider Monkeys, Woolly monkeys

• “New World Monkeys”

• 2.1.3.3. dental formula (2 incisors, 1 canine, 3 premolars, 3 molars)

• Some have prehensile tail

• Almost exclusively arboreal (lives in trees)

• Sideways facing nostrils (broad nostrils)

• Ring-like ear region

Capuchins

Much larger relative brain size compared to other monkeys, tool use and are omnivorous

Callitrichids (Marmosets, Tamarins)

Two different types of Platyrrhines but are both small and give birth to twins; insectivore, frugivore and exudativore (rely on nutrient-rich fluids emitted from plants, like tree gum and sap);

Aotus

“Owl monkey” – only nocturnal monkey; primarily frugivorous and monogamous

What traits can differentiate catarrhines from other primates?

• They have a tube-like ear region instead of ring-like ear region

• Loss of a premolar — instead of 3 its 2 premolars

• Have downward-facing nostrils (narrow nostils)

Monkeys of Africa & Asia/Old World Monkeys

Apes are closely related to monkeys of Africa & Asia (Cercopithecoids); Old world monkeys live in a wide range of habitats like Africa and Asia; some famous old world monkeys: Rafiki the mandrill from The Lion King or Japanese macaques in hot springs

Cercopithecoids

• “Old World Monkeys”

• Arboreal (live in trees) and terrestrial

• Larger brain to body size ratio

• Omnivorous

• Diverse

• Color vision

• 2.1.2.3. dental formula

• Narrow downward facing nostrils

• Tube-like ear region

Some have: Ischial callosities - thickened skin calluses that allow for comfortable, extended sitting and cheek pouches