Primates

Primates: Characteristics

In general, characters used to define primates are not unique to the group, and tend to be associated with arboreality.

Primates: Characteristics

Teeth are bunodont and brachydont.

They exhibit specialization of the hands and digits:– Nails vs. claws.– Pads.– Ridges.

All primates have a post-orbital bar with some level of binocularity.

Enalrgement of Cerebral cortex.

Reduced olfaction and increased visual importance (stereoscopy – color).

Diet. Sociality.

Primate Evolution

Formerly, primates were divided into prosimians and anthropoids. However, this results in some unnatural groups.

Today, we divide the primates into Strepsirhines and Haplorhines.

Haplorhines include Tarsiers and simians. Strepsirhines include lemurs and lorises.

Primate Evolution

Note the position of the Plesiadapids and the Paromomyids.

Primate Evolution

The floor of the auditory bullae in primates are covered by the petrosal bone.

Primate jaws have little lateral mobility (compared to rodents).

Primates are plantigrade – some forms have lost the hallux and/or pollex.

Primate Evolution

Earliest fossils date to the Cretaceous of Europe and North America.

Plesiadapis lacked a postorbital bar, was relatively small and squirrel-like.

The tibia and fibula are separate, allowing rotation of the hind-limb. Why is this important?

Digits are long, and terminal digits had claws, not nails.

Primate Evolution

What can you infer from the skull structure of Plesiadapis?

– Note: teeth, jaw, size of braincase.

Primate Evolution Adapids are derived from the

Plesiadapids, and show up in the Eocene of Eurasia and North America. They are possible ancestors to modern lemurs. The forests of Europe and N. America were tropical in the Eocene.

Smilodectes had a postorbital bar, long tail, binocularity, no diastema, and an offset first digit on each foot. They too were small.

Primate Evolution

Omomyids probably evolved from the plesiadapids in the Oligocene and Eocene of North America and Europe. Tetonius and Necrolemur had large eyes (nocturnality?), binocularity, a short rostrum, underived teeth, large canines.

Probably gave rise to the tarsiers.

Eocene Adapid: Notharctus and Anaptomorphid: Tetonius.

Primate Evolution

Modern new world families include the Callithrichidae and Cebidae. Their modern distribution is in south and central America. Fossil record is poor.

Cercopithecidae of the old world have a better fossil record, including the Oligocene through Recent epochs.

Primate Evolution

The jaw of Parapithecus has a condyle which is high on the ascending ramus – very similar to that of modern cercopithecid primates. These are ancestral to hylobatids and hominids.

Did primates evolve in trees or on the ground? Consider the morphological characteristics we have covered.

Miopithecus: hind limb dominance?

Strepsirhines

7 families, primarily in Madagascar. These are the “prosimians” – lemurs

and lorises. Differ from Haplorhines by possession

of a rhinarium. Possess a bicornate uterus. Dental formula is 2/2, 1/1, 3/3, 3/3.

Strepsirhines

Placenta is noninvasive epitheliochorial. Young are relatively small compared to

female. These traits are plesiomorphic, and

unite the strepsirhines, probably as a monophyletic group.

Strepsirhine: Daubentoniidae Aye-ayes: Daubentonia

madagascariensis. Monotypic. Derived from same ancestral stock as

lemurs and lorises. Solitary, nocturnal insectivores of

lowland forests in Madagascar. Note long finger for tapping and extraction.

Virtually extinct – but one protected by custom, now viewed as ‘evil.’

Strepsirhine: Daubentoniidae

What do you make of this skull of an Aye-aye?

Hand and foot of an Aye-aye.

Strepsirhine: Loridae

Lorises and pottos: 4 genera and 6 species. Range includes sub-saharan Africa, India, Southeast Asia, Indonesia, and the Philippines.

Small, flattened faces, nocturnal, arboreal, dark thick wooly fur.

Pollex is 180º from remaining digits – semi opposable.

Strepsirhines: Loridae

Second digit is reduced in most.

Second toe modified as ‘toilet claw’ in some.

Insectivorous and/or frugivorous.

Live singly or paired, have vocalizations w/ some facial expressions – also scent mark.

Strepsirhines: Galagonidae

Bushbabies of Africa. 4 genera and 11 species.

Arboreal – studied extensively because of leaping ability. Have long hind-limbs and a long tail.

Galagoides demidoff (60g) to Otolemur crassicaudatus (1.2Kg).

Pentadactyl w/ second toe modified as toilet claw. Insectivorous/omnivorous.

Strepsirhines: Galagonidae

Live in groups of up to 9 animals. Use urine-marking, facial expressions,

body posture, and vocalizations that sound like a human baby crying (hence the name).

Strepsirhine: Galagonidae

Note the incisiform canine.

Note rostrum on skull of Galago.

Strepsirhines: Lemuridae 4 genera and 10 species. Madagascar only, diurnal or

crepuscular, and arboreal, but may spend time on ground.

Differ from other strepsirhines by small eyes (dirunal), and rostrum.

Eat fruit, flowers, and vegetation. Lower incisors and canines form

procumbent dental comb for auto and allogrooming.

Strepsirhine: Lemuridae

All species have ear tufts. Eulemur macaco shows sexual

dichromatism. All except Lemur catta (ring-tailed

lemur) use leaping and clinging for locomotion. Lemur catta is quadrupedal and climbs.

Social groups up to 20, scent and urine marking. Sternal glands, cutaneous arm glands. Vocal, posture, and facial communication.

Strepsirhine: Megaladapidae

Sportive lemurs – nocturnal and arboreal. Eat leaves, bark, fruit, and flowers.

Vertical clinging and leaping locomotion, has prehensile thumb.

Solitary, some scent and urine marking. Extensive vocal communication.

Strepsirhine: Cheirogaleidae

Dwarf and Mouse lemurs: 4 genera and 7 species, all in Madagascar.

Large forward facing eyes, muzzles, arboreal and nocturnal. Locomotion is squirrel-like, but Microcebus is a leaper.

Insectivorous (Microcebus) or insects and fruit.

Solitary or paired, posture, facial, vocal communication, although less than in other strepsirhines.

Strepsirhine: Indridae

3 genera and 5 species, all in Madagascar. Nocturnal and arboreal.

Includes Propithecus (sifakas – look like me) and Indri, the largest Strepsirhine primate (10Kg, short tail). Eat leaves, fruit, flowers, and bark.

Vertical clinging and leaping. Hind limb dominance.

Groups of 3-6, Vocal, scent, facial, communication.

a) lemur, b) sifaka, Indridae, c) aye-aye, and d) potto, Loridae.

Primate Evolution

Haplorhines

Note: haplorhines are found in Africa, Asia, and Central & South America. Also, they have spatulate incisors, a hemochorial placenta, and a postorbital

plate.

Tarsiidae A single genus w/ 5 species. Found in Indonesia, Malay archipelago,

and the Philippines. Fossil forms from N. America and

Europe. Extreme ability to rotate head. Crepuscular & nocturnal. Vertical

clingers and leapers. Eat insects, lizards, and spiders.

Tarsiers

Form pair bonds. Territorial. Produce a single precocial young.

Note Tarsier foot in center, compared to lemur and gorilla.

Skulls of Galago and Tarsius.

Galago (top) and Tarsius.

Cebidae

These are new world monkies. 11 genera and 58 species. Most well known forms are Howler

monkeys, capuchins, spider monkeys, uakaris, sakis, and woolly monkeys.

Primarily herbivorous/frugivorous, but night monkeys eat insects and small mammals.

Cebidae

4 genera have prehensile tails, most have prehensile hands, and the thumb is only pseudo-opposable.

Aotus and Callicebus form monogamous groups,while others form polygamous groups w/ 5 to 100 individuals.

Callithrichidae

This is the second group of new world monkeys: 5 genera and 26 species of marmosets and tamarins.

They are small, and consume insects and fruit.

Quadrupedal, but can hop. They have prehensile hands w/ non-opposable thumbs.

Callithrichidae Live in extended family groups based

on monagamous pair with as many as 15 individuals.

Maintain territories up to 40 ha. W/in group, only 1 female breeds

annualy, producing non-identical twins. In Callimico, 2 female reproduce a

single young each twice each year. All members of group carry young. Olfactory, visual, marking-urinary

communication.

Compare skull of Aye-aye and Marmoset (Saguinus geoffroyi).

Tarsier, Marmoset, spider, and Gorilla.

Cercopithecidae

These are the old world monkeys. 18 genera and 81 species, in Africa, Asia, and the Malay Archipelago.

Males have large canines, and receptive females have perineal swellings.

facial color, and facial expression are important in communication, as is vocal.

Cercopithecidae

Two major groups: cercopithecine monkeys, and colobines.

Colobus monkeys lack cheek pouches, have sacculated stomachs, and large salicary glands. Most are folivores.

Primarily arboreal, but some are more terrestrial, and all can move via quadrupedal locomotion.

Cercopithecidae

Social groups range from solitary individuals to 100 or more. Most have groups of 10 to 20, and are polygynous.

Hylobatidae

These are one of 2 families of apes: Hylobatidae and Hominidae.

Hylobatids are often lumped w/ Hominids, but Wilson and Reeder (the bible of mammalian systematics) keep them separate.

Hylobatids have 1 genus and 11 species.

Hylobatidae

Found in S.E. Asia and the Malay Archipelago.

There are 10 species of gibbons, and the Siamang.

Facial features are ‘set off’ with fur. Ture brachiators, with opposable thumbs

and fore-limb dominance. Arboreal folivores / frugivores.

Hylobatidae

Live in family groups as monogamous pair w/ juveniles.

Parental care by males. Territorial. Both sexes ‘sing’.

Hominidae

4 genera and 5 species:– Gorilla gorilla– Pan troglodytes & Pan paniscus– Pongo pygmaeus Orangutan– Homo sapiens

All lack tails K - selected life history.

Hominidae

Orangutan males have large home ranges which intersect max # of female ranges.

Brachiaters Folivores, as well as insects, birds, and

small mammals. Found only in Borneo and Sumatra.

Hominidae

Chimps live in central Africa. Sexual dimorphism. P. troglodytes will consume meat. Live in groups (12 -100 for P. t., and 6 -

15 for bonobos).

Hominidae

Gorillas Sexually dimorphic, w/ males up to 180

Kg. Tropical rain-forests of East and West

Africa. Folivores and frugivores.

Hominidae

2 populations of Gorillas. West Africa:

– folivorous & frugivorous– groups of c. 5

East Africa:– folivorous– groups of 5-30 w/ 1 silverback.

Hominidae

Communicate via facial expression, chest thumping, and vocalizations.

Compare the skulls of a cercopithechid (baboon) and a gorilla.

Molars of a) cercopithecid, b) cebid, c) cercopithecid baboon, and d) Hominid- orang.

Hominidae

Humans– lineage is 5 - 10 million years old.– Erect bipedalism– sexual dimorphism– gracile– polygyny to polyandry.– Communication is complex.

What can you say about this skull?