primates

Order Primates

General Characteristics of Primates

  • Braincase and Rostrum

    • Large rounded braincase

    • Shortened rostrum

  • Molars

    • Adapted for grinding; classified as buodont and brachyodont.

Skeletal and Mobility Features

  • Orbits

    • Orbits facing forward.

  • Skeletal Mobility

    • Unfused and highly mobile skeletal elements:

    • Radius and ulna

    • Tibia and fibula

  • Locomotion

    • Plantigrade; most species are pentadactyl (five digits on limbs).

    • Many possess opposable hallux (big toe) and pollex (thumb).

    • Possess nails rather than claws.

  • Reproductive Features

    • Usually give birth to just one young.

    • Have one pair of mammary glands.

    • Many species breed year-round.

  • Other Anatomical Features

    • Scrotal testes present in most species.

    • Baculum (os penis) present in most, except tarsiers, humans, and some cebids.

  • Ecological Characteristics

    • Primates are often ecological generalists, adapting to a variety of environments.

    • Most are arboreal or semi-arboreal.

Primate Suborders and Their Distinctions

Strepsirhini and Haplorhini

  • Strepsirhini Characteristics

    • Postorbital plate: No

    • Rostrum: Relatively long

    • Nose: Wet, naked rhinarium

    • Toothcomb: Yes

    • Toilet claw: Yes

    • Bicornuate uterus: Yes

    • Fused uterus: No

  • Haplorhini Characteristics

    • Postorbital plate: Yes

    • Rostrum: Relatively short

    • Nose: Dry, furred

    • Toothcomb: No

    • Toilet claw: No

    • Bicornuate uterus: No

    • Fused uterus: Yes

Anatomical Features of Each Suborder

  • Strepsirhini

    • Characterized by a long rostrum and postorbital bar, no plate separating the orbits from the temporal fossa.

  • Haplorhini

    • Characterized by relatively short rostrum and the presence of a postorbital plate.

Variations in Primate Snouts

  • Strepsirhini

    • Rhinarium: Wet, naked noses

    • Upper canine tooth and median groove facilitates the presence of a tooth comb configuration.

  • Haplorhini

    • Rhinarium: Dry, hairy noses; no median groove.

Primate Taxonomy and Distribution

  • Overall Structure

    • Comprised of 2 suborders, 16 families, with 439-518 species.

  • Distribution

    • Most primates live in tropics or subtropics.

Suborder: Strepsirhini

  • Family Lemuridae

    • 21 species; found in Madagascar, Comoros Islands.

  • Family Cheirogaleidae

    • 31-32 species; endemic to Madagascar.

  • Family Lepilemuridae

    • 26 species; exclusively in Madagascar.

  • Family Indridae

    • 19 species; endemic to Madagascar.

  • Family Daubentoniidae

    • 1 species; the aye-aye, found in Madagascar.

  • Family Lorisidae

    • 12 species; distributed across Central Africa, southeast Asia, and Sri Lanka.

  • Family Galagidae

    • 17-18 species; found in Africa.

Suborder: Haplorhini

  • Family Tarsiidae

    • 10-11 species; distributed in Indonesia and the Philippines.

  • Family Cebidae

    • 21-29 species; found in Central and South America.

  • Family Aotidae

    • 11 species; found in Central and South America.

  • Family Callitrichidae

    • 41-47 species; found in Central and South America.

  • Family Pithecidae

    • 43-44 species; found in Central and South America.

  • Family Atelidae

    • 25 species; found in Central and South America.

  • Family Cercopithecidae

    • 134-159 species; found in Africa, Asia, and Indonesia.

  • Family Hylobatidae

    • 18-19 species; found in Southeast Asia, China, and Indonesia.

  • Family Hominidae

    • 6-8 species; found worldwide.

Specific Families in the Suborder Strepsirhini

  • Family Daubentoniidae

    • Contains the aye-aye.

    • Distribution: Madagascar.

  • Family Lorisidae

    • Includes slow lorises, angwantibos, and pottos.

    • Distribution: Central Africa, Southeast Asia, Sri Lanka.

    • Notable Features:

    • Slow lorises have a venom gland.

  • Family Galagidae

    • Known as bushbabies and galagos.

    • Distribution: Africa.

  • Family Lemuridae

    • Characterized as true lemurs.

    • Distribution: Madagascar, Comoros Islands.

    • Includes species such as the ring-tailed lemur and the black and white ruffed lemur.

  • Family Cheirogaleidae

    • Includes mouse lemurs and dwarf lemurs.

    • Distribution: Madagascar.

  • Family Indriidae

    • Includes indri and sifakas.

    • Distribution: Madagascar.

Specific Families in the Suborder Haplorhini

  • Family Tarsiidae

    • Includes tarsiers.

    • Distribution: Indonesia, Philippines.

  • Family Cebidae

    • Includes capuchins and squirrel monkeys.

    • Distribution: Central and South America.

  • Family Callitrichidae

    • Includes marmosets and tamarins.

    • Distribution: Central and South America.

  • Family Aotidae

    • Known as night monkeys.

    • Distribution: Central and South America.

  • Family Atelidae

    • Includes howler monkeys, spider monkeys, wooly monkey, and muriquis

    • Distribution: Central and South America.

    • capable of walking upright

    • social groups of males and females

    • polygynous

    • many endangered due to habitat loss

  • Family Pithecidae

    • Includes titi monkey and sakis, uacaris, bearded sakis

    • Distribution: Central and South America.

    • omnivore

    • monogamous

    • small family groups

  • Family Cercopithecidae

    • Old World monkeys like baboons, macaques, mandrills, colobines, proboscis

    • large canines

    • brightly colored bottom, face, or scrotum

    • Distribution: Africa, Asia, and the Malay Archipelago.

  • Family Hylobatidae

    • Includes gibbons and siamangs.

    • Distribution: Southeast Asia, China, and Indonesia.

    • monogamous

    • most endangered or critically endangered

  • Family Hominidae

    • Includes gorillas, chimpanzees, orangutans, and humans.

    • Distribution: Equatorial Africa, Sumatra, and Borneo (excluding humans).

Key Characteristics of the Family Hominidae

  • Size

    • Largest primates, ranging from 40 kg to 180 kg.

  • Anatomical Features

    • Lack tails

    • long developmental periods

    • pollex and hallux opposable (though not human hallux).

    • Exhibit sexual dimorphism.

    • Show complex and varied social behavior.

Notable Species Within Hominidae

  • Gorilla

    • Gorilla gorilla (western) and Gorilla beringei (eastern)

    • largest primates

    • can climb but most stay on ground except for young

    • groups of 5 or more

  • Chimpanzee

    • Pan troglodytes

    • Bonobo (Pygmy chimpanzee)

    • Pan paniscus

    • mostly fruitivorous

    • groups of 12-100 but break up into smaller parties that change composition

    • uses tools, stones to crack nuts and sticks to dig for ants/termites

  • Orangutan

    • Pongo pygmaeus (Bornean orangutan)

    • Pongo abelii (Sumatran orangutan)

    • mostly arboreal

    • brachiators

    • mostly solitary

    • uses sticks to extract bugs

  • Human

    • Homo sapiens

    • Erect bipedalism

    • characterized by a large vaulted cranium and brain

    • lighter and more graceful skeleton than other hominids

    • less size dimorphism.

Economic Importance and Conservation Issues of Primates

  • The significance of understanding primate behavior and distribution pertains not only to biological sciences but also informs conservation strategies, as many primate species face threats due to habitat loss, poaching, and climate change.

  • good models for research