Lecture 5: Haplorhini, Part 1: Tarsiers and Platyrrhines

Family Cebidae: Subfamily Cebinae

Cebus (Capuchins) Saimiri (squirrel monkeys)

Family Atelidae: Subfamily Atelinae

Four genera: Ateles (Spide monkeys), Lagothrix (woolly monkeys), Brachyteles (woolly spider monkeys or muriquis) Alouatta (howler monkeys)

Subfamily Cebinae: Behavior

Large MM-FF Diurnal Form polyspecific associations No social grooming in Saimiri Cebus uses tools

Behavior of Subfamily Pitheciinae

Little known about behavior Small groups/pairs in Pithecia to large groups in Cacajao and Chiropotes

Infraorder Platyrrhini

Made up of families Cebidae, Atelidae, and Pitheciidae. Its geographic range includes South and Central America.

What is the clade classification of tarsiers based on?

PO closure, Hemochorial placenta, lack of tepetum, orbital convergence, dry nose w/mobile lip, fovea centralis, reduced olfactory bulb, and fused frontal

Derived placental morphology

Strepsirhini (lemur) have a diffuse, epitheliochorial placenta Haplorhini (Tarsiers and Macaque) have a discoidal, haemochorial placenta

What are the key traits of Tarsius?

They have: Mostly closed post-orbital plate. Nocturnal Very large, convergent eyes No tapetum lucidum and fused frontal dry nose mobile ears two grooming claws specialized leg/ankles morphology simple, sharp teeth unfused mandible without toothcomb reduced number of teeth (dental formula is 2133/1133 presence of paraconid faunivorous

Family Atelidae: Subfamily Pitheciinae

Three genera: Pitchecia (Saki monkeys) Chiropotes (bearded saki monkeys) Cacajao (uakaris)

What are the characteristics of primitive uterine morphology?

Anthropoids have a simplex uterus. Prosimians have a bicornate uterus.

What kind of behavior do members of the Atelinae subfamily exhibit?

Ateles and Brachyteles have fission-fusion social system. Lagothrix is MM-FF. Alouatta is mostly small M-FF or MM-FF (sexually dimorphic) All diurnal, arboreal.

What kind of diet do members of the atelinae family have?

Ateles and Lagothrix are frugivorous, alouatta is folivorous and brachyteles is folivorous and frugivorous.

Family Cebidae: Subfamily Aotinae

Diet: Primarily frugivorous, few leaves and insects Behavior: Frequently use scent-marking, onlu nocturnal anthropoid today, pair-living, monogamous with significant paternal care territorial against other pairs

Summary: Tarsiiformes

Difficult to classify due to mix of primitive, derived and unusual traits (homoplastic traits?). Highly specialized leapers that forage solitarily and feed exclusively on animal matter.

What are the key traits of Platyrrhines

Distinctive nose-shape Platyrrhini means flat nose three premolars small/no diastema most have three molars. Dental traits include lacking a hypoconulid on lower molars

Polymorphic Color Vision in Platyrrhines

Gene for seeing blue/green is on an autosomal chromosome.

What is the grade classification of tarsiers based on?

Grooming claws, unfused mandible, mobile ears, multiple pairs of nipples, bicornuate uterus, nocturanal, solitary foragers, small-bodied, infant parking and oral transport of offspring, diet, and leaping adaptations.

What are the key traits of the Haplorhini?

In general, strepsirhines retain more primitive traits and haplorhines exhibit more derived characters. All but tarsiers have a fully closed post-orbital plate. Greater orbital convergence Presence of a fovea centralis No tapetum lucidum Almost entirely diurnal Reduced olfactory system No rhinarium Usually larger bodied Exhibit less leaping Larger relative brain size Almost all have hypocones They are more herbivorous Unable to synthesize vitamin C. Greater sexual dimorphism most live in social groups

Family Callithrichidae: Subfamily Callithrichinae

Includes five genera (clockwise): Callimico (Goeldi's monkeys), Callithrix (marmosets), Saguinus (tamarins), Leontopithecus (Golden-lion tamarins), Cebuella (pygmy marmosets)

Summary: Family Cebidae

Includes: Capuchins, owl monkeys, and squirrel monkeys, some have prehensile tails, includes the nocturnal monkey, some have very large brains with complex behavior, one taxon is monogramous, others MM,, MF groups

Summary: Family Atelidae

Includes: Howler monkeys, spider monkeys, woolly monkeys, and woolly spider monkeys Includes the group with truly prehensile tails Includes the largest of the platyrrhines Exhibit a wide range of social organizations

Summary: Family Cebidae

Includes: Marmosets, tamarins, and Goeldi's monkeys cooperative breeding systems, includes the smallest of all monkeys, some are exudate-specialists, all eat gums, reduced number of molars, have primarily twins (1-2 times a year).

Summary: Family Pitheciidae

Includes: Saki Monkeys, Uakaris, titi monkeys, etc. Includes a group of seed-specialists Titi monkeys have the most primitive morphology Little known, variable social organizations

What are the morphological characteristics of subfamily atelinae?

Largest of NWM, True prehensile tails, semi-brachiators, some lack thumbs, others schizodactylous, some females have a hypertrophied clitoris, alouatta specialized for folivory and loud calling.

Subfamily Callithrchinae

Morphology: Smallest of the New World Monkey 2132 (Callimico 2133) re-evolved claws Diet Marmosets specialize in eating gum and sap Other callithrichines are more fruit/insect eating.

Subfamily Callicebinae Genus Callicebus

Morphology: Monomorphic, tail-twinning, quadrupedal, primitive morphology Diet: Mostly fruit, with leaves and some insects Behavior: Diurnal pait-living, monogamous, territorial, heavy paternal care, strong pair-bond

Subfamily Aotinae: Genus Aotus

Morphopology Large eyes, no tapetum lucidum, variable resistance to malaria, monomorphic and monochromatic.

Subfamily Cebinae: Diet

Most omnivorous NWM Cebus extractive foragers Saimiri more insectivorous

What are some primitive traits that tarsiers have retained?

Multiple sets of nipples

Haplorhini

One of the two suborders that make up the order of primates.

Molecular Estimates of Divergence in Platyrrhines

Platyrrhines diverved about 20-25 mya

What are the differences in cranial traits between platyrrhines and catarrhines?

Platyrrhines have a tympanic ear rink, parietal and zygomatic bones articulate, and cranial sutures fuse late. Catarrhines have a tympanic ear tube, frontal and sphenoid bones articulate, cranial sutures fuse early.

Subfamily Cebinae: Morphology

Semi-prehensile tails, fairly large-brained, quadrupedal, saimiri smaller than cebus, saimiri has interorbital septum

Describe the general female reproductive anatomy common in Haplorhini

Simple uterus Hemochorial placenta

Subfamily Callithrichinae: Behavior

Small family groups monogamous, polygynous, or polyandrous Both sexes disperse Reproductive suppression Paternal and sibling care Chimerism Aggressive toward other groups of their own species Often form polyspecific associations

Platyrrhine characteristics

Some have prehensile tails with tactile pads. Some have claw-like nails. Many show reduced pollex opposability Schizodactyly Highly arboreal polymorphic color vision (Trichromatic, dichromatic, and monochromatic)

What are some morphological differences between Strepsirhines and Haplorhines?

Strepsirhines have an unfused frontal and Haplorhines have a fused frontal. Strepsirhines have an unfused mandible and Haplorhines have a fused mandible.

Why are tarsiers problematic to classify taxonomically?

The Traditional Grade Classification groups tarsiers with lemurs and lorises and calls this group prosimii. Monkeys, Apes, and Humans are placed together to form the anthropoidea group. Clade classification groups lemurs and lorises together under the term strepsirhini. Tarsiers are grouped with Monkeys, Apes, and Humans to form the Haplorhini group.

What are the three infraorders that make up the order of the haplorhini?

The three infraorders are tarsiidormes, platyrrhini, and catarrhini.