Haplorrhini: Simiiformes: Platyrrhini

Question 1

Platyrrhini: Family: Aotidae
Genus: Aotus (Night monkey)

Answer 1

nocturnal w/derived lrg eyes w/out reflective tapetum like tarsier inidicates was diurnal at one point; big incisors indicate frugivore/some insects, small olfactory area in brain; monogamous w/ male care of single/twin infants-nurse from mom but w/dad rest of time; med body size; forage in group

Question 2

Platyrrhini: Family: Callitrichidae

Marmosets & Tamarins

Answer 2

adaptive radiation-highly derived; diurnal small body sized-phyletic dwarfing; insect/gum feeding derived traits w/procombant incisors (marmosets)/claw-like nails to hold on for gum feeding; both polyandry and monogamy-many males/female or one male/one female, males still take care of offspring-twinning-food sharing

Question 3

Tamarins and Marmosets

Answer 3

Red Tamarin: despite red coloring predators are color blind so cant differentiate color- used for species recognition
Marmosets: hunt like a cat (hamster sized); farm sap in trees by putting small holes thru-out to allow sap to flow slowly out to eat later; other groups raid these sap stores

Question 4

Platyrrhini: Family: Cebidae: Genus: Saimiri

Squirrel Monkey

Answer 4

med body size (1.5 lbs), variable soc. groups (25-100) multimale/multifemale groups-potential for cooperation/competition; lrg brain wt to body weight; omnivorous w/ a broad diet of fruits, insects, and small animals

Question 5

Platyrrhini: Family: Cebidae: Genus: Cebus

Capuchin monkey

Answer 5

prehensile tails; largest brain to body wt ratio for Neotropical monkeys; tool use- good ex of referential model; omnivorous; soc. org. multimale/multifemale (10-35); young males leave to prevent interbreeding- intergroup fighting as males try to join new groups-more capuchins killed by each other than any predator

Question 6

Platyrrhini: Family: Pithiciidae

Uakari and Saki

Answer 6

extreme variation in appearance; tail variation- short(uakari) or long/bushy(saki)-tails tell us about locomotion; dental adaptations allow extensive seed/nut feeding and feeding on unripe fruit w/dense jaws used like nut cracker/peel; soc. org. multimale/multifemale groups

Question 7

Platyrrhini: Family: Atelidae

Answer 7

prehensile tails, as big as German Shepard- lrg bodies (12-33 lbs) w/emphasis on suspensory locomotion & a prehensile tail

Question 8

Platyrrhini: Family Atelidae: Genus: Alouatta

Howler Monkey

Answer 8

wide habitat dist.; most folivorous of Platyrrhines (mostly sit/digest leaves/unripe fruit); enlarged hyoid bone (to howl); considerable sexual dimorphism -body size and sexual dichromatism (color); soc. org. Either one male/multifemales Or multimale/multifemale w/sperm competition

Question 9

Platyrrhini: Family: Atelidae: Genus: Ateles

Spider Monkey

Answer 9

most traits reflect adaptations for ripe fruit foraging-prehensile tail, brachiation- derived loss of external thumb on hands (still on foot) 4 external digits left on hands; soc. org. multimale/multifemale w/fission-fusion

Question 10

Platyrrhini: Family: Atelidae: Genus: Brachyteles muriqui

“wooly” spider monkey

Answer 10

lrgest new world monkey; arboreal- upright w/tail brachiation/some leaping; “faculative folivory”, slow life hisotry-slow reproduction; fluid soc. org. including fission-fusion-communicate at distances, multimale/multifemale; no sexual dimorphism, sperm competition; several Brazil forests-critically endangered ~2000 left, adapting to deforestation-terrestiral locomotion, even bipedal locomotion using tail like tripod, pelvis wider to allow for more muscle attachment- comparative model how humans evolved to be bipedal

Question 11

Simiiformes Platyrrhini specific traits

Answer 11

all species primarily arboreal; marmosets/tamarins have communal & male infant care; Cebidae/Atelidae have prehensile tails; numerous specializations-claw-like nails in marmosets, lrg strong jaw in Saki/Uakari, sperm competition in Brachyteles, hyoid bone in Howers, etc..