˗ˏˋ primate evolution ´ˎ˗ Flashcards
1
Q
what are adaptive radiations?
A
rapid diversifications of single lineages into many species which may present unique morphological features in response to different ecological settings.
2
Q
what are plesiadapiforms?
A
archaic primates.
3
Q
what are euprimates?
A
true primates.
4
Q
what are anthropoids?
A
group containing monkeys and apes, including humans.
5
Q
what is the arboreal hypothesis?
A
- many of the features of primates evolved to improve locomotion in the trees.
- typically credited as first to propose this theory was frederic wood jones, one of the leading anatomist-anthropologists of the early 1900s
- examples: grasping hands and feet for gripping different sized tree branches; flexible joints for reorienting the extremities in various different ways
6
Q
what is the visual predation hypothesis?
A
- in the late 1960s and early 1970s, matt cartmill studied and tested the idea that the characteristic features of primates evolved in the context of arboreal locomotion by looking at the example of squirrels.
- instead cartmill suggested that the unique suite of features in primates is an adaptation to detecting insect prey and guiding the hands (or feet) to catch insects
7
Q
what is the angiosperm-primate coevolution hypothesis?
A
- counterargument to the visual predation hypothesis
- primate ecologist robert sussman argued that the earliest primates were probably seeking fruit rather than insects
- fruit (and flowers) of angiosperms (flowering plants) often develop in the terminal branches.
- diffuse coevolution: the ecological interaction between whole groups of species (e.g., primates) with whole groups of other species (e.g., fruiting trees)
8
Q
what are the paleocone primate origins?
A
- mesozoic (251-65.6 mya) age of dinosaurs, mammals were small and nocturnal
- end of Cretaceous (145.5-65.5 mya), extinction of dinosaurs gave opportunity for mammals to diversify and spread
- paleocene (66-56 mya), age of mammals
- followed by eocene (56-34 million years ago)
9
Q
what are pesiadapiforms (the archaic primates)?
A
- order: plesiadapiformes
- archaic primates or primate-like placental mammals (early paleocene–late eocene)
- diverse families
- north america and west europe
- purgatorius (earliest), carpolestes
- still arguments over whether or not plesiadapiforms belong within the primate branch or outside
10
Q
what are the adapoidea?
A
- order: primates
- one of the earliest groups of euprimates (true primates; earliest records from the early eocene)
- diurnal
- herbivorous
- large
11
Q
what are the omomyoidea?
A
- order: primates; superfamily: omomyoidea
- one of the earliest groups of euprimates (true primates; earliest record in the early eocene)
- nocturnal
- insectivorous and frugivorous
- small
12
Q
what is adapoid diversity?
A
- north america and europe
- divided into six families
- important features include the hallmarks of euprimates: postorbital bar, flattened nails, grasping extremities, and a petrosal bulla.
- darwinius masillae
13
Q
what is omomyoid diversity?
A
- north american omomyoids are grouped into one family, omomyidae, with two subfamilies: anaptomorphinae and omomyinae
- important features include small size, relatively large eyes, and were probably nocturnal frugivore-insectivores
14
Q
what are trepsirrhines?
A
- eocene (56-34 mya) and oligocene (34-23 mya)
- afro-arabia
- saharagalago and karanisia
- small primates with clear affinities with crown strepsirrhines, which are missing on other primates
- the lower canine of karanisia located within a strepsirrhine-style toothcomb
15
Q
what are tarsiers?
A
- miocene (23-5 mya) fossil from thailand
- eocene (56-34 mya) fossils from china
- modern tarsiers located in southeast asia
- typically (3.5–6 inches) long
16
Q
what is the adapoid origin hypothesis?
A
- resemblances between some adapoids and some extant anthropoids include: overall robusticity of the chewing system, overall large body size, diurnal lifestyle (like small eye sockets), canine sexual dimorphism
- fell out of favor (mostly)
- many of the shared features listed above probably arose independently in the two groups as adaptations to a diet of hard and/or tough foods
- earliest anthropoids from africa do not possess these features of jaw robusticity
17
Q
what is the omomyoid origin hypothesis?
A
- cranial and hindlimb morphology similar between extant tarsiers and some omomyoids
- theory that living tarsiers and living anthropoids might be sister taxa, evolved from different omomyoids
- major arguments against this hypothesis are what forms the next hypothesis, the tarsier origin hypothesis
18
Q
what is the tarsier origin hypothesis?
A
- several paleoanthropologists have suggested that there is a relationship between tarsiers and anthropoids to the exclusion of omomyoids and adapoids
- many shared traits between tarsiers and anthropoids with soft-tissue features related to the olfactory system, loss of a hairless external nose, loss of the median cleft running from the nose to the mouth (possessed by strepsirrhines), loss of a reflective layer at the back of the eye, and similarities in carotid circulation to the brain
- arguments against include several of the similarities between tarsiers and anthropoids are probably due to similarities in the sensory systems, which might have evolved in parallel for ecological reasons
19
Q
what is the general morphology of fayum anthropoids?
A
- dental formula 2.1.2.3 or 2.1.3.3
- <1 to 15 lbs
- frugivorous
- diurnal
- quadrupeds
- leapers
20
Q
what is the propliopithecid: aegyptopithecus?
A
- large (15+ lbs)
- large chewing muscles
- low, round molars
- large canines
- long snout
- ciet of mostly fruit
- arboreal quadruped
21
Q
what are eosimiids?
A
- small size
- deep lower jaw
- pointed incisors
- lower premolars
22
Q
what are amphipithecids?
A
- up to 22 lbs
- deep jaws
- low molar cups
- folivorous, seed-eater
23
Q
what are platyrrhines?
A
- order: primates; suborder: anthropoidea; infraorder: platyrrhini
- group containing new world monkeys
- africa → south america
- eocene
- rafts of vegetation
- rapid diversification and geographic spread
24
Q
what is the miocene epoch (23.03-5.333 mya)?
A
- mammalian diversification and extinction
- initial warming trend across the globe with the expansion of subtropical forests, followed by widespread cooling and drying with the retreat of tropical forests and replacement with more open woodlands and eventually grasslands
- formations of the andes mountains (south america), and himalayan mountains (india and asia)
25
Q
what are the miocene monkeys?
A
- during the miocene, there was a wide variety of apes, but few and rare monkeys in the old world (africa and eurasia)
- these monkeys are known from northern and eastern africa between 15-12.5 mya
- small-bodied (approximately 7 kg; 15 lbs.), small-brained monkey with a long sloping face and round, narrowly spaced orbits
26
Q
what are miocene african apes?
A
- the early miocene of africa has yielded around 14 genera of early apes
- many of these taxa have been reconstructed as frugivorous arboreal quadrupeds
- short faced
- 37-110 lbs
- no caudal vertebrae (tail bones) have been found in direct association with proconsul postcrania
27
Q
what are miocene eurasian apes?
A
- long lower-molar shearing crests
- very folivorous
28
Q
what is gigantopithecus?
A
- known only from teeth and jaws
- probably weighed as much as 270 kg (595 lbs.)
- diet consisted of wide range of vegetation, including fruits, leaves, roots, and bamboo
- very large jaws and molars
- southern china
29
Q
what is laccopithecus robustus?
A
- extant lesser ape
- late miocene catarrhine from china
- shares some characteristics with modern gibbons and siamangs (including an overall small body size and a short face)
- most likely represents distantly related to extant apes
30
Q
what is yuanmoupithecus xiaoyuan?
A
- extant lesser ape
- late miocene catarrhine from china
- conflicting dental characteristics
31
Q
what is sivapithecus (formerly ramapithecus)?
A
- extant lesser ape
- closest relative to orangatan
32
Q
what is nakalipithecus nakayamai?
A
- extant lesser ape
- 9.9–9.8 mya
- large size, comparible to female gorillas or orangutans
- most likely an ancestor to gorillas
