Lecture 8 - Fossil Apes Flashcards
ape distribution today
gorillas
Congo Basin, mid Africa
ape distribution today
chimps
Congo Basin, western Africa
ape distribution today
gibbons & orangutans
southeast Asia, Bornea & Sumatra
distribution
known hominoid distribution w/fossils
used to be a wider geographic distribution with more tolerance to different environments/climates
extant ape characteristics
- similar body plan (large)
- no tail
- y-5 pattern on lower molars
- similar locomotion (knuckle-walking, climbing, suspension)
ape body plan
pronograde vs orthograde
pronograde - spine parallel to substrate
orthograde - upright spine
ape body plan
locomotion types - quad vs biped vs suspension
quadrapedal - walks on 4 limbs
bipedal - walks on 2 limbs
suspension - hang below support
bipedalism & suspension = postural orthogrady
ape body plan
pronograde fossil ape characteristics
- long, flexible spine
- scapula is lateral
- regular diarthrodial distal radioulnar joint
- forelimb = hindlimb
- less mobile joints
- lacks strong grasping ability
- presence of tail for balance
- smaller body size
ape body plan
orthograde modern ape characteristics
- shorter, rigid spine
- scapula is posterior
- Enhanced diarthrodial distal radioulnar joint
- forelimb > hindlimb
- more mobile joints
- strong grasping ability
- no tail
- bigger body size
earliest candidate hominoids
when did ape-old world monkeys (OWM) divergence occur?
occured around 34-23 Ma (Miocene)
few late Oligocene sites in Africa
earliest candidate hominoids
Rukwapithecus & Nsungwepithecus origins & how can they be distinguished?
- stem ape & sten OWM respectively
- both c. 25 Ma
- Tanzania
- distinct ape & cercopithecine traits in teeth (Y5 molar pattern)
earliest candidate hominoids
Kamoyapithecus
- c. 27-23 Ma
- Kenya
- maxilla & mandibles only
- > 30 kg - larger body size than non-hominoids
- possibly synonymous with Rukwapithecus
primitive hominoids
what is the record like?
- fossil record is poor
- only 2 taxa - may be the same
- can see that there is a monkey-ape split through dental evidence
- hard to confirm hominoid status b/c no post-cranial
primitive hominoids
Proconsul discovery
- discovered by Mary Leakey in 1948 on Rusinga island, Kenya
- postcrania discovered later - an almost complete skeleton
- named after Consul, famous zoo chimp
primitive hominoids
Proconsul characteristics
- evidence of mosaic evolution
- Proconsul are apes b/c of dental traits but there are no postcranial adaptations
–> pronograde body plan (monkey)
–> tail loss (ape-like)
–> powerful grasping linked to balancing
primitive hominoids
Ekembo date & discovery
- c. 22-17 Ma, Kenya
- too much variability within Proconsul so new genus attributed
primitive hominoids
Ekembo characteristics
- above-branches quad
- limbs of equal length
- lacked tail
- enhanced grasping ability
- great joint mobility
- Y5 pattern
primitive hominoids
Afropithecus
- c. 17 Ma
- Ekembo -like postcrania
- plesiomorphic profile (long muzzle)
- relatively thick enamel - unusual; potentially granivore
primitive hominoids
Moropithecus
- c. 20 Ma
- discovered in Moroto, Uganda (1960s)
- 25-54 Kg, human size ish
- stiff back - hominoid-like position, first evidence of ape-like posture
- mobile joints
- potential ancestor of modern apes
origins of lesser apes
modern gibbons
gibbons (3 genera) + siamangs
* molecular clock suggests a split form other hominoids c. 18 Ma
* maybe autapomoprthic apes with no fossil record?
origins of lesser apes
Pliobates general info
- found in Spain in 2015
- c. 12 Ma
- 4-5 kg (similar to gibbons)
- cranial traits - orbit shape simialr to gibbons
- BUT pronograde w/ some suspensory behavior & primitive ear
origins of lesser apes
Pliobates origins
- mosaic of primitive and derived traits
- likely to be a stem hominoid (before divergence of hominids & hylobatids)
- ancestor of all hominoids likely small
ORDER/DATES/LOCATIONS
Rukwapithecus & Nsungapithecus - Tanzania, 25 Ma
Kamoyapithecus - Kenya, 27-23 Ma
Proconsul - Kenya,
Ekembo - Kenya, 22-17 Ma
Afropithecus - 17 Ma
Moropithecus - Uganda, 20 Ma
Pliobates - Spain, 12 Ma
