Lab 8: Primate Origins And Evolution Flashcards
plesiadapiforms
a group of early, primitive primate-like mammals, during the Paleocene (66-56 mya) in areas known today as North America and Europe.
structure of their molars and their outer ear bones are similar to those of living primates and the earliest fossil primates.
not considered true primates (The first true primates evolved from some non-primate ancestor; plesiadapiforms may be the ancestor that primates evolved from).
euprimates
groups known as (literally meaning true primates) since they possess sufficient distinguishing characteristics to qualify as primates.
Fossils show five traits indicative of primate morphology: 1) postorbital bar, 2) convergent eye orbits, 3) opposable and grasping digits, 4) nails instead of claws, and 5) petrosal auditory bulla, a thin sheet of bone that covers the inner ear in the base of the skull. The two groups of euprimates from the Eocene are the adapids and the omomyids.
During the Eocene (56-34 mya), increasing temperatures promoted new tropical habitats around the world.
euprimates: Adapids
1 of 2 subgroups of euprimates
includes 37 genera and more than 90 different species.
Fossils found in North America, Africa, Europe, and Asia.
ranged from very small (0.5 lbs for Donrusselia) to large (12 lbs for Notharctus).
grasping digits (fingers and toes) with nails, long legs, a long trunk, and long tails.
most similar to living lemurs and are considered to be primitive strepsirhines.
euprimates: Omomyids
1 of 2 subgroups of euprimates
includes 44 genera and over 100 species.
fossils found in North America, Europe, and Asia.
narrow and short snouts, large eye orbits suggesting adaptations for night vision, and hind legs and feet adapted to arboreal leaping.
most similar to living tarsiers and may represent primitive haplorhines or primitive tarsiiformes.
The Oligocene Epoch
Period of Parapithecids and Proliopithecids primates
34-23 mya
period when primate species evolved more features characteristic of higher primates: shortened snouts, eye sockets in a bony enclosure, and small eye orbits.
fossils found in the El Fayum of Egypt, parts of Africa, southern Asia and South America.
Parapithecids
1 of 2 primate groups from the Oligocene Epoch
dental formula of 2-1-3-3, and expressed a mix of ancestral and derived traits. For instance, members of one genus of parapithecids, Apidium, had almost complete 73 closure of the postorbital bones (a defining feature of higher primates), a relatively narrow snout, eyes that faced forward, and a reduction of the olfactory lobe.
Representative genera of parapithecids are Apidium, Qatrani and Parapithecus.
best known group of early haplorhines at El Fayum.
generalized dental morphology similar to modern apes and a dental formula of 2-1-2-3, the dental formula of all catarrhines.
propliopithecids
1 of 2 primate groups from the Oligocene Epoch
larger molars with a Y-5 cusp pattern, and some species exhibited sexual dimorphism in canine and body size.
features more derived and therefore are excluded from the ancestry of New World monkeys.
viewed as primitive catarrhines.
best known representative is Aegyptopithecus, found in Africa.
Dental Apes
group of primates from the Miocene Epoch: (23-5.3 mya)
structural characteristics used to define hominoids began to evolve in African primates: absence of a tail, larger bodies, and relatively larger brains.
post-cranial characteristics appeared in the mid-Miocene, after the earlier appearance of ape-like dental traits (e.g., Y-5 cusp pattern, low and rounded molar teeth). Because these primates exhibited ape-like dental morphology but a more monkey-like post-cranial morphology (i.e. arboreal quadrupedalism), they were known as “dental apes.”
