Overview of the Fossil Primates ch8 Flashcards
Strepsirrihines
Members of the primate suborder Strepsirrhini, which includes lemurs and lorises
Haplorhines
Members of the primate suborder Haplorhini, which includes tarsiers, monkeys, apes, and humans
Pentadactyly
The condition of having 5 digits (fingers and toes) on each hand or foot and unfused lower arm bones
-Common trait amongst Tetrapods (four-limbed vertebrates
Derived
Being or having a feature that is not present in the ancestral form.
Orthograde
-Among the most important of derived primate traits
-More forward facing eyes
Referring to an upright body position. This term relates to the position of the head and the torso during sitting, climbing, etc., and doesn’t necessarily mean that and animal is bipedal.
Late Mesozoic
Following extinction of dinos, age of mammals begun
primates begun to divert from closely related mammalian lineages during the *Cretaceous , around extinction of dinos
Superorder
Taxonomic group ranking above and order of below a class or subclass
includes: tree shrews, flying lemurs (aka colugos) and primates
Sister groups
relationship of new clades that result from the splitting of a single common lineage
Primate Origins
cenozoic era - broad era during which most primate evolution unfolded
7 epochs-
*Paleocene 65-55.8mya; first archaic primates, plesiadapiforms
*Eocene 55.8-33 mya; early euprimates, early strepsirrhines and haplorhines
*Oligocene 33-23 mya; early catarrhines, precursors to monkeys and apes
*Miocene 23- 5.3 mya; Monkeys and apes, first human like creatures
*Pliocene 5.3- 2.6 mya; early hominin diversification
*Pleistocene 2.6- 0.105 my; early HOMO and its descendants
*Holocene 0.105mya - present; modern humans
Last Common Ancestor (LCA)
The final evolutionary link between two related groups
Crown Group
All of the taxa that come after a major speciation event. Crown groups are easier to identify than stem groups because the members possess the clade’s shared derived traits
Taxa (sing. taxon)
A taxonomic groups of any rank (e.g. species, family or class)
Stem Group
All of the taxa in a clade before a major speciation event. Stem groups are often difficult to recognize in the fossil record since they don’t often have shared derived traits found in the crown group.
*A Closer Look: Building Family Trees from Genes
-Molecular anthropology uses genetics to investigate the biology and evolution of humans and our closest relatives
- use proteins, genes, and even genomes to test hypotheses regarding relationships within the primate order
-Molecular anthro. use DNA sequences to make inferences as to how long ago primate species last shared a common ancestor
*Molecular Clock: counts mutations in DNA, using that number to estimate how long ago two species shared a common ancestor; mutations happen at a steady rate like a ticking clock
-best inferred from multiple parts of the genome in order to ensure that divergences calculated from different regions are generally consistent
-early primates were much smaller than modern ones, they had faster “molecular clocks”
Plesiadapiforms
-Between 65-52 mya during the earliest Paleocene to early Eocene, major radiation occurred of these archaic primates
-Members of an extinct group that occupies a controversial position in primate phylogeny
Considered earliest primates until 1960s, they were then treated as their own order
Newly discovered fossils has once again placed them back within primates
The Athropoids
-best known for Eocene stem strepsirrhines; included 35+ genera that we know of
-most primitive of the euprimates, organized by dental anatomy
-divided into five families ; most prominent are *Notharctids of North America (predominantly) and the *Adapids of Europe
Notharctids
-includes the genus *Cantius ; earliest of notharctids and earliest of any adapids
-primitive dental formula 2.1.4.3 indicates it was probably a fruit eater
Darwinius (“Ida”)= prominent, 47 million year old, not appear to have a dental comb or grooming claw; scientists argue that it is evidence adapids are much more than lemur relatives
Afradapis- dating to 37 mya, large- bodied adipdform genus, belongs to second major family of adapoids , most likely emigrated from Asia: supported by discoveries in southern china; appeared in Europe at the end of the Eocene and just as quickly became extinct
Adapis
Best known fossil group
-first non human fossil primate named ; first discovered by George Cuvier
-dental formula remains primitive : 2.1.4.3 and some argue a dental comb (lemur feature)
Lorisoids (lorises and galagos)
are the earliest examples of strepsirrhine primates in the fossil record
- small primitive creatures found in late Eocene deposits of *Fayum Depression in Egypt
-Likely diverged by the close of the middle Eocene
- most likely colonized Madagascar and gave crown to lemurs
-Colonization most likely occurred when these animals accidentally rafted and crossed the Mozambique Channel
Island Hopping
Traveling from one island to the next
Subfossil
*few if any truly fossilized lemur remains; there are numerous sub fossil lemurs
-Bone not old enough to have become completely mineralized as a fossil
Bilophodont
Referring to molars that have four cusps oriented in two parallel rows, resembling ridges, or “lophs.” This trait is characteristic of Old World monkeys
extinct Archaeolemur
-fused mandible and bilophodont molars; more closely resembled a monkey
-*Megaladapis = best known of the giant lemurs; 170lb ; built like a koala on steroids
Key Early Primate Names
Genus, Epoch, Site/ Region, The Big Picture
