top of page
peter jay stein, md, ma
This 54 page synopsis of the evolution
of the Earth, the origin and progression of life, and the
emergence of humans as descendants of the hominin lineage, divides the last 4.57 billion years into progressively overlapping, imagistic, time segments, to outline our place in biological existence.
Emergent Primates II
adapted from Roberts, 2011, p. 41; Springer, 2005, pp. 82-83;
J. Kendrick, 2014; anthro.palomar.edu; and news.NationalGeographic.com, 2007
Following the extinction of the reptilian (diapsid lineage) dinosaurs, around 66 mya, and closer to 56 mya, there survived small, nocturnal mammals, the tree shrews (order Scandentia).
There then followed what may be considered the most primitive of early primates, the plesiadapiforms (e.g., Carpolestes simpsonii, an extinct, insectivore, with an abducted hallux and nail (instead of claw), allowing for arboreal grasping), also represented by Dromomys szalayi (National Geographic News, 2007), one of the earliest primate fossil remains, and possibly the last common ancestor (LCA) to modern primates, based on its pattern of molar teeth, suggestive of a diet of fruit and insects, and grasping hands and feet, to facilitate tree-living.
However, with no orbital convergence, no leaping, small brains, and with growing incisors and loss of canine teeth, this group diverged away from modern primates.
These earliest of primates probably co-evolved with flowering plants and trees, in a world characterized by tropical and semi-tropical climates, even at the poles.
In the late
Paleocene (66-56 mya),
Altiatlasius (a haplorrhine),
represents another early ancestral candidate
of modern primates,
only identified by its teeth.
Soon after this period,
in the early Eocene (56-34 mya),
are found fossil
strepsirrhines (adapids), and
considered sister clades to the
spread across several continents,
are the earliest
possibly the ancestors to the
tarsiers, monkeys, apes,
66 mya to present
end of MESOZOIC
EUPRIMATE #2 - omomyids
EUPRIMATE #1 - adapids:
discovered in Messel, Germany 1983
resembles modern lemur
basal primate characteristics
ancestor to modern lemurs & lorises
(Prosimii or Prosimian)
that suggests a common ancestor of:
tree shrews, bats, flying lemurs, and primates
image from J. Kendrick, 2014:
two groups of Eocene (56-34 mya) primates
(Eocene is Greek for "dawn" and "new")
genus Homo (9)
known by its fossil jaw and skull fragments,
an example of the earliest anthropoid.
bottom of page