TWENTY-SIX

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

haplorhines (omomyids),

considered sister clades to the

plesiadapids.

The omomyids,

spread across several continents,

are the earliest

haplorhines,

possibly the ancestors to the

tarsiers, monkeys, apes,

and

humans.

CENOZOIC ERA

66 mya to present

paleocene epoch

66-56 mya

tree shrew

(Scandentia)

and

Altiatlasius koulchii

(haplorhine?)

plesiadapiforme

primate-like

 "proto-primate"

dromomys 

Carpolestes simpsonii

(55 mya)

dinosaur extinction

end of MESOZOIC

(66 mya)

EUPRIMATE #2 -  omomyids

(haplorhines)

EUPRIMATE #1 - adapids:

(strepsirrhines)

Darwinius Masillae

47 mya

discovered in Messel, Germany 1983

Infra-order: Adapiformes

resembles modern lemur

middle Eocene

basal primate characteristics

ancestor to modern lemurs & lorises

(Prosimii or Prosimian)

 anthropoids:

NEW                     OLD

world monkeys

Archonta

mammalian superorder

that suggests a common ancestor of: 

tree shrews, bats, flying lemurs, and primates

image from J. Kendrick, 2014:

Eosimiidae

catarrhini

two groups of Eocene (56-34 mya) primates

(Eocene is Greek for "dawn" and "new")

hominoids:

gibbons

orangutans

gorillas

chimpanzees

hominins (23)

genus Homo (9)

Humans

(Homo sapiens)

Eosimias

45 mya

"Dawn Monkey"

known by its fossil jaw and skull fragments,

 an example of the earliest anthropoid.

platyrrhini