Primate Evolution Answers

 Primate Evolution Assignment (Week 5)

Here are the answers to the problem set for this week on Fossil Primates.  I haven’t posted the answers in table form as this would not have fit into the blog page.  I have instead broken down the information into epochs.  Understand that this is a very basic list and the true picture of fossil primates is immense.

Paleocene Epoch:  65-55.8 MYA

Primate traits:  First appearance (in different fossils) of nails, non-growing incisors and opposable toes.

Main Primate Groupings:   First Archaic Primates (not true primates)

Plesiadapiforms:  Three primary families, ALL of which are now extinct.

·         Purgatoridae – Fossil example:  Purgatorius  Possessed nails instead of claws.

·         Plesiadapidae – Fossil example:  Plesiadapis  Possessed incisors which were not ever-growing, meaning a non-rodent diet.

·         Carpolestidae – Fossil example:  Carpolestes  Possessed opposable toes for an arboreal lifestyle.  North America (Wyoming)

Adipis

Eocene Epoch:  55.8 - 33 MYA

Primate traits:  Forward-facing eyes, reduced snout, post-orbital bars, nails, larger brain-to-body ratio and opposable toes.

Main Primate Groupings:   First true primates -- Euprimates (true primates)  Massive global adaptive radiation of primates during this time period.  Two early groups (adapoid and omomyoids) followed later by descendents of modern primates.

Adapoidea (Adapoids) – Lemur-like but no firm evidence that they are direct ancestors.  Still considered an early strepsirhine.

·         North America:  Nothartcids -- Fossil example:  Cantius  Leaping quadruped.

·         Europe:  Adapids – Fossil example:  Adapis & Afradapis.    Tooth comb present?

·         Asia:  Amphipithecids – Fossil example:  Limited fossils from Burma and Thailand, extinct line.

Omomyoidea (Omomyoids) – Tarsier-like but no firm evidence that they are direct ancestors.

·         North America:   Fossil example:  Shoshonius

·         Europe:  Fossil example:  Necrolemur

·         Asia/Europe/North America:  Teilhardina  Very wide geographical dispersal.

First True Lemurs –  Strepsirhine. 

·         Africa:  Fossil Example:  Early African Bush Baby   Likely went onto colonize Madagascar, supporting African Origin of Strepsirhines.

·         Madagascar:  Fossil examples:  Archolemurs and Megaladapis (170 pounds).

First True Lorises – Early galagos and lorises, located in the Fayum Depression of Egypt.  Dental comb.

First True Tarsiers – Haplorhines, Fragmentary fossil examples in China, Egypt and Thailand.  Remains suggest little evolutionary change from Eocene to modern times, as if Tarsiers are fossils themselves… often called “living fossils”.  

Aegyptopithecus

Oliocene Epoch:  33 – 23 MYA

Primate (specifically Anthropoid) traits:  Greater sexual dimorphism, shorter snouts, greater emphasis on vision (less on smell), boney eye sockets, fused mandibles, larger brain-to-body ratio.

Main Primate Groupings:   First true Anthropoids (monkeys/apes -- haplorhines).  Keep in mind that evolution among the strepsirhines (lemurs/lorises) is ongoing but we will focus on our evolutionary line.  ALL originating in Africa, Fayum Depression

Oligopithecids – Limited fossil remains in the Fayum Depression of Egypt.

·         Fossil example:  Catopithecus  Dentition 2.1.2.3   Early Catarrhine (monkey/ape)?

Parapithecids – Abundant fossils.

·         Fossil examples:  Adipidium and Parapithecus  Dental formula of 2.1.3.3, suggesting primative Platyrrhine (New World Monkey), sexual dimorphism, social groups, arboreal quadruped.

Propliopithecids –  Possible ancestor of Catarrhines:  Old World Monkeys (OWM) and apes.

·         Fossil examples:  Aegyptopithecus  Dention 2.1.2.3, 13-18 pounds (large primate), arboreal quadruped.  Primitive Catarrhine.

Early Platyrhines (NWM) –  Originated in Africa and made their way to South America by 27 MYA (HOW?).

·         Fossil example:  Branisella – Bolivia

·         Fossil example:  Homunculus – Argentina

Proconsul

Miocene Epoch:  23 – 5.3 MYA

Primate (specifically Hominoid) traits:  Larger brain-to-body ratio, larger body size, broad nose and palate, appearance of Y-5 molars in early apes and bilophodont molars in early OWM.

Main Primate Groupings:   Appearance of first true apes (hominoidea).  We have ongoing evolution of strepsirhines and NWM, but will focus on anthropoids (apes and OWM)

Victoriapithecids – Now extinct line but many similarities to OWM (dentition, locomotion)

·         Fossil example:  Victoriapithecus  Bilophodont molars, terrestrial quadruped.

True Colobines – Fossils of extant forms of colobus monkeys appear by 9 MYA.  Adaptive radiation into Europe and Asia.

Cercopithecids – Fossil macaques and baboons.

·         Fossil example:  Theropithecus  East Africa.  Similar to modern baboons.  All lines went extinct except one, the Gelada baboon.

Proconsulodea – Early Ape, multiple species, “dental apes” due to Y-5 molars.

·         Fossil example:  Proconsul (110 pounds) and Micropithecus (22 pounds)  East Africa.  Sexual dimorphism, Y-5 molars.

Hominoidea – First True Apes

·         Fossil examples: 

o   Africa:  Dryopithecus & Ouranopithecus  Origin of African apes

o   Asia:  Sivapithecus (likely ancestor of Oranutans) and Gigantopithecus (800 pounds and possibly 9 feet tall).