A detailed over view Phylogeny of horse

It contains the over view of horse evolution

1. PHYLOGENY OF HORSE
NAME :- SRIKHANDE KARAN
Reg no :- UO4AE21S0125
COMBINATION :- CBZ
SEM :- BSC 5
TH
SEM

2. INTRODUCTION :-
The evolutionary history of the horse , known
as the phylogeny of horse.
The earliest ancestors of the modern horse
were small ,.multi –toed mammals known as
EOHIPPUS or HYRACOTHERIUM , which
lived around 60 million years ago during
EOCENE Epoch.
EVOLUTIONARY CHANGES : -
Reduction in number of toes and
elongation of the limbs ,the process calls
as digit reduction, that resulted in larger
single toed horse species marking them
Survive the open grassland habitat .

3. EOHIPPUS:-
lived during the Eocene Epoch, approx 45 -55 million years ago.
Commonly Called as DAWN HORSE , as it was the first horse of the
entire linage.
The foasils of these horse are found in N.america.
CHARACTERISTICS:-
•It was the smallest of all its members with a height of only 10 INCHES
• ( A size of a fox ) .
•Lived in the forest and eat soft vegetation, hence it was a BROWSER.
•The fore-limb were provided with 4 digits namely ( l,ll,lll and lV ) ,as the first toe formed as SPLINT .
•The hind-limbs were provided with 3 digits namely ( ll,lll and lV ) ,as 1
st
and 5
th
digits wee modified into SPLINT.
•The SPRINGING Mechanism was absent.
• Dentition was BRACHYODONT ( low Crowned ), it contained 44 teeth.
•Brain contained small and smooth CEREBRAL HEMISPHERE .
•Eohippus gave rise to several lines OROPHIPPUS,EPIHIPPUS AND MESOHIPPUS ,all the horses except
MESOHIPPUS become extinct during end of OLIGOCENE EPOCH .
•

4. MESOHIPPUS :-
It lived during the OLIGOCENE EPOCH around 30-40 million years ago.
It evolved from EPIHIPPUS and become extinct by end of OLIGOCENE
EPOCH.
Generally Called as INTERMEDIATE Horse .
•CHARACTERISTICS:-
•It’s height was about 18 – 24 inches about the Size of a
Sheep.
•All the legs were provided with only 3-digits,But in the
fore-limb V digit formed SPLINT.
•The middle toe become largest indicating a transitional
phase towards the single toe modern horses
•It was a forest dweller and browser
•The CEREBRAL HEMISPHERE were enlarged and
convoluted .
•It gave rise to MIHOHIPPUS and PARAHIPPUS that
become extinct by end of OLIGOCENE EPOCH.

5. MERYCHIPPUS :-
It lived during the MIOCENE epoch approx 20-30 million years ago.
It was evolved from PARAHIPPUS.
It was the FIRST 3 toed GRAZER.
CHARACTERISTICS :-
•It was adapted to live on grassland,It fed on
grass and as per records it was the first
GRAZER of horse evolution.
•Hence it forms a transitional stage between
BROWSER and GRAZER.
•The leg Contained 3-toes. The middle toe
alone touched the ground.
•The muscle of limbs formed efficient spring
mechanism.
•Dentition was HYPSODONT (hign Crowned).
•The CEREBRAL HEMISPHERE were still
more Complex and Convoluted.

6. It lived during PLIOCENE EPOCH , around 5-10 million years ago.
It was was a Pleistocene horse ,it descended from MERYCHIPPUS and was the main
line of evolution leading to the modern horse.
PLIOHIPPUS :-
CHARACTERISTICS :-
•It height measured upto 40 inches .
•It was the first One Toed Horse , the
side toes were reduced to SPLINT
BONES.
•It had teeth well developed for
grazing on grasslands indicating Shift
towards Open grassland Habitats.
•This fossil gave rise to morden horse
EQUUS.

7. EQUUS :-
It is the morden horse,it appeared from PLEISTOCENE EPOCH.
It includes morden horses such as EQUSS FERUS ( Wild horse ),EQUSS
CABALLUS ( domestic horse ) etc.
CHARACTERISTICS :-
•Height increased from 40 to 60 inches.
•Contained single toe and two side toes ll and lV as
SPLINT BONES.
•CEREBRAL HEMISPHERE become much complex and
convoluted.
The main course of evolution of horse occurred in
N.America ,the morden horse also evolved I N.america
during PLIOCENE EPOCH .
So as per records N. America is the mother land of
Horses.

8. Thank you