evolution and domestication of horses Flashcards
evolution of horses is reflected in their
limbs and teeth
modern horses belong to genus
equus
eohippus aka hyracotherium
oldest known ancestor, fox sized, omnivore dentition, hoof life structures
hyracotherium (eohuppus) forelimb and hindlimb digits
forelimb; 2-5 weight bearing, 1 vestigial
hindlimb; 2-4 weight bearing, 1 and 5 vestigial
after hyracotherium what came next
orohippus
(coexisted with hyracotherium(
orohippus digits
same as hyracotherium
forelimb; 2-5 (4 digits)
hindlimb; 2-4 (3 digits)
most dramatic change between hyracotherium and orohippus
teeth; premolar 1 smaller and premolar 4 became more molar
crests more pronounced
greater grinding ability
after orohippus what was next
mesohippus
mesohippus
3 digits on front and back feet but majority on 3rd digit
legs longer
faster
flatlands; so no protection from predators
3 premolars more molar like
sharp crests
better hrinding
after mesohippus what was next
miohippus
miohippus
extra crest in upper molars
after miohippus what was next
parahippus
parahippus
small pony size
still had 3 digits on front and back but digit 3 larger and stronger, most weight bearing
elongated skull
after parahippus what was next
merychippus
merychippus
looked like modern horse
first known grazing horse
still had 3 digits on front and back
high crowned cheek teeth