Perissodactyla and certartiodactyla

Question 1

Hooves

Answer 1

• modified claws in ungulates
• found in conjunction with reduction in digits
• adaptation for cursorial locomotion
• unguis completely surrounds subunguis (forms sole of foot)

Question 2

Ungulate foot adaptations for cursorial locomotion

Answer 2

• hooves
• reduced number of digits (toes)
  
  • main weight bearing axis passes through:
    
    1. 3rd digit: peris.
    2. 3rd and 4th digits: artio.
• lengthened foot = calcaneum doesn’t articulate with fibula
• deep groove in astragalus
• fused metapodials in some to restrict lateral movement

Question 3

Difference between shape of astragalus in Perissodactyla and Artiodactyla

Answer 3

Perissodactyla:

• “single pulley”
• bottom surface flat
• flexion/extension above astragalus

Artiodactyla:

• “double pulley”
• bottom surface pulley-shaped
• greater range of flexion/extension below astragalus

Question 4

Ungulate head ornamentation

Answer 4

• used in courtship / defense / offense
• often sexually dimorphic
• size often correlated with reproductive success
• true horns/antlers = only Artiodactyla
• ossicones = giraffe
• rhino “horn”

Question 5

Condylarthrans

Answer 5

dominant ungulate ancestors 65mya give rise to both Perissodactyla and Artiodactyla

Question 6

Tapirs, horses, zebras, rhinos

Answer 6

s.C. Theria

I.C. Eutheria

S.O. Laurasiatheria

O. Perissodactyla

• large, terrestrial herbivores
• hindgut fermentation
  
  • enlarged cecum w/ bacteria
  • fast processing of food
• complex hypsodont/lophodont teeth

Question 7

How can an Artiodactyl be identified

Answer 7

structure of foot = weight bearing axis between third and fourth digits

when present, horns always have a bony core

Question 8

Major difference between horns and antlers

Answer 8

antlers shed annually, horns are permanent structures

horn = surface made of keratin

Question 9

Pigs and peccaries

Answer 9

s.C. Theria

I.C. Eutheria

S.O. Laurasiatheria

O. Perissodactyla

s.O. Suiiformes

Question 10

Camels, llamas, alpacas, vicunas, guanacos

Answer 10

s.C. Theria

I.C. Eutheria

S.O. Laurasiatheria

O. Perissodactyla

s.O. Tylopoda

Question 11

Giraffes, Pronghorn, Deer, Cows/Goats/Antelope

Answer 11

s.C. Theria

I.C. Eutheria

S.O. Laurasiatheria

O. Perissodactyla

s.O. Ruminata

• cannon bone in all feet (most)
• no upper incisors
• selenodont molars
• horns / ossicones / antlers in males (some females)
• highly cursorial = unguligrade foot posture