GLGY 305 Lectures 10 - 11
1. Genasauria: Cer-
Genasaurian cerapodans:
apoda: Or-
• Cheeked ornithischians
nithopoda
• Functionally bipedal and quadrupedal
• Skull modifications for chewing
2. Why
In terms of cladistics, ornithopods are hard to pin
Ornithopo- dan
Characters down
Hard to tell
Originally thought to simply be 3-toed bipedal
ornithischi- ans
Now known they show a range of postures and
aren't so easily identified
Therefore, ornithopods include all the non-
margin- ocephalian cerapodans
3. Ornithopodan
Characters Pronounced ventral offset of premaxillary teeth
relative to maxillary teeth (later ornithopods had
a toothless premax- illa/beak)
Strong depression of jaw joint below tooth rows
Elongation of the premaxilla to contact the
prefrontal and/or lacrimal
4. Ornithopod Dis-
tribution Found on every continent
Diverse habitats and
climates
Middle Jurassic to end of Cretaceous
5. Major Groups
of Ornithopoda: Phenomenal fossil record
• Iguanodontia
6. Iguanodontian • Ankylopollexia
Characters • Hadrosauridae
, GLGY 305 Lectures 10 - 11
I ront teeth
g
u
a
n
o
d
o
n
t
i
a
n
s
l
o
s
e
f
, GLGY 305 Lectures 10 - 11
identified by loss of front teeth and broadening of front
of skull
Broadened snouts
Develop serrate margin of rhamphotheca
7. Ankylopollexian Specialized fingers and hands
Characters
identified by specialized, dexterous fingers and
hands Thumb (digit I) conical and pointed
Middle digits (II, III and IV) tipped with hooves and
fused, allowing quadrupedal locomotion (weight-
bearing)
Digit V (pinkie) flexible and opposable, able to bend
across palm like a thumb
8. Hadrosauridae
Characters 3 or more replacement teeth per tooth
position Dental battery (rows of teeth
constantly replaced)
identified by having three or more replacement
1. Genasauria: Cer-
Genasaurian cerapodans:
apoda: Or-
• Cheeked ornithischians
nithopoda
• Functionally bipedal and quadrupedal
• Skull modifications for chewing
2. Why
In terms of cladistics, ornithopods are hard to pin
Ornithopo- dan
Characters down
Hard to tell
Originally thought to simply be 3-toed bipedal
ornithischi- ans
Now known they show a range of postures and
aren't so easily identified
Therefore, ornithopods include all the non-
margin- ocephalian cerapodans
3. Ornithopodan
Characters Pronounced ventral offset of premaxillary teeth
relative to maxillary teeth (later ornithopods had
a toothless premax- illa/beak)
Strong depression of jaw joint below tooth rows
Elongation of the premaxilla to contact the
prefrontal and/or lacrimal
4. Ornithopod Dis-
tribution Found on every continent
Diverse habitats and
climates
Middle Jurassic to end of Cretaceous
5. Major Groups
of Ornithopoda: Phenomenal fossil record
• Iguanodontia
6. Iguanodontian • Ankylopollexia
Characters • Hadrosauridae
, GLGY 305 Lectures 10 - 11
I ront teeth
g
u
a
n
o
d
o
n
t
i
a
n
s
l
o
s
e
f
, GLGY 305 Lectures 10 - 11
identified by loss of front teeth and broadening of front
of skull
Broadened snouts
Develop serrate margin of rhamphotheca
7. Ankylopollexian Specialized fingers and hands
Characters
identified by specialized, dexterous fingers and
hands Thumb (digit I) conical and pointed
Middle digits (II, III and IV) tipped with hooves and
fused, allowing quadrupedal locomotion (weight-
bearing)
Digit V (pinkie) flexible and opposable, able to bend
across palm like a thumb
8. Hadrosauridae
Characters 3 or more replacement teeth per tooth
position Dental battery (rows of teeth
constantly replaced)
identified by having three or more replacement
