lecture 10 Flashcards
What are 5 general characters of the sauropodomorpha?
- Had a small head (5% body length)
- Had at least 10 neck vertebrae that form a long neck
- additonal vertebrae in front and behind sacrum (hips)
- enormous thumb with large claw
- long femur
How long did the sauropodomorpha live for? Where were the found? How many species of them were there?
Lived for over 160 million years (the entire Time of the Dinosaurs), found on all continents , spawned over 100 species
Who were the prosauropoda and how did they become the sauropoda?
They were the primitive form of the sauropodamorpha, over time their necks became longer, heads became smaller, and they trended towards quadrapedalism
Who were the first large dinos?
The sauropoda
How long did the basic body plan of the sauropods stay the same?
for 140 Ma
What kind of food did the sauropoda’s eat? What plant arise as they did? What plants did they take advantage of?
They were herbivorous, their history parallels the rise of tall gymnosperms, sauropodomorphs were the first to take advantage of tall plants
Were saurpoda good chewers?
No
Why were sauropoda’s awlays eating?
because they were large animals with small mouths
How did the saurapoda’s claw aid in ripping veg?
made is easier to rip it into small pieces
Describe the saurapoda’s digestive system?
- Digestive system probably a
continuous, low-speed conveyor
belt of food - claw may have aided in ripping
vegetation into smaller pieces
What was the largest dinosaur? What other dinosaur may be competing?
The largest dino used to be argentinosaurus huinculensis, patagotitian may have been bigger but the estimates are made on incomplete skeletons. Both saurapodomorphs
Why were the saurapoda so big?
for defense and because they could grow that big
How did the sauropoda keep their vertebrae light?
They had pneumatic bones to keep the upper skeleton light
How did the sauropoda keep their skull light? Why did they need to?
had a extremely small delicate skull full of large openings, it had to be light because it goes at the end of a long neck
Where are the nares on saurapoda’s skull?
migrates Towards the top of the head
What are the two groups of sauropda?
Diplodocoidea and Macronaria
What are the characteristics of Diplodocoidea
- sub-rectangular snout
- fully retracted external nares
above eyes - peg-like teeth along front of jaw
forming tooth comb.
What are the characteristics of the macronaria?
- Nares as large as or larger than
orbit - Nares move towards top of skull
- Shortening and elevation of skull,
indicating more powerful biting
force
Where did early scientists think the fleshy nostrils were?
They thought it was where the bony nostrils were- at the top of the head
Why did scientists think that sauropoda were aquatic?
because they thought they were too heavy to live on land
What evidence lead scientists to believe that saurapods were not aqautic?
- water pressure too
high to allow for breathing - robust hips, dense/
pillar-like limbs, and
weight-bearing feet
suggest life on land - Sauropods are
found in a range of
environments from
swamps to lakes to
coastal areas- saurapod trackways are found in terrestrial environments
How did saurapods walk?
had narrow trackways with the tail held off the ground
What was saurapods speed?
up to 20-30 km/h, but usually
20-40 km/day
How do the trackways suggest herding behaviour among the sauropoda?
Some trackways show mixture of adults and young, with young in center of
group
How large are saurapoda footprints?
Often larger than a metre
Why did the interpretation of saurapodamorphs looking like elephants be wrong?
1) Mobile trunk “compensates” for short neck
2) Unlike elephants, facial nerve in Diplodocus is relatively small
3) Comparisons with modern crocodiles and turtles showed the probable
location of cartilage, blood vessels and other soft tissues that made up
the extinct creatures’ nasal cavities
Why do we think that the saurapoda fleshy nostrils were lower down the head?
Abundance of foramina for
blood vessels and nerves
indicates fleshy nostrils further
down the face and closer to the
mouth than to the eyes.
What are the four ways saurapodamorphs made long necks?
- Increase the length of the individual
vertebrae - Recruit vertebrae from the back into the
neck - Increase the number of neck vertebrae
- combination of the above.
What is nuchal ligament? How did it help the saurapoda necks with support?
Nuchal ligament is elastic rope of connective tissue that ran down the neck and back to support the head so the muscles didn’t have to work as hard, is was on Y-shaped neural arches of vertebrae
What else outside of nuchal ligaments did the saurapoda neck have for support?
An interlocking system of girders, made the neck act like a suspension bridge
How high could the brachiosauras raise it’s head above the ground and it’s heart? What advantage did this give?
Could raise head 13 m above ground and 8 m above the heart.
They could feed on tall trees.
Most saurapods fed within how much height above ground?
2-3m
Why dud the saurapods have long necks?
Not to eat from tall trees, but to access more food standing in one spot, lead to efficient consumption
What kind of blood pressure was needed to pump blood up 8m above the heart? Otherwise what would happen?
twice that of a giraffe, otherwise animal would faint
How did the saurapod maintain a high blood pressure?
as the walked the ribs flexed which put pressure on the vertebral artery- helped pump blood up neck
* Longer neck = more muscle = more pump
Did saurapods rear up? What prevented this?
No, they would have fainted, the shape of the pelvis prevented them from rearing up
Mammals and reptiles breathe in what direction? What does this mean for the trachea?
They breathe in and out, the entire trachea is dead space where no O2 transfer occurs
If saurapods breathed like reptiles then their long neck would contain what?
a bunch of unused air
How do giraffes reduced problem of dead space in trachea?
have narrow tracheas
How do birds breathe? How is this efficent?
the air enters air sacs goes to lungs and then to another air sac, so during in inhalation and exhalation the lung get oxygenated blood
Where are the air sacs in birds located?
in their hollow bones
The pneumatic bones in saurapods helped keep the upper skeleton light and also helped with?
breathing
How did saurapods breathe?
like bords, unidirectional
Did the degree of pneumaticity vary among diff dinos?
yes
What are the three reasons sauropods could get big?
because they had:
- A light skeleton
- Small heads because they didn’t chew (no large chewing muscles/
attachment sites)
- Unidirectional respiration
Why did having a long neck benefit the saurpods?
Lead to more efficient feeding which lead to bigger body size which lead to protection from predators
Do saurapoda have the lowest EQ of all the dinos?
yes
Did saurapoda leave eggs?
Yes, proof was seen in patagonia in 1997, eggs were the size of soccer balls and there was several layer sof eggs meaning that the mothers returned to the site year after year and buried their eggs and left or guarded them communally
How many eggs did the saurapoda lay?
lots to increase survival
How did the saurapoda smash?
maybe in the water? Likely involved a tripedal male and quadrupedal female
