Lecture 19

Question 1

Sauropod Size

Answer 1

Sauropod ‘long necks’
are gigantic in size,
with small heads
relative to their
massive bodies.
- The heaviest
sauropods reached
what is likely the
maximum weight for
a terrestrial animal at
about 70 tonnes.

The largest animal (by weight) to have ever lived is
the blue whale at a colossal 173 tonnes (190 tons). 2 1000 kg = 1 metric tonne
1.1 imperial (short) ton = 1 tonne

Question 2

Sauropod Evolutionary Novelties

Answer 2

In addition to their gigantic size, long necks and tails, and small heads
relative to the size of their bodies, other evolutionary novelties /
characteristics include pneumatic vertebrae and an air-sac system.

All saurischian dinosaurs have an air-sac system

Sauropods have air sacs all down their neck, under the hips, and through to the base of the tail. These allowed them to take in air as they breathed in and out

Question 3

Late Jurassic Morrison Formation is known as the

Answer 3

“Golden Age of Dinosaurs”

As this age was composed of the most derived sauropods

Question 4

Diplodocoids

Answer 4

Singular- Diplodocus means “diplos=double docus=beam”

Diplodocoids are easily distinguished by their long, slender skulls and slender, peg-like teeth.
- Diplodocoids were relatively light-weight as compared
to more derived sauropods.
-Their long necks and extremely long whip-like tails
make them some of the longest sauropods

Late Jurassic Morrison Fm

Late Jurassic Morrison Fm b

Question 5

Dwarf’ Sauropods

Answer 5

Amongst the diplodocoids is a lineage of ‘dwarf’ sauropods characterized by relatively short necks and smaller body size (9-10m). These
include the spectacular Amargasaurus & truly bizarre Nigersaurus. head and teeth oriented to the ground often referred to as a fern mower as it mostly ate ferns and other plants on the ground.

Several rows of replacement
teeth (see slide 12)

Question 6

Macronarians

Answer 6

The clade Macronaria is characterized by:

-large nares with a crest of bone
above (= arched nares)
- spatulate teeth
- wide-set hip bones giving them an
especially wide stance
- elongate metacarpals with either
reduced manual phalanges or none at all.

Question 7

Camarasaurus

Answer 7

Camarasaurus is a macronarian with
a blunt face and spatulate teeth. It is
the most abundant of the Late Jurassic,
North American sauropods.

Question 8

Titanosauriformes

Answer 8

At the top of the sauropod
evolutionary ladder are the
titanosauriformes our biggest sauropods, divided
into two main branches:
- Brachiosauridae
(brachiosaurid sauropods)
-Titanosauria (titanosaurs)

Longest and heaviest
sauropods of all time

Giraffe-like
proportions

Question 9

Brachiosaurus

Answer 9

Brachiosaurids have much longer forelimbs than rear limbs
(‘brachio’ = arm). Brachiosaurus is another Morrison Fm
sauropod from the “Golden Age of Dinosaurs”.

Question 10

Argentinosaurus & Patagotitan

Answer 10

Titanosaurs are of epic proportions. It is among this group
that manual phalanges were completely lost and instead these
giants walk directly on column-like metacarpals in a
horseshoe arrangement.

• In 2017, the largest known
  sauropod was Argentinosaurus,
  replaced by the slightly bigger
  Patagotitan.