Page 47 - Dinosaur (DK Eyewitness Books)

Double row of
neural spines

Tall neural
spine supported
a sail or ridge

KEEPING COOL
The big ornithopod Ouranosaurus had a
spine-based sail or ridge, similar to Spinosaurus’s.
Both lived in tropical north Africa, where
overheating due to intense sunlight would DOUBLE SPIKES
have been a problem. If it had a skin sail, its Argentina’s Amargasaurus (“Amarga lizard”)
sail could have shed body heat to cool it. If its was a sauropod with a double row of spikes
spines supported a fatty hump, it could have that stuck up from its neck, and smaller
insulated Ouranosaurus against the heat. spikes that ran down its back. These may
have supported a pair of skin sails, or
may have provided a bristly defense
like porcupines’ quills. Or perhaps
Amargasaurus brandished them for show.
Largest plate

Bladelike
neural spine Muscular hump

Skeleton of Bison antiquus Modern American bison
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A bison’s hump is supported by spines rising from its backbone.
The now-extinct Bison antiquuus (“ancient bison”) once roamed
throughout California. It stood nearly room-high at its shoulders
and had tall, bladelike neural spines, similar to those of
Spinosaurus and Ouranosaurus. A modern bison has smaller
spines. Its muscular hump braces its neck muscles, helping to
hold up the bison’s massive head. The dinosaurs’ neural spines
supported sails or ridges that probably acted like camels’
humps, which store energy-producing fat.

Caudal
vertebra
Caudal plate
(tail bone)
(plate on tail)

Caudal spike
Spine on (spike on tail)
caudal
vertebra

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