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Skull & Vertebrae
This is the very first Apatosaurus skull found connected to the neck (cervical) vertebrae. This rare find helps us better understand this dinosaur.
Skull
Look for two openings behind each eye, on the top and side of the skull. These holes are where jaw muscles attached. Having a diapsid skull (meaning “two arches”) is one of the features that helps define
dinosaurs.
Skull & Brain
The Apatosaurus skull is fossilized bone. Rock filled the cavity that contained its brain and nerves. Because they are different materials, the CT scan allows us to study them separately, without physically
dividing them.
Brain
Rock filled the space where the Apatosaurus brain and connected nerves used to be, leaving a record of its approximate brain shape, called an endocast.
Lightening Long Necks
Large openings in the neck bones reduced the weight of sauropod dinosaur necks. They may also have held air sacs used for respiration.
Cervical Ribs
Sauropod dinosaurs needed special adaptations to support their long necks. Ribs on their neck bones provided attachment points for muscles and connective tissue.
Eyes
With side-facing eyes, Apatosaurus probably had to turn its head from side to side to see what was ahead and it would have had little 3-D depth perception.
Nostrils
Apatosaurus airway openings are high on the skull, but soft tissue probably extended the location of its nostrils closer to its mouth. Think about how much air the nostrils of Apatosaurus needed to draw in to
support its massive body!
Neck Joint
The bony bulb at the base of the skull connected the head to the cervical vertebrae of the neck. This ball joint allowed the head to move freely.
Spinal Cord
The large opening in the back of the braincase is where the spinal cord entered the skull.
Sleep
The light-sensitive pineal gland lay just below the skin and produced hormones, such as melatonin, that helped to regulate sleep patterns.
Smell
We may not know what the Jurassic Period smelled like, but this shows us that Apatosaurus could smell it. This passage held a bundle of nerves called an olfactory tract. It connected the nose to the brain,
supporting the sense of smell.
Sight
This tube-like structure shows the position of the dinosaur’s optic nerve. It connected the eyes of Apatosaurus to its brain.
Biting
The largest nerve in the Apatosaurus brain was the one that carried the sense of feeling in the face. This trigeminal nerve also controlled movement of the jaw for actions such as biting.
Balance
Like other vertebrates, Apatosaurus had a structure in its inner ear for balance and orientation. The three fluid-filled canals indicated up, down and sideways directions to the brain.