5.9" Partial, Disarticulated Mosasaur Skull - Goulmima, Morocco

This is a beautiful 5.9" fossil Plate containing Mosasaur skull bones from Goulmima, Morocco. It contains a portion of both Maxilla (upper jaw), the right Pterygoid bone with eight teeth, a cervical (neck) vertebrae and a phalange, most likely from the front right paddle. The Pterygoid bone forms the back of the roof of the mouth just above the throat and in some reptiles contains a second set of teeth that aid in swallowing prey. A rough calculation suggests that when the skull was intact it was approximately 8 inches (20 cm) long.

This amazing plate also contains the Dentary (lower jaw) of a Pycnodus, an extinct bony fish with teeth designed for crushing hard prey like shellfish. Under magnification other Pycnodus bones can be identified, most are vertebrae. The bone in this plate is in excellent condition. The top maxilla has a a repair to the base end. This repair is an incorrect bone placement and does not reflect the correct shape of the maxilla.

Comes with a display stand.

Mosasaurs are a family of enormous marine reptiles that truly dominated the seas 90 million years ago. They ruled during the last 20-25 million years of the Cretaceous period. With the extinction of the ichthyosaurs and decline of plesiosaurs, mosasaurs diversified to become prolific apex predators in nearly every habitat of the oceanic world.

Artists reconstruction of the mosasaur Prognathodon saturator.
Artists reconstruction of the mosasaur Prognathodon saturator.

Larger mosasaurs were the great leviathans of their time, extending 10–15m, or 33–49ft long. Hainosaurus holds the record for longest mosasaur, at a seemingly impossible 57ft. The smaller genera were still an impressive 10–20ft long. Mosasaurs probably evolved from semi-aquatic scaled reptiles which were more similar in appearance to modern-day monitor lizards. They had double-hinged jaws and flexible skulls (much like that of a snake) which enabled them to gulp down their prey almost whole.

The gruesome unchewed contents of fossilized mosasaur guts have revealed a varied diet of sea birds, ammonites, smaller marine lizards, possibly shark, and even other mosasaurs. Ammonites were especially crunchy mosasaur treats. They were abundant in the Cretaceous sea, and some Mosasaurs had specialized teeth for the job.

Mosasaurs probably lurked for an ambush, rather than hunt, possibly using their powerful tail flukes for extra thrust to dart out and swallow unsuspecting prey. Non-reflective, keeled scales may have been a great advantage to the Mosasaur sneak-attack.

Mosasaurs breathed air and gave birth to live young. The bronchi leading to the lungs run parallel to each other instead of splitting apart from one another as in monitors and other terrestrial reptiles. They were well-adapted to living in the warm, shallow, epicontinental seas of the period.

Although Mosasaurs diversified and proliferated at a spectacular rate, their specialization is considered the source of their demise when marine systems collapsed at the end of the Cretaceous.

Unidentified Mosasaur, Pycnodus sp.
Goulmima, Morocco
5.9 x 5.1"
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