.49" Fossil Mosasaur (Platecarpus) Tooth - Kansas

This is a .49" fossil mosasaur (Platecarpus) tooth from the Smoky Hill Chalk of the Niobrara Formation in Gove County, Kansas. It is in very good condition and likely came from a juvenile.

An artists reconstruction of Platecarpus.  By Dmitry Bogdanov Creative Commons License
An artists reconstruction of Platecarpus. By Dmitry Bogdanov Creative Commons License


Platecarpus is an extinct aquatic lizard belonging to the mosasaur family. Fossils have been found in the United States as well as a possible specimen in Belgium and Africa. It reached lengths of up to 14 feet long, half of that length being its tail. Platecarpus probably fed on fish, squid, and ammonites. Like other mosasaurs, it was initially thought to have swum in an eel-like fashion, although a recent study suggests that it swam more like modern sharks.

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 10–15 m, or 33–49 ft long. Hainosaurus holds the record for longest mosasaur, at a seemingly impossible, 57 ft. The smaller genera were still an impressive, 10–20 ft 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 Mosasaur 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.


The Niobrara Chalk was was laid down in the Late Cretaceous, when the middle to the United States was covered by the Western Interior Seaway. It underlies much of the Great Plains of the US and Canada. Evidence of vertebrate life is common throughout the formation and includes specimens of plesiosaurs, mosasaurs, and pterosaurs as well as several primitive aquatic birds.
DETAILS
SPECIES
Platecarpus coryphaeus
LOCATION
Gove County, Kansas
FORMATION
Smoky Hills Chalk, Niobrara Formation
SIZE
.49" Long
ITEM
#115732
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