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Mosasaur Skull, Plioplatecarpus

MOSASAURS

 

 

Tylosaurs (including Mosasaurus and Hainosaurus) were the largest mosasaurs. This subfamily of mosasaurs lived in the seas during the late Cretaceous period.

(pronounced MOES-ah-SAWR) Mosasaurs were giant, serpentine (snake-like) marine reptiles. They were not dinosaurs, but were related to snakes and monitor lizards. Mosasaurs were powerful swimmers, reptiles that had adapted to living in shallow seas. These carnivores (meat-eaters) still breathed air. They were a short-lived line of reptiles that went extinct during the K-T extinction, 65 million years ago.

 

Some Mosasaurs include the Mosasaurus (40-59 ft. feet=12.5-17.6 m long with sharp teeth from the North Atlantic), Platecarpus, Tylosaurus (33-40 feet=10-12.3 m long with sharp teeth, from the North and South Atlantic), Plotosaurus, Clidastes, Plioplatecarpus, and Globidens (with flat teeth for crushing shellfish). The first Mosasaur discovered, Mosasaurus hoffmani, was found in the Netherlands in 1780.

 

ANATOMY

Mosasaurs were powerful swimmers that had a long, streamlined body. The long head had very pointed, powerful jaws with many sharp teeth. Mosasaurs had four short, paddle-like limbs adapted to life in the water. A long tail, perhaps finned, completed its serpentine body.

 

Mosasaurs probably had scaly skin; fossil impressions of scales were found near the bones of Plotocarpus, showing a snake-like skin.

 

WHEN THE MOSASAURS LIVED

The various mosasaurs lived during the late Cretaceous period, going extinct during the K-T extinction, 65 million years ago.

 

BREATHING

Although Mosasaurs lived their lives in the seas, they still needed to breathe air and had to surface periodically in order to breathe.

 

DIET

Mosasaurs were carnivores; they hunted and ate fish, turtles, mollusks, and shellfish. Fossil ammonites have been found with many telltale Mosasaur toothprints in their shells, indicating that Mosasaurs repeated bit these hard-shelled animals in order to break their shell and get to the soft meat.

 

LOCOMOTION

Mosasaurs were powerful swimmers who spent their entires lives in the seas. Mosasaurs probably swam by moving their long body in a snake-like way, also using their finned tail to propel them forwards. They steered with small, webbed feet.

 

THE NAME MOSASAUR

The name Mosasaur means "Meuse lizard," they were named for the Meuse river in Holland, near the underground limestone mine where Mosasaur fossils were first found.

 

DISCOVERY OF FOSSILS

Mosasaur fossils have been found in Europs and North America (and a few in Africa and Israel).

 

CLASSIFICATION

Mosasaur were reptiles, but not dinosaurs. They are:

 

Vertebrates

Tetrapods

Diapsids - these include all the reptiles (except turtles) and birds. They are distinguished by having two holes in the rear upper part of their skulls and two holes behind the eyes.

Order Squamata - which includes lizards and snakes

Family Mosasauridae - Mosasaurs

Subfamily Mosasaurinae long-bodied mosasaurs (Gervais, 1853) - including the genera Mosasaurus (Conybeare, 1822), Clistades (Cope, 1868), Liodon (Owen, 1840), Batrachiosaurus (Harlam, 1842), Amphekepubis (Mehl, 1929), Plotosaurus (Camp, 1951), Goronyosaurus (Azzaroli, de Guili, Ficcarelli & Torre, 1972), Globidens (Gilmore, 1912), Carinodens (Thurmond, 1969), Moanasaurus (Wiffen, 1980)

Subfamily Plioplatecarpinae short-bodied mosasaurs (Dollo, 1884) - including the genera Pliplatecarpus (Dollo, 1882), Platecarpus (Cope, 1869), Holcodus (Gibbes, 1850), Sironectes (Cope, 1840), Holosaurus (Marsh, 1880), Ancylocentrum (Schmidt, 1929), Baptosaurus (Marsh 1870), Dollosaurus (Yakovlew, 1901), Prognatosaurus (Dollo, 1889), Igdamanosaurus (Lingham-Soliar, 1991), Halisaurus (Marsh, 1869), Prognathodon, Selmasaurus, Yaguarasaurus, Plesiotylosaurus (Camp, 1942)

Subfamily Tylosaurinae enormous, short-bodied mosasaurs with abony, toothless snout extension (Williston, 1897) - including the genera Tylosaurus (Marsh, 1872), Macrosaurus (Owen, 1859), Lesticodus (Leidi, 1859), Nectoportheus (Cope, 1868), Hainosaurus (Dollo, 1885), Taniwhasaurus (Hector, 1874)

 

PLIOPLATECARPUS

(pronounced PLEE-oh-PLAT-ee-CAR-pus) Plioplatecarpus was a mosasaur, a marine reptile that swam in shallow seas during the late Cretaceous period. They were not dinosaurs. These powerful swimmers were about 20 feet (6 m) long. They had a big head, large brain, big eyes, four flippers, and a tail that ended in a fin. Carnivores, they had sharp teeth, which they used to catch fish and cephalopods. Fossils have been found in North America. One Plioplatecarpus fossils was found with a fossilized embryo inside it; this seems to indicate that Plioplatecarpus gave bith to live young. Plioplatecarpus was named by Dollo in 1884; the type species is Plioplatecarpus marshii (named to honor O. Marsh).

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Uploaded on November 15, 2011
Taken on June 28, 2011