Dinosaurs ruled the land during the Mesozoic Era, but crocodiles and their relatives unquestionably ruled the water. Prehistoric crocodiles are usually relegated to the background as supporting actors or extras in our imagined Mesozoic dramas, but the truth is that… Read More ›

Late Jurassic
Leedsichthys
Leedsichthys was a very large prehistoric saltwater fish which lived during the middle and late Jurassic Period, circa 165-150 million years ago. It was named in 1889 in honor of Alfred N. Leeds who found the first specimen. Leedsichthys belonged… Read More ›
Aegirosaurus
Aegirosaurus leptospondylus was a species of ichthyosaur which lived in the seas around Europe during the late Jurassic Period and early Cretaceous Period, roughly 147-135 million years ago. Aegirosaurus belonged to a family of ichthyosaurs called the ophthalmosaurids (Bardet and… Read More ›
Nedcolbertia: A North American elaphrosaur?
IntroductionNedcolbertia (named in honor of the American paleontologist Dr. Edward “Ned” Colbert, 1905-2001) was a mysterious and intriguing creature which inhabited western North America during the early Cretaceous Period about 140-130 million years ago. When it was officially named and… Read More ›
Arthropterygius
Arthropterygius, “jointed fin”, was a genus of ichthyosaur which lived in the Arctic Ocean during the Jurassic/Cretaceous transition period about 150 to 140 million years ago. Fossils of it have been found in Canada, Scandinavia, and Russia, and bones which… Read More ›
Gargoyleosaurus
When people think of “armored dinosaurs”, they generally think of two kinds of creature: the stegosaurs and the ankylosaurs. Both of these groups belong to the dinosaur sub-order Thyreophora, which means “armor-bearing” in ancient Greek. The dinosaur group Ankylosauria or… Read More ›
The Big Muddy: The Mowry Sea of the Early Cretaceous Period
Today the broad expanse of the Great Plains, which forms the central part of North America, is a vast area of farms, prairies, and deserts. Here, immense herds of buffalo once roamed and wild mustangs galloped. However, the land did… Read More ›
Brachiosaurus
There are some dinosaurs that everybody thinks of when they hear the word “dinosaur”. Among these is a very large sauropod which was the reptilian analog of a giraffe. I am, of course, talking about Brachiosaurus. Brachiosaurus is one of… Read More ›
List of Articles about the Morrison Formation
The Morrison Formation of western North America is my favorite geological / paleontological formation to study. Within these rock layers, which are dated to the late Jurassic Period from approximately 155 to 145 million years ago, are found the fossils… Read More ›
Fruitachampsa, the crocodile-bear-cat of the Morrison Formation
Meet the Jurassic Period’s analog of the common house cat. This is Fruitachampsa callisoni, a prehistoric reptile which inhabited western North America during the late Jurassic Period. However, this was not a dinosaur. In fact, Fruitachampsa was a distant relative… Read More ›