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 ›

Jurassic Period
Dimorphodon
Dimorphodon was a species of pterosaur that lived during the early Jurassic Period about 195-190 million years ago. It measured over three feet long from its nose to the end of its long tail (which may or may not have… Read More ›
Diplurus
Diplurus was a 3 foot long freshwater coelacanth fish which lived in the northeastern United States during the late Triassic and early Jurassic Periods, approximately 220-190 million years ago. It is divided into three species: D. longicaudatus, D. newarki, and… Read More ›
Anchisaurus
Anchisaurus was a prosauropod dinosaur whose fossils have been found in America’s northeastern states of Massachusetts and Connecticut within rocks dated to the beginning of the Jurassic Period, about 200-190 million years ago. Anchisaurus is one of the more well-known… Read More ›
Lissodus
Lissodus was a prehistoric shark which lived from the early Triassic to the middle Cretaceous Period, about 250 to 110 million years ago, give or take. Named in 1835, it was a member of a group of sharks called the… Read More ›
Polyacrodus
Polyacrodus was a genus of prehistoric shark, composed of several species, with fossils found in North America, South America, Europe, Asia, and Africa. The name Polyacrodus means “tooth with many bumps”, and it was officially named by the German paleontologist… Read More ›
Cretaceous Stegosaurs in North America? Maybe
Stegosaurus stenops. © Jason R. Abdale (August 1, 2020) Stegosaurus is one of the most famous dinosaurs in the world. With its large back plates and spiked tail, it’s commonly seen in every child’s dinosaur book and is one of… 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 ›
Semionotus
Semionotus was a genus of prehistoric fish which lived throughout the world during much of the Mesozoic Era. It was named by the famous Swiss ichthyologist and paleontologist Louis Agassiz in 1843 (type species: Semionotus bergeri). Semionotus first appeared during… Read More ›