South America

Challaia

Challaia was a genus of prehistoric freshwater fish which lived in South America during the early and middle Triassic Period 240-230 million years ago. Its fossils have been found within several geological formations in western Argentina. Challaia belonged to the… Read More ›

Megaraptor

Megaraptor was a 25 foot long carnivorous dinosaur which lived in Argentina during the late Cretaceous Period 90 million years ago. The fossils of this animal were discovered by the Argentinian paleontologist Fernando Novas in northwestern Patagonia, Argentina in 1996…. Read More ›

Strophodus

Strophodus was a 10 foot long hybodont shark which specialized in eating shellfish. It appeared during the early Jurassic Period and went extinct during the early Cretaceous Period, making it one of the longest-lived shark genera in the fossil record…. Read More ›

Dakosaurus

There were numerous kinds of marine reptiles which swam in the oceans during the Mesozoic Era, including the ichthyosaurs, plesiosaurs, and mosasaurs. Less well known are the marine crocodilians, or more accurately, crocodylomorphs. These animals are known as the thalattosuchians,… Read More ›

Calamopleurus

Calamopleurus was a 3 foot long freshwater fish which lived in Brazil and northern Africa during the early and middle Cretaceous Period approximately 130-95 million years ago. Calamopleurus belonged to a family called Amiidae. Today, the only surviving amiid is… Read More ›

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 ›

Polyacrodus

NOTE: This article was originally published on May 4, 2022. On December 30, 2025, it was updated and re-uploaded. Polyacrodus was a genus of prehistoric shark, composed of several species, with fossils found in North America, South America, Europe, Asia, 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 ›

Gracilisuchus

Gracilisuchus, meaning “the slender crocodile”, was a 2-foot-long reptile which lived in South America during the middle of the Triassic Period. Its remains were discovered in northwestern Argentina within the rocks of the Chañares Formation, which are dated to about… Read More ›