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The evolution of tetrapods began about 400 million years ago in the Devonian Period with the earliest tetrapods evolved from lobe-finned fishes. [1] Tetrapods (under the apomorphy-based definition used on this page) are categorized as animals in the biological superclass Tetrapoda, which includes all living and extinct amphibians, reptiles, birds, and mammals.
Mosasaur bones have also been found with shark teeth embedded in them. One of the food items of mosasaurs were ammonites, molluscs with shells similar to those of Nautilus, which were abundant in the Cretaceous seas. Holes have been found in fossil shells of some ammonites, mainly Pachydiscus and Placenticeras. These were once interpreted as a ...
Ray-finned fish normally have skeletons made from true bone, though this is not true of sturgeons and paddlefish. [42] Ray-finned fish are a dominant vertebrate group, containing half of all known vertebrate species. They inhabit abyssal depths in the sea, coastal inlets and freshwater rivers and lakes, and are a major source of food for humans ...
The genus was one of the first Mesozoic marine reptiles known to science—the first fossils of Mosasaurus were found as skulls in a chalk quarry near the Dutch city of Maastricht in the late 18th century, and were initially thought to be crocodiles or whales. One skull discovered around 1780 was famously nicknamed the "great animal of Maastricht".
Dimetrodon (/ d aɪ ˈ m iː t r ə ˌ d ɒ n / ⓘ [1] or / d aɪ ˈ m ɛ t r ə ˌ d ɒ n /; [2] lit. ' two measures of teeth ') is an extinct genus of sphenacodontid synapsid tetrapods that lived during the Cisuralian age of the Early Permian period, around 295–272 million years ago.
The seven footprints, found amidst a clutter of hundreds of prehistoric animal prints, are estimated to be 115,000 years old. Many fossil and artifact windfalls have come from situations like this ...
Often, the bones of the back of the skull and the palate are incompletely ossified, apparently having partly remained cartilage. The occipital condyle is typically very convex. The stapes, the bone transmitting sound waves from the eardrum to the middle ear, is elongated and not pierced by a foramen. Pterygoid teeth are typically lacking.
Sauropterygians were a diverse group of aquatic reptiles adapted for flipper-based aquatic locomotion. This group included the plesiosaurs, nothosaurs, and placodonts. Mosasaurs were a group of large, aquatic squamates (relatives of modern-day lizards and snakes) which became the dominant marine predators towards the end of the Cretaceous period.