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An analysis of a partially complete tail fin fossil shows that Cretoxyrhina had a lunate (crescent-shaped) tail most similar with modern lamnid sharks, whale sharks, and basking sharks. The transition to tail vertebrae is estimated to be between the 140th and 160th vertebrae out of the total 230, resulting in a total tail vertebral count of 70 ...
Acanthodii or acanthodians is an extinct class of gnathostomes (jawed fishes). They are currently considered to represent a paraphyletic grade of various fish lineages basal to extant Chondrichthyes, which includes living sharks, rays, and chimaeras.
Stethacanthus is an extinct genus of shark-like cartilaginous fish which lived from the Late Devonian to Late Carboniferous epoch, dying out around 298.9 million years ago. Fossils have been found in Australia , Asia , Europe and North America .
Xenacanthida (or Xenacanthiformes) is an order or superorder of extinct shark-like chondrichthyans (cartilaginous fish) known from the Carboniferous to Triassic. They were native to freshwater, marginal marine and shallow marine habitats. [1] Some xenacanths may have grown to lengths of 5 m (16 ft). [2]
Cosmopolitodus is an extinct genus of mackerel shark that lived between thirty and one million years ago during the late Oligocene to the Early Pleistocene epochs.Its type species is Cosmopolitodus hastalis, the broad-tooth mako (other common names include the extinct giant mako and broad-tooth white shark).
Sharks could be facing extinction over the next couple of decades. Human interference is largely to blame for the species interference. Overfishing of sharks has increased as the global demand has ...
Ptychodus (from Greek: πτυχή ptyche 'fold' and Greek: ὀδούς odoús 'tooth') [1] is a genus of extinct large durophagous (shell-crushing) lamniform sharks from the Cretaceous period, spanning from the Albian to the Campanian. [2] Fossils of Ptychodus teeth are found in many Late Cretaceous marine sediments worldwide. [3]
Edestus is an extinct genus of eugeneodontid holocephalian fish known from the Late Carboniferous (Pennsylvanian) of the United Kingdom, Russia, and the United States.Most remains consist of isolated curved blades or "whorls" that are studded with teeth, that in life were situated within the midline of the upper and lower jaws.