Fish diversity exploded when dinosaurs went extinct. Extinct Giant Whale-Eating Whale Found. - Unlike modern sperm whales, this one had teeth in both jaws and might have eaten like killer whales.
Unraveling the Whorl-Toothed Shark. Reconstructing the anatomy of prehistoric sharks isn’t easy.
With few exceptions – an exquisitely-preserved body fossil here, some calcified bits of skeleton there – teeth make up the majority of the shark fossil record. When those teeth come from a relatively recent species with close living relatives, it is not difficult to imagine what the extinct species might have looked like. The further back in time you go, though, the more bizarre sharks become. Sometimes teeth are not enough, and one especially unusual set of teeth has vexed paleontologists for over a century.
At first sight, the teeth didn’t look like they belonged to a shark at all. Karpinsky's original vision of what Helicoprion would have looked like. No known shark had a similar buzz-saw arrangement of teeth, and, although an exact date for it could not be pinned down, Helicoprion had clearly lived long before the appearance of modern sharks. Karpinsky did not stick to his original idea. 'Extinct' Animal Found Alive and Well in New Zealand. A tiny marine animal that was thought to be extinct for the past four million years has just been found living in New Zealand.
This “living fossil” is tentacled polyp called Protulophila, and they were previously only found in fossil deposits in the northern hemisphere, specifically Europe and the Middle East. Scientists think their history extended back 170 million years into the Middle Jurassic, before they went extinct in the Pliocene; the last trace of them were found in four-million-year-old rocks. Paleontologists think that Protulophila was a colonial hydroid (resembling a hydra) that’s related to corals and sea anemones. Cambrian Creatures: Primitive sea life. Megalodon. Megalodon tooth embedded in whale vertebrae. Ichthyosaur. Ichthyosaurs (Greek for "fish lizard" - ιχθυς or ichthys meaning "fish" and σαυρος or sauros meaning "lizard") were large marine reptiles.
Ichthyosaurs belong to the order known as Ichthyosauria or Ichthyopterygia ('fish flippers' - a designation introduced by Sir Richard Owen in 1840, although the term is now used more for the parent clade of the Ichthyosauria). Science became aware of the existence of ichthyosaurs, during the early nineteenth century when the first complete skeletons were found in England. In 1834, the order Ichthyosauria was named. Later that century, many excellently preserved ichthyosaur fossils were discovered in Germany, including soft tissue remains. Since the late twentieth century there has been a revived interest in the group leading to an increased number of named ichthyosaurs from all continents, over fifty valid genera being now known. Ichthyosaur species varied from one to over sixteen metres in length. History of discoveries Early finds Beautifully-Preserved Trilobite. A Lower Cretaceous ichthyosaur graveyard in deep marine slope channel deposits at Torres del Paine National Park, southern Chile.
+ Author Affiliations Remnants of ophthalmosaurid ichthyosaurs recently discovered in the vicinity of the Tyndall Glacier in the Torres del Paine National Park of southern Chile are extremely abundant and well preserved.
After three field campaigns to the area, a total of 46 articulated and virtually complete ichthyosaur specimens, both adults and juveniles, were tentatively assigned to four different species of Ophthalmosauridae. Preservation is excellent and occasionally includes soft tissue and embryos. Fish to Amphibian Evolution. Fossils Reveal Oldest Known Vertebrate Live Birth. A 248 million-year-old fossil Ichthyosaur shows a stunningly preserved female with three embryos inside.
This pushes the timeline for vertebrate live births back 10 million years. The discovery comes a team led by Ryosuke Motani of UC Davis and was published in PLOS One. The development of offspring inside the mother is known as viviparity, which is used by most mammals along with certain examples of arthropods, sharks, and snakes. This method is opposed to oviparity, which is when a mother does not facilitate development aside from laying eggs, which is seen in birds and most reptiles, insects, and fish. Many animals utilize a variation that combines certain aspects of these two techniques. Prehistoric Shark Species Found in Arizona. - During the Middle Permian era 270 million years ago, Arizona was home to a diverse shark population. - Numerous new sharks from that period have been discovered, with three now described in detail. - The three sharks ranged from small to large, but all were toothy and ate other sharks.
The remains of several new toothy shark species, with at least three dating to 270 million years ago, have been unearthed in Arizona, according to a new study. Ichthyosaur fossil. Ammonoidea. Ammonites are excellent index fossils, and it is often possible to link the rock layer in which a particular species or genus is found to specific geological time periods.
Their fossil shells usually take the form of planispirals, although there were some helically spiraled and nonspiraled forms (known as heteromorphs). Diagnostic characters Ammonites (subclass Ammonoidea) can be distinguished by their septa, the dividing walls that separate the chambers in the phragmocone, by the nature of their sutures where the septa joint the outer shell wall, and in general by their siphuncles. Septa