Extinct Animals
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Ichthyosaur
Ichthyosaurs ( Greek for "fish lizard" - ιχθυς or ichthus meaning "fish" and σαυρος or sauros meaning "lizard") were giant marine reptiles that resembled dolphins. Ichthyosaurs thrived during much of the Mesozoic era; based on fossil evidence, they first appeared approximately 245 million years ago ( mya ) and disappeared about 90 million years ago, about 25 million years before the dinosaurs became extinct. During the middle Triassic Period , ichthyosaurs evolved from as-yet unidentified land reptiles that moved back into the water, in a development parallel to that of the ancestors of modern-day dolphins and whales . They were particularly abundant in the Jurassic Period, until they were replaced as the top aquatic predators by another reptilian order named plesiosaurs in the Cretaceous Period.
They were weirdly shaped weaklings, giraffe-tall hang gliders forced to hurl themselves off cliffs to get airborne. At least that’s the traditional view of the flying reptiles called pterosaurs, which went extinct along with dinosaurs some 65 million years ago. But a novel idea of pterosaur flight has caught the notice of paleontologists worldwide.
Mesozoic Reptile May Have Taken a Flying Leap
Dinosaurs
Paleontologists have long thought of the coelacanth as a stodgy old slowpoke: Two modern-day species of the fish—considered living fossils because of their remarkable similarity to ancient coelacanths—typically swim in a slow, almost dawdling manner. As a group, coelacanths had apparently kept the same basic body plan for hundreds of millions of years. But now, researchers have found fossils of a sleeker coelacanth —one that likely was a speedy, shark-like predator in the ancient seas west of the supercontinent Pangaea about 240 million years ago. Unlike all previously known specimens, which have fleshy, three-lobed tails fringed with flexible fins, the new species (artist's reconstruction shown) had a stiff, crescent-shaped tail like modern-day tuna and barracuda, both of which are famed for their speed.
The Corvette of Coelacanths
Beetle fossils show their colors
Maria McNamara, a postdoctoral fellow in the Yale Department of Geology and Geophysics, used fossilized beetles to show how colors of insects have changed over time, adding to scientists’ understanding of ancient insects’ appearance. McNamara, with help from her colleagues at the Peabody Museum, the Department of Applied Physics and University College Dublin, studied the cuticles of fossilized beetle remains ranging from 15 million to 47 million years old. Using electron microscopy, McNamara saw that the metallic colors of beetles was altered, demonstrating that fossilization changed the metallic color of the beetle. The hue of a beetle depends on refraction of light within its exoskeleton.
The black and white Great Auk was a beautiful bird of bizarre proportions. Its ribbed beak was huge and unwieldy, its legs were too short and its stubby wings were far too small to carry its big body into the air. In these regards, the Great Auk’s clumsy appearance rivals that of the Dodo. And that’s not the only thing these two birds have in common. For the Great Auk too, was driven extinct by human cruelty and carelessness. The Icelandic fishermen Sigurðr Islefsson, Jón Brandsson and Ketil Ketilsson saw the last living Great Auks, in June 1844.
The Last Great Auk
The Extinct Great Auk
The Great Auk inhabited the rocky coasts and islands of the North Atlantic from Virginia , Scotland, Shetland and Ireland to Greenland and Iceland , almost to the Arctic Circle.
The Tasmanian Tiger or Thylacine have been reported but officially extinct in 1986. One of the great tragedies of the twentieth century was the extinction of the Tasmanian Tiger, the largest carnivorous marsupial to have lived in the modern world. Bad enough that this rare beast, found only on the Australian mainland, New Guinea and Tasmania is gone but that its demise was mainly caused by the incursions and depredation of European settlers. The Tasmanian Tiger was neither a feline nor a canine although it looked very much dog-like in body style and size. It shared a small classification of the genus, Thylacinus, with its cousin the Tasmanian Devil.
Tasmanian Tiger
Extinct ibex is resurrected by cloning
It has also increased the possibility that it will one day be possible to reproduce long-dead species such as woolly mammoths and even dinosaurs. Dr Jose Folch, from the Centre of Food Technology and Research of Aragon, in Zaragoza, northern Spain, led the research along with colleagues from the National Research Institute of Agriculture and Food in Madrid. He said: "The delivered kid was genetically identical to the bucardo.
About 6 waves of massive extinction are known in the history of the Earth. The last one wiped out the dinosaur world 65 million years ago and was probably due to a meteorite collision. But the recent one has no natural causes.
The Rate of Extinction: 3 Species per Hour
Glyptodon (Greek for "grooved or carved tooth") was a large, armored mammal of the family Glyptodontidae , a relative of armadillos that lived during the Pleistocene Epoch . It was roughly the same size and weight as a Volkswagen Beetle , though flatter in shape. With its rounded, bony shell and squat limbs, it superficially resembled turtles, and the much earlier dinosaurian ankylosaur , as an example of the convergent evolution of unrelated lineages into similar forms. Glyptodon is believed to have been an herbivore , grazing on grasses and other plants found near rivers and small bodies of water. Humans hunting a glyptodont Glyptodon is part of the superorder of placental mammals known as Xenarthra .
Glyptodon
Megalonyx jeffersonii , or Jefferson's ground sloth , is an extinct species of giant ground sloth that lived from the Illinoian Stage during the Middle Pleistocene (150,000 years BP ) through to the Rancholabrean of the Late Pleistocene (10,000 BCE). Its closest living relatives are the two-toed tree sloths of the genus Choloepus . This species ranged widely in North America . It belongs to the genus Megalonyx , a name proposed by Thomas Jefferson , future president of the United States , in 1797.
Megalonyx jeffersonii (Giant Land Sloth)
From the Quagga --half zebra, half horse-- to the Irish Deer --the largest deer that ever lived--, an impressive list with pictures of amazing animals we will never see. Tyrannosaurus Rex (extinct 65 million years ago) [ Wiki ] Tyrannosaurus rex was one of the largest land carnivores of all time, measuring up to 43.3 feet long, and 16.6 ft tall, with an estimated mass that goes up to 7 tons. Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to the large and powerful hindlimbs, Tyrannosaurus forelimbs were small and they retained only two digits. Fossils of T. rex have been found in North American rock formations dating to the last three million years of the Cretaceous Period at the end of the Maastrichtian stage, approximately 68.5 to 65.5 million years ago; it was among the last dinosaurs to exist prior to the Cretaceous-Tertiary extinction event.