A few nice animals that are extinct images I found:
NYC - AMNH: Stegosaurus
Image by wallyg
Stegosaurus means "roofed reptile." Its "roof" is made up of the large plates along the ridge of the animal's back. What were they for? Originally, paleontologists speculated that the plates represented a type of armor, used for protection. But the surfaces of the plates are crisscrossed with grooves for blood vessels, indicating that they were covered with skin when the animal was alive. This led later paleontologists to speculate that the plates were used for controlling body temperature—like solar collectors or heat radiators. While that is an interesting hypothesis, it cannot be tested scientifically, since all stegosaurs are extinct. This is one of the many cases in which scientists do not have conclusive answers. Extinct dinosaurs present us with many such mysteries.
Stegosaurus offers more mysteries, such as how it could function with its tiny brain. The image of dinosaurs as massive beasts with walnut-sized brains is not true of many dinosaurs, but it is true of Stegosaurus. It has even been suggested that Stegosaurus had a second brain to control its hindquarters, since the one in its head seems to be too small to manage the entire beast. But it was, and it did. Stegosaurus had only one, small brain.
Still another mystery involves Stegosaurus's front legs. As a baby fossil, the front legs are straight up and down. As an adult fossil, however, they are splayed out to the side. Which is correct? We're not sure, since they seem to fit both ways.
Thylacine pelvis
Image by Merryjack
Collector unknown, date unknown, officially extinct 1936.
"The thylacine was noted as having a stiff and somewhat awkward gait, making it unable to run at high speed. It could also perform a bipedal hop, in a fashion similar to a kangaroo—demonstrated at various times by captive specimens. Guiler speculates that this was used as an accelerated form of motion when the animal became alarmed. The animal was also able to balance on its hind legs and stand upright for brief periods." en.wikipedia.org/wiki/Thylacine
June 2012 Specimen of the Month: Ichthyosaurus intermedius
Image by wagnerfreeinstitute
Ichthyosaurs were large marine reptiles resembling dolphins that lived during the Mesozoic Era - 250 million years ago (mya) to 65 mya. The name “Ichthyosaur” is Greek for “Fish lizard.” They were not dinosaurs but a separate group of marine vertebrates abundant during the Jurassic period. They had a wide geographic range and are estimated to have lived on earth for over 100 million years, disappearing around 65-90 mya. Ichthyosaurs were the top predator of the seas until they were replaced by Plesiosaurs in the Cretaceous period. Fossils indicate that they ate fish, cephalopods, crustaceans, and possibly other small reptiles.
Ichthyosaurs ranged in size, averaging 6-13 feet in length. Some species were smaller and some were much larger (up to 75 feet). Their large eyes and thick earbones gave them acute sight and hearing. They had long snouts with many teeth, a dorsal fin and fin-like limbs. Their long flexible bodies were built for speed and probably undulated like eels to move through the water. It is believed that they evolved from a land-based reptile that moved back into the water. Although they couldn’t leave the water, they breathed air and gave birth to live young.
Ichthyosaurus is a genus of Ichthyosaur from the Jurassic period found in Europe. They averaged 6-7 feet in length, making them one of the smaller Ichthyosaurs. Mary Anning, a woman who made five major fossil discoveries, found the first complete fossil in 1811 in Lyme Regis, England (she was 12 years old). It was an Ichthyosaurus and it became the first extinct animal known to the world and caused great debate among Christians and the scientific community. Mary Anning’s discoveries were often described by male paleontologists, one of them being William D. Conybeare. He was an English geologist, palaeontologist and clergyman famous for his work done on marine reptile fossils. He described her findings, including the Ichthyosaurus and his drawing is included here.
The Wagner Free Institute has a number of Ichthyosaur fossils, including skeletons that hang on the west wall of the museum. The specimen highlighted here can be found in case 54A and is just a fossil of the head. It was purchased from a sale in New York State in 1869.
