fossils
- 1. Dr. Nirbhay Sudhir Pimple Department of Zoology Abasaheb Garware College Karve road Pune-4.
- 2. Pteranodon
- 3. Pteranodon Pteranodon ((/tɪˈrænədɒn/; from Greek πτερόν (pteron, "wing") and ἀνόδων (anodon, "toothless")) is a genus of pterosaur that included some of the largest known flying reptiles, with wingspans over 7 meters (23 feet). They lived during the late Cretaceous geological period of North America in present-day Kansas, Alabama, Nebraska, Wyoming, and South Dakota. More fossil specimens of Pteranodon have been found than any other pterosaur, with about 1,200 specimens known to science, many of them well preserved with nearly complete skulls and articulated skeletons. It was an important part of the animal community in the Western Interior Seaway. Pteranodon was a pterosaur, meaning that it is not a dinosaur. By definition, all dinosaurs belong to one of the two groups within Dinosauria, i.e. Saurischia or Ornithischia. As such, this excludes pterosaurs. Nonetheless, Pteranodon is frequently featured in dinosaur media and are strongly associated with dinosaurs by the general public. While not dinosaurs, pterosaurs such as Pteranodon form a clade closely related to dinosaurs as both fall within the clade Avemetatarsalia.
- 4. Pteranodon was the first pterosaur found outside of Europe. Its fossils first were found by Othniel Charles Marsh in 1870, in the Late Cretaceous Smoky Hill Chalk deposits of western Kansas. These chalk beds were deposited at the bottom of what was once the Western Interior Seaway, a large shallow sea over what now is the midsection of the North American continent. These first specimens, YPM 1160 and YPM 1161, consisted of partial wing bones, as well as a tooth from the prehistoric fish Xiphactinus, which Marsh mistakenly believed to belong to this new pterosaur (all known pterosaurs up to that point had teeth). In 1871, Marsh named the find "Pterodactylus oweni", assigning it to the well- known (but much smaller) European genus Pterodactylus. Marsh also collected more wing bones of the large pterosaur in 1871. Realizing that the name he had chosen had already been used for Harry Seeley's European pterosaur species Pterodactylus oweni in 1864, Marsh re-named his giant North American pterosaur Pterodactylus occidentalis, meaning "Western wing finger," in his 1872 description of the new specimen. He also named two additional species, based on size differences: Pterodactylus ingens (the largest specimen so far), and Pterodactylus velox (the smallest)
- 6. Archaeopteryx Archaeopteryx (/ˌɑːrkiːˈɒptərɪks/ "old wing"), sometimes referred to by its German name, Urvogel ("original bird" or "first bird"), is a genus of bird-like dinosaurs. The name derives from the ancient Greek ἀρχαῖος (archaīos), meaning "ancient", and πτέρυξ (ptéryx), meaning "feather" or "wing". Between the late 19th century and the early 21st century, Archaeopteryx was generally accepted by palaeontologists and popular reference books as the oldest known bird (member of the group Avialae).
- 7. Archaeopteryx lived in the Late Jurassic around 150 million years ago, in what is now southern Germany, and also Portugal, during a time when Europe was an archipelago of islands in a shallow warm tropical sea, much closer to the equator than it is now. The largest species of Archaeopteryx could grow to about 0.5 m (1 ft 8 in) in length. Despite their small size, broad wings, and inferred ability to fly or glide. Archaeopteryx had more in common with other small Mesozoic dinosaurs than with modern birds. In particular, they shared the following features with the dromaeosaurids and troodontids: jaws with sharp teeth, three fingers with claws, a long bony tail, hyperextensible second toes ("killing claw"), feathers (which also suggest warm-bloodedness), and various features of the skeleton.
- 8. Ammonite
- 9. Ammonite Their widely-known fossils show a ribbed spiral-form shell, in the end compartment of which lived the tentacled animal. These creatures lived in the seas from at least 400 to 65 million years ago. Their nearest living relatives are the octopus, squid, cuttlefish and Nautilus. Ammonites first appeared in the early Devonian period. They evolved from a small, straight shelled Bactridian, which was an early Nautiloid.
- 10. They quickly evolved into a variety of shapes and sizes, including some shaped like hairpins. During their evolution the ammonites faced no fewer than four catastrophic events that would eventually lead to their extinction. The first event occurred in the Upper Devonian, and the second at the end of the Permian (250 million years ago), when only two lines survived the P/Tr extinction event. The surviving species radiated and flourished throughout the Triassic period. At the end of this period (206 million years ago) they faced near extinction again, when only one genus survived. This event marked the end of the Triassic and the beginning of the Jurassic, during which time the number of ammonite species grew once more. The final catastrophe occurred at the end of the Cretaceous period when all species were annihilated and the ammonites became extinct.
- 11. Fossil fish
- 12. The evolution of fish began about 530 million years ago during the Cambrian explosion. It was during this time that the early chordates developed the skull and the vertebral column, leading to the first craniates and vertebrates. The first fish lineages belong to the Agnatha, or jawless fish. Early examples include Haikouichthys. During the late Cambrian, eel-like jawless fish called the conodonts, and small mostly armoured fish known as ostracoderms, first appeared. Most jawless fish are now extinct; but the extant lampreys may approximate ancient pre-jawed fish.
- 13. The earliest jawed vertebrates probably developed during the late Ordovician period. During the Devonian period a great increase in fish variety occurred, especially among the ostracoderms and placoderms, and also among the lobe-finned fish and early sharks. This has led to the Devonian being known as the age of fishes.
- 14. Pysa princepii
- 15. Physa is a genus of small, left-handed or sinistral, air- breathing freshwater snails, aquatic pulmonate gastropod mollusks in the family Physidae. hese small snails, like all the species in the family Physidae, have shells that are sinistral, which means that when the shell is held with the spire pointing up and the aperture facing the viewer, then the aperture is on the left- hand side. The shells of Physa species have a long and large aperture, a pointed spire, and no operculum. The shells are thin and corneous, and rather transparent.
- 17. This genus is very ancient. It is known in the fossil records from the Permian to the Quaternary (age range: from 259 to 0.0 million years ago). Fossil shells of these molluscs can be found all over the world. Genus Ostrea includes about 150 extinct species. Shell subovate, plicated, folds very irregular, superior valve flat; disks with short irregular impressed lines; cardinal area large; cartilage groove oblique, not deeply impressed; muscular impression very long and obliquely sublunate.