March 28, 2024, 08:28:30 am
Welcome,
Guest
. Please
login
or
register
.
1 Hour
1 Day
Forever
Login with username, password and session length
News
: Giant crater may lie under Antarctic ice
http://space.newscientist.com/article/dn9268
Home
Help
Arcade
Gallery
Links
Staff List
Calendar
Login
Register
Allosaurus
Atlantis Online
>
Forum
>
Ages of the Earth
>
Dinosaurs
>
Allosaurus
Pages:
1
2
[
3
]
4
Go Down
« previous
next »
Print
Author
Topic: Allosaurus (Read 4248 times)
0 Members and 43 Guests are viewing this topic.
Moonfire
Superhero Member
Posts: 1120
Re: Allosaurus
«
Reply #30
on:
December 13, 2009, 02:25:27 am »
Cast of "Big Al Two"
Report Spam
Logged
Moonfire
Superhero Member
Posts: 1120
Re: Allosaurus
«
Reply #31
on:
December 13, 2009, 02:26:28 am »
Species and taxonomy
It is unclear how many species of Allosaurus there were. Seven species have been considered potentially valid since 1988 (A. amplexus,[8] A. atrox,[8] A. europaeus,[60] the type species A. fragilis,[13] the as-yet not formally described "A. jimmadseni",[6] A. maximus,[46] and A. tendagurensis[13]), although only a fraction are usually considered valid at any given time. Additionally, there are at least ten dubious or undescribed species that have been assigned to Allosaurus over the years, along with the species belonging to genera now sunk into Allosaurus. In the most recent review of basal tetanuran theropods, only A. fragilis (including A. amplexus and A. atrox as synonyms), "A. jimmadseni" (as an unnamed species), and A. tendagurensis were accepted as potentially valid species, with A. europaeus not yet proposed and A. maximus assigned to Saurophaganax.[13]
Report Spam
Logged
Moonfire
Superhero Member
Posts: 1120
Re: Allosaurus
«
Reply #32
on:
December 13, 2009, 02:28:52 am »
A. amplexus, A. atrox, A. fragilis, "A. jimmadseni", and A. maximus are all known from remains discovered in the Kimmeridgian–Tithonian Upper Jurassic-age Morrison Formation of the United States, spread across the states of Colorado, Montana, New Mexico, Oklahoma, South Dakota, Utah, and Wyoming. A. fragilis is regarded as the most common, known from the remains of at least sixty individuals.[13] Debate has gone on since the 1980s regarding the possibility that there are two common Morrison Formation species of Allosaurus, with the second known as A. atrox;[8][61] recent work has followed a "one species" interpretation,[13] with the differences seen in the Morrison Formation material attributed to individual variation.[62][63] A. europaeus was found in the Kimmeridgian-age Porto Novo Member of the Lourinhã Formation,[60] but may be the same as A. fragilis.[64] A. tendagurensis was found in Kimmeridgian-age rocks of Tendaguru, in Mtwara, Tanzania.[65] Although the most recent review tentatively accepted it as a valid species of Allosaurus, it may be a more basal tetanuran,[66] or simply a dubious theropod.[1] Although obscure, it was a large theropod, possibly around 10 meters long (33 ft) and 2.5 metric tons (2.8 short tons) in weight.[2]
Report Spam
Logged
Moonfire
Superhero Member
Posts: 1120
Re: Allosaurus
«
Reply #33
on:
December 13, 2009, 02:29:02 am »
Allosaurus is regarded as a probable synonym of the genera Antrodemus, Creosaurus, Epanterias, and Labrosaurus.[13] Most of the species that are regarded as synonyms of A. fragilis, or that were misassigned to the genus, are obscure and were based on scrappy remains. One exception is Labrosaurus ferox, named in 1884 by Marsh for an oddly formed partial lower jaw, with a prominent gap in the tooth row at the tip of the jaw, and a rear section greatly expanded and turned down.[67] Later researchers suggested that the bone was pathologic, showing an injury to the living animal,[18] and that part of the unusual form of the rear of the bone was due to plaster reconstruction.[68] It is now regarded as an example of A. fragilis.[13] Other remains thought to pertain to Allosaurus have come from across the world, including Australia,[69] Siberia,[70] and Switzerland,[1] but these fossils have been reassessed as belonging to other dinosaurs.
Report Spam
Logged
Moonfire
Superhero Member
Posts: 1120
Re: Allosaurus
«
Reply #34
on:
December 13, 2009, 02:29:50 am »
Allosaurus sp. skull (DINO 11541) from Dinosaur National Monument, still partially encased in matrix.
Report Spam
Logged
Moonfire
Superhero Member
Posts: 1120
Re: Allosaurus
«
Reply #35
on:
December 13, 2009, 02:30:19 am »
Paleoecology
Allosaurus was the most common large theropod in the vast tract of Western American fossil-bearing rock known as the Morrison Formation, accounting for 70 to 75% of theropod specimens,[5] and as such was at the top trophic level of the Morrison food web.[71] The Morrison Formation is interpreted as a semiarid environment with distinct wet and dry seasons, and flat floodplains.[72] Vegetation varied from river-lining forests of conifers, tree ferns, and ferns, to fern savannas with rare trees.[73]
Report Spam
Logged
Moonfire
Superhero Member
Posts: 1120
Re: Allosaurus
«
Reply #36
on:
December 13, 2009, 02:30:37 am »
The Morrison Formation has been a rich fossil hunting ground, holding fossils of green algae, fungi, mosses, horsetails, ferns, cycads, ginkgoes, and several families of conifers. Other fossils discovered include bivalves, snails, ray-finned fishes, frogs, salamanders, turtles, sphenodonts, lizards, terrestrial and aquatic crocodylomorphans, several species of pterosaur, numerous dinosaur species, and early mammals such as docodonts, multituberculates, symmetrodonts, and triconodonts. Such dinosaurs as the theropods Ceratosaurus, Ornitholestes, and Torvosaurus, the sauropods Apatosaurus, Brachiosaurus, Camarasaurus, and Diplodocus, and the ornithischians Camptosaurus, Dryosaurus, and Stegosaurus are known from the Morrison.[74] The Late Jurassic formations of Portugal where Allosaurus is present are interpreted as having been similar to the Morrison but with a stronger marine influence. Many of the dinosaurs of the Morrison Formation are the same genera as those seen in Portuguese rocks (mainly Allosaurus, Ceratosaurus, Torvosaurus, and Apatosaurus), or have a close counterpart (Brachiosaurus and Lusotitan, Camptosaurus and Draconyx).[75]
Report Spam
Logged
Moonfire
Superhero Member
Posts: 1120
Re: Allosaurus
«
Reply #37
on:
December 13, 2009, 02:31:00 am »
Allosaurus coexisted with fellow large theropods Ceratosaurus and Torvosaurus in both the United States and Portugal,[75] The three appear to have had different ecological niches, based on anatomy and the location of fossils. Ceratosaurs and torvosaurs may have preferred to be active around waterways, and had lower, thinner bodies that would have given them an advantage in forest and underbrush terrains, whereas allosaurs were more compact, with longer legs, faster but less maneuverable, and seem to have preferred dry floodplains.[76] Ceratosaurus, better known than Torvosaurus, differed noticeably from Allosaurus in functional anatomy by having a taller, narrower skull with large, broad teeth.[42] Allosaurus was itself a potential food item to other carnivores, as illustrated by an Allosaurus pubic foot marked by the teeth of another theropod, probably Ceratosaurus or Torvosaurus. The location of the bone in the body (along the bottom margin of the torso and partially shielded by the legs), and the fact that it was among the most massive in the skeleton, indicates that the Allosaurus was being scavenged.[77]
Report Spam
Logged
Moonfire
Superhero Member
Posts: 1120
Re: Allosaurus
«
Reply #38
on:
December 13, 2009, 02:31:42 am »
Locations in the Morrison Formation (yellow) where Allosaurus remains have been found.
Report Spam
Logged
Moonfire
Superhero Member
Posts: 1120
Re: Allosaurus
«
Reply #39
on:
December 13, 2009, 02:32:29 am »
Outcrop of the Brushy Basin Member of the Morrison Formation, west of Green River, Utah, on the Colorado Plateau.
Report Spam
Logged
Moonfire
Superhero Member
Posts: 1120
Re: Allosaurus
«
Reply #40
on:
December 13, 2009, 02:33:17 am »
Paleobiology
Life history
The wealth of Allosaurus fossils, from nearly all ages of individuals, allows scientists to study how the animal grew and how long its lifespan may have been. Remains may reach as far back in the lifespan as eggs—crushed eggs from Colorado have been suggested as those of Allosaurus.[1] Based on histological analysis of limb bones, the upper age limit for Allosaurus is estimated at 22 to 28 years, which is comparable to that of other large theropods like Tyrannosaurus. From the same analysis, its maximum growth appears to have been at age 15, with an estimated growth rate of about 150 kilograms (330 lb) per year.[47]
Report Spam
Logged
Moonfire
Superhero Member
Posts: 1120
Re: Allosaurus
«
Reply #41
on:
December 13, 2009, 02:33:55 am »
Medullary bone tissue, also found in dinosaurs as diverse as Tyrannosaurus and Tenontosaurus, has been found in at least one Allosaurus specimen, a shin bone from the Cleveland-Lloyd Quarry. Today, this bone tissue is only formed in female birds that are laying eggs, as it is used to supply calcium to shells. Its presence in the Allosaurus individual establishes sex and shows she had reached reproductive age. By counting growth lines, it was shown that she was 10 years old at death, so sexual maturity in Allosaurus was attained well before maximum growth and size.[78]
Report Spam
Logged
Moonfire
Superhero Member
Posts: 1120
Re: Allosaurus
«
Reply #42
on:
December 13, 2009, 02:34:16 am »
The discovery of a juvenile specimen with a nearly complete hindlimb shows that the legs were relatively longer in juveniles, and the lower segments of the leg (shin and foot) were relatively longer than the thigh. These differences suggest that younger Allosaurus were faster and had different hunting strategies than adults, perhaps chasing small prey as juveniles, then becoming ambush hunters of large prey upon adulthood.[48] The thigh bone became thicker and wider during growth, and the cross-section less circular, as muscle attachments shifted, muscles became shorter, and the growth of the leg slowed. These changes imply that juvenile legs has less predictable stresses compared with adults, which would have moved with more regular forward progression.[79]
Report Spam
Logged
Moonfire
Superhero Member
Posts: 1120
Re: Allosaurus
«
Reply #43
on:
December 13, 2009, 02:35:00 am »
Mounted cast of a juvenile specimen, A. "jimmadseni", North American Museum of Ancient Life
Report Spam
Logged
Moonfire
Superhero Member
Posts: 1120
Re: Allosaurus
«
Reply #44
on:
December 13, 2009, 02:35:29 am »
Feeding
Paleontologists accept Allosaurus as an active predator of large animals. Sauropods seem to be likely candidates as both live prey and as objects of scavenging, based on the presence of scrapings on sauropod bones fitting allosaur teeth well and the presence of shed allosaur teeth with sauropod bones.[80] There is dramatic evidence for allosaur attacks on Stegosaurus, including an Allosaurus tail vertebra with a partially healed puncture wound that fits a Stegosaurus tail spike, and a Stegosaurus neck plate with a U-shaped wound that correlates well with an Allosaurus snout.[81] However, as Gregory Paul noted in 1988, Allosaurus was probably not a predator of fully grown sauropods, unless it hunted in packs, as it had a modestly sized skull and relatively small teeth, and was greatly outweighed by contemporaneous sauropods.[8] Another possibility is that it preferred to hunt juveniles instead of fully grown adults.[5][61] Research in the 1990s and 2000s may have found other solutions to this question. Robert T. Bakker, comparing Allosaurus to Cenozoic sabre-toothed carnivorous mammals, found similar adaptations, such as a reduction of jaw muscles and increase in neck muscles, and the ability to open the jaws extremely wide. Although Allosaurus did not have sabre teeth, Bakker suggested another mode of attack that would have used such neck and jaw adaptations: the short teeth in effect became small serrations on a saw-like cutting edge running the length of the upper jaw, which would have been driven into prey. This type of jaw would permit slashing attacks against much larger prey, with the goal of weakening the victim.[50]
Report Spam
Logged
Pages:
1
2
[
3
]
4
Go Up
Print
« previous
next »
Jump to:
Please select a destination:
-----------------------------
Atlantis Online - Messages
-----------------------------
=> Messages
=> Administrative Messages
=> Commemorating Dates in History
=> Alerts & Warnings
=> Upcoming Events, Releases & Ads
=> Television: Shows & Events
-----------------------------
the Coffee Shop
-----------------------------
=> the Coffee Shop
=> Atlantis: Polls & News
=> Poltical Alerts
=> Causes & Activism
-----------------------------
Videos, Documentaries & Online Movies
-----------------------------
=> Ancient History & Lost Civilizations
=> Ghosts, UFOs & the Esoteric
=> Music, Entertainment & the Arts
=> Conspiracies & Suppressed Knowledge
=> Documentary & Videos
-----------------------------
Ages of the Earth
-----------------------------
=> The Early Earth, Geology & Fossils
=> Dinosaurs
=> Catastrophes & Mass Extinctions
=> Ice Age
=> Humanity's Origins & Civilization's First Steps
-----------------------------
Mythology & Heroic Sagas of Culture & Myth
-----------------------------
=> Mythology
=> Greek Mythology
=> Arthurian Myth
=> Quest for King Arthur
-----------------------------
Atlantis
-----------------------------
=> Atlantis & the Atlantic Ocean
=> Atlantis: Theories & Speculation
=> Plato's Atlantis
=> the Scientific Atlantis
=> Geology & Atlantis
=> Atlantis & the New Age
=> Atlantis in the Media
-----------------------------
Satellite Discoveries & Alternate Archaeology
-----------------------------
=> Alternate Archaeology
=> Satellite Discoveries & Aerial Archaeology
=> the Bock Saga
-----------------------------
Maps, Explorers & Adventurers
-----------------------------
=> the Oceans
=> Islands
=> the Bahamas, Bermuda, Cuba & the West Indies
=> Explorers & Adventurers
=> Maps, Cartographers & Cartography
-----------------------------
Egypt & the Pyramids
-----------------------------
=> Gods of Egypt
=> Egypt & the Pyramids
=> the Giza Complex
=> the Dynasties of Egypt
=> Egypt: Latest Discoveries
-----------------------------
the Guanches, Basques, Berbers & Sea People
-----------------------------
=> Guanches, Basques & Berbers
=> Pirates, Phantom Islands & Stories of the Sea
=> the Sea People
-----------------------------
the Ancient World
-----------------------------
=> Neolithic Europe
=> Stonehenge & the Druids
=> the Library of Alexandria, Ancient Historians & Philosophers
=> Ancient Warfare
=> the Spartans
-----------------------------
the Dawn of Civilization
-----------------------------
=> Africa, the Cradle of Life
=> China & the Asian Empires
=> Eastern Mysticism, India, & the Ancient Far East
=> Zoroastrianism, Arabia & the Near East
=> the Sumerians
=> Ancient Asia Minor
=> Hawaii, Australia, Alaska & the Pacific Rim
-----------------------------
Ancient Mediterranean Cultures
-----------------------------
=> Minoan Crete
=> Phoenicians & Carthage
=> Mediterranean Islands
=> Israelities & the Kabbalah
=> Etruscans
=> Ancient Greece
=> Rome: Empire & Republic
-----------------------------
Ancient European Cultures
-----------------------------
=> The Picts & Celts
=> Ireland: History & Myths
=> Balkan History
=> Italy & Magna Graecia
=> the Vikings & Scandinavia
=> Germanic History
-----------------------------
Timelines of Ancient Europe
-----------------------------
=> History of Britain
=> Scotland: in History & Lore
=> Continental Europe: Past & Present
=> the Dark Ages
=> the Medieval World
=> The Renaissance
-----------------------------
the Ancient Americas
-----------------------------
=> the Ancient Americas
=> Peru: Mysteries & Prehistory
=> Mesoamerican & South American Cultures
===> Aztec
===> Incan
===> Olmec
===> Toltec & Teotihuacan
=> Mayan
=> Native American
=> Canada: Past & Present
-----------------------------
The Crusades, Templars & the Holy Grail
-----------------------------
=> the Crusades
=> the Knights Templar
=> The Holy Grail & Christian artifacts
=> The Sacred Feminine, the Cathars & Gnosticism
=> the Da Vinci Code
-----------------------------
Ancient Mysteries
-----------------------------
=> Philosophy
=> Ancient Mysteries
=> Lemuria, Mu & other sunken civilizations
=> Easter Island
=> Oak Island
-----------------------------
Archaeology & Anthropology
-----------------------------
=> Museums & Universities
=> Archaeology
=> Ancient Languages
=> Archaeological News
=> Underwater Archaeology
-----------------------------
Ancient Knowledge, Mysticism & Sacred Beliefs
-----------------------------
=> Ley Lines, Ancient Astronomy & Archeoastronomy
=> Prophecy, 2012, End Times & the End of the World
=> Sacred Symbols
=> The Ancient Arts: Astrology, Alchemy, the Tarot, Arcane Recondite Practices & the I Ching
-----------------------------
Search for the Sacred
-----------------------------
=> Angels & Angelology
=> Goddess Worship
=> Search for the Sacred
=> World Religions
=> the Urantia Book
=> Wicca, Witchcraft, Paganism & Ritual Magic
-----------------------------
Health & Healing
-----------------------------
=> Health, Healing & Medical News
=> Human Biology
=> Love & Relationships
=> Women's Studies
-----------------------------
Science & Technology
-----------------------------
=> Science, Physics & Technology
=> History of Science
=> Evolution vs. Intelligent Design
=> Human Genetics
-----------------------------
Earth Changes
-----------------------------
=> Earth Changes
=> Global Warming
=> Botany & Plant Life
===> Plants of the Americas that Changed the World
=> Antarctica & the Arctic
-----------------------------
Space
-----------------------------
=> NASA
=> Mars, the Red Planet
=> Life on Other Worlds
=> the Universe
=> Images from Space
-----------------------------
UFOs, Aliens & Future Science
-----------------------------
=> UFO's
=> Aliens & Alien Abduction
=> UFO Evidence & in the Media
=> Alternate History & Multiverses
=> Future Science
=> Time Travel
-----------------------------
the Occult
-----------------------------
=> Ghosts & Apparitions
=> Communicating with the Dead
=> Paranormal Events, Reincarnation & Near Death Experiences
=> the Enchanted World
=> the Supernatural
=> the Occult
-----------------------------
the Unexplained
-----------------------------
=> Cryptozoology
=> Bigfoot Sightings
=> the Unexplained
=> the Hollow Earth, Crop Circles, Strange Structures & Devices
=> Vanishings & Unsolved Murders
-----------------------------
Science Fiction & Fantasy
-----------------------------
=> Lord of the Rings
=> Science Fiction
=> King Kong, Gigantopithecus & the Mountain Gorilla
=> Godzilla, King of Monsters
=> Comic Books
===> Comic Book Creators
===> Videogames & Toys
-----------------------------
Halloween & Seasonal
-----------------------------
=> Halloween
=> Seasonal
=> Monsters of Myth, Movies & Folklore
=> Ghost Stories
=> the Zombie Apocalypse
-----------------------------
Genres of Film & Literature
-----------------------------
=> Universal Horror
=> H. P. Lovecraft
=> Horror
=> Dark Shadows
=> Twin Peaks
=> Online Horror Movies Sci-Fi & TV Series
-----------------------------
Arts & Literature
-----------------------------
=> Online Books & Research Papers
=> Classical Literature & Book Reviews
=> Art History
=> Architecture
=> Sculpture & Statuary
=> the Great Masters
=> Music
-----------------------------
Media & Film
-----------------------------
=> Cinema
=> the History of Film
=> Marilyn Monroe
=> Actresses & Models
=> Entertainment News
-----------------------------
Modern Historical Mysteries
-----------------------------
=> American History
===> Presidents of the United States
=> the World Wars
===> the Great Depression
=> the Holocaust
=> the Middle East: Past & Present
=> Modern History
===> the Industrial Age
===> Civil Rights
=> Great Cities of the World
=> the Kennedys: Their History & Assasinations
=> New York City: Then & Now
-----------------------------
September 11th, 2001
-----------------------------
=> September 11th: Conspiracies, Cover-ups & Remembrance
=> The World Trade Center Remembered
===> Life of the Twin Towers
=> Modern Warfare
=> Environmental Disasters & Mass Tragedies
-----------------------------
Suppressed Knowledge
-----------------------------
=> New World Order
=> Conspiracies
=> Suppressed Knowledge
=> Media Matters
-----------------------------
Politics
-----------------------------
=> the Barack Obama Administration
=> Conservatives, Trump, & Republican Politics
=> Joe Biden, Democratic Politics & News
=> Tea Party, Constitution, Libertarian Parties & Ron Paul
=> Politics & News
-----------------------------
Current Events
-----------------------------
=> Current Events & Odd Stories
=> The World Today
=> Financial News & the Economy
===> The History of Labor
=> Breaking News
-----------------------------
General Category
-----------------------------
=> Opinions & Editorials
=> Cartoons, Humor & Comic Strips
=> Ecology, Pets & the Animal Kingdom
=> General & Miscellaneous
=> Sports
=> Computers & the Internet
-----------------------------
Art, Graphics & Creative Writing
-----------------------------
=> Fantasy Art & Graphics
=> Creative Writing
===> Horror Fiction
=> Poetry
=> Photography & Models
=> Earth Images
-----------------------------
Past Events
-----------------------------
=> Case for Bush Impeachment/War Crimes
===> Bush Administration Torture Scandal
=> Campaign 2008
=> Atlantis Online - Memorial & Biography
===> Atlantis Online - Old Posts
Powered by
EzPortal
Loading...