| Creodonta Fossil range: Late Paleocene to Late Miocene |
||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
 Hyaenodon gigas and H. The Paleocene or Palaeocene, "early dawn of the recent" is a geologic epoch that lasted from 65 The Miocene is a geological epoch of the Neogene period and extends from about 23 Hyaenodon (" Hyaena -toothed" is an extinct Genus of Hyaenodonts, a group of Creodonts Some Species mongoliensis
|
||||||||||||
| Scientific classification | ||||||||||||
|
||||||||||||
| Families | ||||||||||||
The creodonts are an extinct order of mammals that lived from the Paleocene to the Miocene epochs. Chordates ( Phylum Chordata) are a group of Animals that includes the Vertebrates together with several closely related Invertebrates Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands See also Evolution of mammals Eutheria ("true beast" are a group of Mammals consisting of Placental mammals plus all extinct Mammals Laurasiatheria is a Clade of rank Cohort or super-order within the Placentalia (living or Eutheria (Placentals and their extinct ancestors Edward Drinker Cope (July 28 1840&ndashApril 12 1897 was an American paleontologist and comparative anatomist, as well as a noted herpetologist In Biological classification, family ( Latin Hyaenodontidae (" Hyena teeth" is a family of the extinct order Creodonta, which contains several dozen genera. Oxyaenidae is a family of the extinct order Creodonta; it contains three subfamilies comprising ten genera In Biology and Ecology, extinction is the cessation of existence of a Species or group of taxa. This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands The Paleocene or Palaeocene, "early dawn of the recent" is a geologic epoch that lasted from 65 The Miocene is a geological epoch of the Neogene period and extends from about 23 They shared a common ancestor with carnivorans. The diverse order Carnivora (kɑrˈnɪvərə or sometimes /ˌkɑrnɪˈvɔərə/ from Latin carō (stem carn-) "flesh" + vorāre
Creodonts were an important group of carnivorous mammals from 55 to 35 million years ago in the ecosystems of Africa, Eurasia and North America. For the superstate in George Orwell 's novel see Nations of Nineteen Eighty-Four. In Oligocene Africa, they were the dominant predatory group. The Oligocene is a geologic epoch of the Paleogene period and extends from about 33 They competed with the Mesonychids, and the Entelodonts and ultimately outlasted them by the start of the Oligocene and by the middle of the Miocene respectively, but lost ground to the Carnivorans. Mesonychia ("Middle Claws quot are an extinct order of medium to large-sized carnivorous mammals that were closely related to Artiodactyls (even-toed Entelodonts are an extinct Omnivorous, group of Mammals distantly related to modern Pigs and other non- ruminating Artiodactyls They The Miocene is a geological epoch of the Neogene period and extends from about 23 The diverse order Carnivora (kɑrˈnɪvərə or sometimes /ˌkɑrnɪˈvɔərə/ from Latin carō (stem carn-) "flesh" + vorāre The last genus went extinct 8 MYA, and carnivorans now occupy their ecological niches.
Contents |
Evolution and taxonomy
Creodonts were considered ancestors to Carnivora, but are now considered to have shared a common ancestor further back. The diverse order Carnivora (kɑrˈnɪvərə or sometimes /ˌkɑrnɪˈvɔərə/ from Latin carō (stem carn-) "flesh" + vorāre They share with the Carnivora the carnassial shear, scissor teeth that evolved to slice meat and gave both orders the tools to dominate the niche. Carnassials are large teeth found in many Carnivorous Mammals, used for shearing flesh and bone in a Scissor or Shear -like way In Ecology, a niche (pronounced nich nēsh or nish A shorthand definition of niche is how an organism makes a living Some researchers argue that the creodonts represent a group of mammals of diverse biological ancestry that resemble one another via convergent evolution, rather than being the descendants of a single common ancestor. Convergent evolution describes the acquisition of the same biological trait in unrelated lineages Their origins lie at least as far back as the late Cretaceous, though they did not radiate much until the Cenozoic. The Cretaceous (kriːˈteɪʃəs, usually abbreviated 'K' for its German translation "Kreide" is a geologic period and system, reaching from the end of An adaptive radiation is a rapid Evolutionary radiation characterized by an increase in the morphological and ecological diversity of a single rapidly diversifying lineage The Cenozoic (also Caenozoic or Cainozoic) Era (ˌsiːnəˈzoʊɪk/ /ˌsɛn- (meaning "new life" ( Greek ( kainos) "new" [1] Creodonts were the dominant carnivorous mammals from 55 to 35 MYA, peaking in diversity and prevalence during the Eocene. In Astronomy, Geology, and Paleontology, mya or " mya " is an abbreviation for "million years ago". The Eocene epoch (558 ± 02 - 339 ± 01 Ma) is a major division of the Geologic timescale and the second epoch of the Palaeogene period in [2] By the mid Oligocene, Creodonts supplanted both the Mesonychids, and giant flightless predatory birds entirely in North America, Eurasia and Africa, and in turn, competed with their own relatives Carnivorans. The Oligocene is a geologic epoch of the Paleogene period and extends from about 33 Mesonychia ("Middle Claws quot are an extinct order of medium to large-sized carnivorous mammals that were closely related to Artiodactyls (even-toed Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. For the superstate in George Orwell 's novel see Nations of Nineteen Eighty-Four. The last genus, Dissopsalis, went extinct about eight million years ago. Dissopsalis is a genus of extinct predatory Mammals of the order Creodonta.
Habitat
The creodonts ranged across North America, Eurasia and Africa, in forms that resemble those of modern carnivores. For the superstate in George Orwell 's novel see Nations of Nineteen Eighty-Four. Amongst their number was Megistotherium, which some argue was the largest mammalian land predator of all time, the size of a bison and with a skull twice as big as a tiger's. Megistotherium osteothlastes (from Greek Megistos "Greatest" + Therios "Beast" was an enormous hyaenodontid creodont This is an article about an animal For other uses see Bison (disambiguation. Megistotherium may have rivaled Andrewsarchus mongoliensis in size. Andrewsarchus mongoliensis (pronounced ANN-drew-SARK-us ( Andrews + Greek ἀρχός, "ruler" was a basal, heavily-built Their dominance over the early Carnivora, known as miacids, began to wane after 35 MYA. The miacids (Miacidae were primitive Carnivores which lived during the Paleocene and Eocene Epoch about 65 - 33 million years ago The creodonts survived until 8 million years ago; the last form, Dissopsalis, died out in Pakistan. Dissopsalis is a genus of extinct predatory Mammals of the order Creodonta. Pakistan () officially the Islamic Republic of Pakistan, is a country located in South Asia, Southwest Asia, Middle East and Bears, cats, mustelids, hyenas, canids such as wolves and other Carnivora now occupy the former creodont niches. WikipediaManual of Style (spelling, articles should conform to one overall spelling style of English typically the one most linked to the article topic (if it is geographic Mustelidae or Mustelids (from Latin mustela, Weasel) commonly referred to as the weasel family, is a family of carnivorous Mammals The Hyaenidae is a Mammalian family of order Carnivora. The Hyaenidae family native to both African and Asian continents consists of four The Canidae (ˈkænədiː ′kanə′dē family is a part of the order Carnivora within the Mammals (Class Mammalia The grey wolf or gray wolf ( Canis lupus) also known as the timber wolf or simply wolf, is a Mammal of the order Carnivora
Reasons for extinction
It is not known exactly why the Creodonts were replaced by Carnivora. It may be because of their smaller brains and locomotion which was somewhat less energy-efficient (especially while running) and mostly plantigrade. In Biomechanics, animal locomotion is the study of how Animals move. In Mammals, plantigrade locomotion means walking with the podials and Metatarsals flat on the ground [3] These subtle disadvantages may have been important over millions of years. The Creodont lumbosacral spine was not arranged as efficiently for running as in Carnivora. The arrangement of the teeth was also somewhat different. In the miacids (and so in the modern Carnivora), the last upper premolar and the first lower molar are the carnassials, allowing grinding teeth to be retained behind for feeding on non-meat foods (the Canidae are the closest modern analog to miacid dentition). Molars are the rearmost and most complicated kind of Tooth in most Mammals In many mammals they grind food hence the Latin name mola, " Millstone Carnassials are large teeth found in many Carnivorous Mammals, used for shearing flesh and bone in a Scissor or Shear -like way The Canidae (ˈkænədiː ′kanə′dē family is a part of the order Carnivora within the Mammals (Class Mammalia In creodonts, the carnassials were further back - either first upper and second lower molars, or second upper and third lower molars. This committed them to eating meat almost exclusively.
In the most strictly carnivorous of modern Carnivora, the Felidae, the second and third molars have disappeared completely, and the first upper molars behind the carnassials have become vestigial. Felidae is the biological family of the cats a member of this family is called a felid. Vestigiality describes homologous characters of Organisms which have lost all or most of their original function in a species through Modern cats thus eat plant food only incidentally.
References
- The Velvet Claw: A Natural History of the Carnivores, David Macdonald, BBC Books, ISBN 0-563-20844-9
- David Lambert and the Diagram Group. The Field Guide to Prehistoric Life. New York: Facts on File Publications, 1985. ISBN 0-8160-1125-7
Footnotes
- ^ Lambert, 162
- ^ Lambert, 162
- ^ The Elements of Geology. Globusz. Retrieved on March 11 2008.
Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic