Guest guest Posted September 12, 2009 Report Share Posted September 12, 2009 I posted: > > Like elephants, cheetahs evolved first in > > North America, and were in Asia before they reached Africa. posted: > > (This claim has been disputed. The Wikipedia entry on Cheetah >reads the following : >It probably evolved in Africa during the Miocene epoch (26 >million to 7.5 million years ago), before migrating to Asia. New >research by a team led by Warren Johnson and Stephen O'Brien of the >Laboratory of Genomic Diversity (National Cancer Institute in >Frederick, Maryland, United States) has recently placed the last >common ancestor of all existing species as living in Asia 11 million >years ago, which may lead to revision and refinement of existing >ideas about cheetah evolution. Johnson seems to have come down on both sides of the issue; see below, also from Wikkepedia: Miracinonyx (American cheetahs) is an extinct genus of the family Felidae, endemic to North America during the Early Pliocene epoch (1.8 mya-11,000 years ago), existing for approximately 1.789 million years.[1] There were at least two species of feline, morphologically similar to the modern cheetah. Living from three million to ten or twenty thousand years ago in North America, these cats are known only from fragments of skeletons. Two species have been identified: Miracinonyx inexpectatus and M. trumani. Sometimes a third species, M. studeri, is added to the list, but it is more often listed as a junior synonym of M. trumani. Both species are similar to the modern cheetah, with faces shortened and nasal cavities expanded for increased oxygen capacity, and legs proportioned for swift running. However, these similarities are not inherited from a common ancestor, but result from parallel evolution. Contents [hide] * 1 Taxonomy and evolution * 2 Miracinonyx trumani * 3 Miracinonyx inexpectatus * 4 References * 5 External links [edit] Taxonomy and evolution Research into the American cheetah has been contradictory. It was originally believed to be an early cougar representative, before being reclassified in the 1970s as a close relative of the cheetah.[2] This suggested that ancestors of the cheetah diverged from the Puma lineage in the Americas and migrated back to the Old World, a claim repeated as recently as Johnson et al. (2006).[3] Other research by Barnett, however, examining mitochondrial DNA and re-analyzing morphology, has suggested reversing the reclassification: the American cheetah developed cheetah-like characteristics through convergent evolution, but it is most closely related to Puma and not to the modern cheetah of Africa and Asia.[4] The supposed American origin of the modern cheetah is thus equivocal; however, it is believed to have evolved from cougar-like ancestors, whether in the Old or New World. The cougar and M. trumani are believed to have split from a cougar-like ancestor around three million years ago;[4] where M. inexpectatus fits in is unclear, although it likely is a more primitive version of M. trumani.[5] -- Merritt Clifton Editor, ANIMAL PEOPLE P.O. Box 960 Clinton, WA 98236 Telephone: 360-579-2505 Fax: 360-579-2575 E-mail: anmlpepl Web: www.animalpeoplenews.org [ANIMAL PEOPLE is the leading independent newspaper providing original investigative coverage of animal protection worldwide, founded in 1992. Our readership of 30,000-plus includes the decision-makers at more than 10,000 animal protection organizations. We have no alignment or affiliation with any other entity. $24/year; for free sample, send address.] Quote Link to comment Share on other sites More sharing options...
Guest guest Posted September 12, 2009 Report Share Posted September 12, 2009 This discussion highlights the rather confusing nature of evolutionary and taxonomic research. A paper entitled " A primitive Late Pliocene cheetah, and evolution of the cheetah lineage " written by Per Christiansen and Ji H. Mazák, published in the Proceedings of the National Academy of Sciences in USA in January, 2009 makes the following claim : " The cheetah lineage is a group of large, slender, and long-limbed cats with a distinctive skull and dental morphology, of which only the extant cheetah (*Acinonyx jubatus*) is present today. The lineage is characterized by having abbreviated, tall, and domed crania, and a trenchant dentition with a much reduced, posteriorly placed protocone on the upper carnassial. In this article, we report on a new discovery of a Late Pliocene specimen from China with an estimated age of ≈2.2–2.5 million years, making it one of the oldest specimens known to date. A cladistic analysis confirmed that it is the most primitive cheetah known, and it shares a number of unambiguous derived cranial traits with the *Acinonyx* lineage, but has more primitive dentition than previously known cheetahs, demonstrating that the many unusual skull and dental characters hitherto considered characteristic of cheetahs evolved in a gradual fashion. Isolated teeth of primitive cheetahs may not be recognizable as such, but can be confused with, for instance, those of leopards or other similar-sized pantherine cats or pumas. The age and morphology of the new specimen supports an Old World origin of the cheetah lineage, not a New World one, as has been suggested. We name the new species *Acinonyx kurteni* in honor of the late Björn Kurtén. " and goes on to say : " Although our analysis of craniodental characters favors one evolutionary lineage of cheetah-like cats, and indicates a close relationship of * Miracinonyx*, at least *M. trumani*, to *Acinonyx*, *A. kurteni* has a number of primitive traits, notably more primitive dentition, that could indicate two separate lineages, each culminating in craniodentally highly derived predators, and thus, we would not at this time entirely rule out that the highly cheetah-like morphology of *M. trumani* evolved convergently in the Americas, as suggested by ref. 27. " (Paper text here : http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2626734 ) Please note the following statement : " We name the new species *Acinonyx kurteni* in honor of the late Björn Kurtén. " It lends a bit of credence to my previous posting that stated : " This also gives rise to the cardinal question : how do we define a species and categorise a subspecies and a race? Some of the distinctions have been quite arbitrary, guided by personal motives of scientists and aided by desires of conservationists. I am quite eager to know if the proposed Cheetah project is moving toward that direction. " If one has the right kind of connections, it is not inconceivable that a Cheetah species could be named as Acinonyx merritt cliftonii or Acinonyx shubhobroto ghoshii. On 9/12/09, Merritt Clifton <anmlpepl wrote: > > I posted: > > > > > Like elephants, cheetahs evolved first in > > > North America, and were in Asia before they reached Africa. > > > > > > posted: > > > > > > (This claim has been disputed. The Wikipedia entry on Cheetah reads the > following : > > It probably evolved in Africa during the Miocene epoch (26 > > million to 7.5 million years ago), before migrating to Asia. New research > by a team led by Warren Johnson and Stephen O'Brien of the Laboratory of > Genomic Diversity (National Cancer Institute in Frederick, Maryland, United > States) has recently placed the last common ancestor of all existing species > as living in Asia 11 million years ago, which may lead to revision and > refinement of existing ideas about cheetah evolution. > > > > > > Johnson seems to have come down on both sides of the issue; see > below, also from Wikkepedia: > > > > > > *Miracinonyx* (American cheetahs) is an extinct genus of the family > Felidae, endemic to North America during the Early Pliocene epoch (1.8 mya-11,000 > years ago), existing for approximately 1.789 million years.[1] > There were at least two species of feline, morphologically similar to the > modern cheetah. Living from three million to ten or twenty thousand years > ago in North America, these cats are known only from fragments of > skeletons. > Two species have been identified: Miracinonyx inexpectatus and M. trumani. > Sometimes a third species, M. studeri, is added to the list, but it is more > often listed as a junior synonym of M. trumani. Both species are similar to > the modern cheetah, with faces shortened and nasal cavities expanded for > increased oxygen capacity, and legs proportioned for swift running. However, > these similarities are not inherited from a common ancestor, but result fromparallel evolution > . > *Contents* [hide] > * 1 Taxonomy and evolution > * 2 Miracinonyx trumani > * 3 Miracinonyx inexpectatus > * 4 References > * 5 External links > > [edit] > Taxonomy and evolution > Research into the American cheetah has been contradictory. It was > originally believed to be an early cougar representative, before being > reclassified in the 1970s as a close relative of the cheetah.[2] This > suggested that ancestors of the cheetah diverged from the Puma lineage in > the Americas and migrated back to the Old World, a claim repeated as > recently as Johnson et al. (2006).[3] Other research by Barnett, however, > examining mitochondrial DNA and re-analyzing morphology, has suggested > reversing the reclassification: the American cheetah developed cheetah-like > characteristics through convergent evolution, but it is most closely > related to Puma and not to the modern cheetah of Africa and Asia.[4] The > supposed American origin of the modern cheetah is thus equivocal; however, > it is believed to have evolved from cougar-like ancestors, whether in the > Old or New World. > The cougar and M. trumani are believed to have split from a cougar-like > ancestor around three million years ago;[4] where M. inexpectatus fits in > is unclear, although it likely is a more primitive version of M. trumani. > [5] > > > > -- > > Merritt Clifton > Editor, ANIMAL PEOPLE > P.O. Box 960 > Clinton, WA 98236 > > Telephone: 360-579-2505 > Fax: 360-579-2575 > E-mail: anmlpepl > Web: www.animalpeoplenews.org > > [ANIMAL PEOPLE is the leading independent newspaper providing original > investigative coverage of animal protection worldwide, founded in 1992. > Our readership of 30,000-plus includes the decision-makers at more than > 10,000 animal protection organizations. We have no alignment or affiliation > with any other entity. $24/year; for free sample, send address.] > Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You are posting as a guest. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.