What! T. rex is not T. rex

[jkfoam]

Tyrannosaurus rex is not Tyranosaurus rex but Manospondylus gigas .  Now there is a name that is sure to fire the old imagination.  With that name I don't think Jurassic Park would have ever played the silver screen.  For more info go to

            www.visionlearning.com/library/module_viewer.php?mid=89 . 

The site is an interesting discussion on Taxonomy (naming organisms, past and present).  Personnaly I am often baffled and confused by the rules of Taxonomy.  There is more to a name than just the Genus, species.  I am also confused about the rules of speciation and genus assignments.  So much to learn.  I need more books.

JKFoam

[Gatorman]

I can't even say Manospondylus what kinda name is that?

[Silvershark]

It's a complicated issue because genus, family etc are placing animals in neat categories when nature doesn't tend top work that way.

Normally when a species has been named twice, the first name is given priority because that's the fairest system.  Recently Stethacanthus was given a new name (can't remember the new name though)   

Taxonomy is just a way to allow species to be named and place an organism into a category.  Because species names are universal (hence each species only has one species same) it makes it a lot easier to say what species is meant compared to using common names which vary considerably from place to place.  With speciation, the species will first become a sub-species say a population of Pretendus speciesus that become isolated for long enough for them to be considered different will become Pretendus speciesus subspeciesus : Genus - species - subspecies.  If the cause of speciation continues and the two become significantly different, one will become a species in it's own right and just have the single species name, Pretendus subspeciesus : Genus - species.  If the divergence continues even further to the extent where the two species are no longer closely related enough to be classed in the same genus, one will be given a new genus name (this is also occuring through the use of DNA analysis which is discovering that some species considered to be closely related aren't and others thought to be one species are actually several species/subspecies). 

[jkfoam]

Silvershark,

Thanks for that discussion.  It is informative.  In living organisms they have DNA as a tool to help in Taxonomy along with anatomical features.  In fossils we dont have that available usually.  We only have the skeleton, print, shell, etc. to differentiate the various organisms.  My question is how investigators know when divergent features are sufficient to declare a subspecies, a new species or a new genus or sub genus.   

My quandrary is magnified when I look at certain North American fossils and their European or British very close relatives.  The North American cenozoic snail "Athleta" is an example.  In England or Europe it would be called "volutilithes".  Do a Google Image search for "Athlete petrosus and Volutilithes spinosus.  I suspect at some earlier time there was some intercontinental paleontological politics going on.  Or it is just that no one capable has taken the time , energy or effort to resolve the issue.

Taxonomy is one of the things I personnaly need to study more.  It on my "To Do" list.  I just haven't taken the effort.

JKFoam

JKFoam

[Silvershark]

Ahhh okay.  With fossils the taxonomy is much more complicated and generally I think things such as genus are less focused on.  As you said, it is working from fossils not living animals and DNA.  Generally when it comes to fossils I think it tends to stick with species, not subspecies because picking out the differences between subspecies - which are often down to slight behavioural differences or habitat - isn't actually possible with just the fossils.  It is pretty much a case of something is either similar enough to be classed as the same, or different enough to be considered different.  Genus tends only to be shared by species that appear to be very closely related.  With fossils though this is just as likely (and in fact is often the case) they are just classed as one species and until looked at in detail is it shown that there are enough differences for them to be considered significantly different to be classed as a seperate species.

Looked up the two in your example, both are apparently true Genus.  Without actually knowing about the fossils and organisms though I couldn't say what could cause them to be classed seperately, the images I found on google though similar aren't undistinguisable from each other so maybe there are significant differences though since one looked considerably more weathered than the other that may be a big factor in that.  With things like shells your looking at tiny details of their structure, the sediments they were laid down in, evidence of prolonged geographical isolation.  To find the answer your best speaking to an expert on those particular shells.

[Giganotosaurus]

Manospondylus gigas was the older genus, T.rex was made up to kind of get the crowd more intressted.

Since it was a milstolpe in the dinosaurian sience, it was special and most of all BIG. It had to get a special, horrorfying name.

Of course, it can be discussed futher, but this is what i have herad/learned.

And yes, true, taxonomy is mostly just the way to keep all the generas and groups organiszed.

Greetings

Gig

[DD1991]

On 6/29/2007 at 4:10 PM, Gatorman said:

I can't even say Manospondylus what kinda name is that?

Manospondylus means "porous vertebra" in Greek. It was coined by in 1892 by Edward Drinker Cope for two fragmentary vertebrae from South Dakota that he interpreted as belonging to a ceratopsid. John Bell Hatcher in his posthumous 1907 monograph on ceratopsians recognized that Manospondylus was a theropod, and Osborn (1917) noted that AMNH 3982 was very similar to Tyrannosaurus rex. Fossils of T. rex were found at the Manospondylus type locality in June 2000, but T. rex is such a familiar name to the general public that Manospondylus gigas has become a nomen oblitum.

 

Cope, E.D., 1892. Fourth note on the Dinosauria of the Laramie. The American Naturalist 26:756-758

 

Hatcher, J. B. (1907). The Ceratopsia. Monographs of the United States Geological Survey.

 

Osborn, H. F. (1917). Skeletal adaptations of Ornitholestes, Struthiomimus, Tyrannosaurus. Bulletin of the American Museum of Natural History. 35 (43): 733–771. hdl:2246/1334.