prehistoric size estimates

[dyno77]

so over the years iv noticed that weight and length estimates of dinosaurs mostly have been so varied that its ridiculous. It not a huge deal but brachiosaurus used to weight 75tons in the 1980s and then it shrunk to 45 in the early 2000s and then again to 25,less than half its original weight but recently newer calculations increased it by a few tons. But whats so annoying is that the mainstream headlines such as triceratops never existed and dinosaurs have shrunk in size by 50% doesn't do them justice and thats my view as a longtime prehistoric fan ....

Now its not just dinosaurs that get reduced in size but also certain prehistoric beasts such as deinosuchus and gigantopithecus ,among a select few others which get targeted mostly because of lack of fossils but in deinosuchus case it has more fossils now showing it was indeed a giant and not some crocodile form barley larger than the nile crocodile...
even megalania was reduced by some experts by a size so low that it sounded ridiculous..not for once would i buy that it was barley larger than the monitor lizard...but this was in the early 2000s and pretty much no experts buys that low estimate and never did to begin with....
Gigantopithecus ,more recently has been shrunk in size to barley 6ft high and 200kg which is barley the size of a large gorilla species .This will be different from the other downgrades in size because i really doubt any half skeletons will ever be found because it seems to be more elusive,than any other prehistoric beast .unlike the downgrading to pliosaurs,megalodon,quetzalcoatlus ,various dinosaurs,and so on,but iv seen no official reports on the downgrading to gigantopithecus,just a select few claims made by a select few experts...where as the others had many official articles that laid out how and why and the evidence to back the new estimates,and in only barley just seen a few reports pushed away to the side on gigantopithecus new size and nothing else...no diagrams and explanations of why and how they reduced it,and the evidence to show why,nothing ...that in my view is the same biased experts that shrunk deinosuchus to the size of a nile crocodile only because they didn't consult the lead expert on deinosuchus that would've showed them the larger skull fragments ,point is all im asking for is the evidence to show why its the size they claim ,simple as that ...

[dyno77]

Another thing is a do read the articles esp when they come from the lead experts on dinosaurs,but when some average journalist or average fossil degree first year makes claims based on nothing but biased viewpoints then it should be taken with a grain of salt and ,as a longtime prehistoric collector and fan that should be the standard,not the exception..
For example the claims of triceratops being torosaurus  is stupid ,even though i haven't got access to the fossils or anything like that iv read enough and seen photos of young torosaurus skulls and huge adult triceratops skulls which are on par with the largest torosaurus...why horner and scanella wouldn't consider or even include these skulls is beyond me. This shows they are biased ,even though they are right about pretty much anything else regarding triceratops and torosaurus..triceratops growth is amazing,but it isn't torosaurus and even i knew that long ago,long before the report....

[Papi-Anon]

Gigantopitgecus's 'shrinking' is attributed to the fact that as a distant cousin to the orangutan it was first estimated in size (G. Blacki, specifically) based on teeth and an incomplete lower jaw in a body scaled up from a modern orangutan to fit those bones' sizes. Problem is that orangutans are arboreal and Giganto was more than likely NOT climbing through the trees due to its size even at the lower estimates. Since it ate and lived like modern gorillas did the revised body plan has instead been scaled on a gorilla-build instead, and given the robustness of gorillas that would clock Giganto in at least modern gorilla size if not a little bigger. A lot of fragmentary remains of megafauna got overestimated in the past for numerous reasons (sensationalism primarily), plus understanding biology better nowadays we can give more accurate estimations on size and weight. Recently Paleoloxodon supplanted Paraceratherium as the largest terrestrial mammal due to calculated musclature of the two.

[andrewsaurus rex]

dinosaurs 'shrinking' in size is really not that surprising.   In the early days of dino digging, techniques were not as sophisticated as they are today for size/weight estimates.  That plus there being a BIG advantage in 'exaggerating' sizes (more headlines, more funding) and you can easily see why it would happen.

Plus many of the animals were less well known from fossil evidence back in the early days, so a lot of guess work had to be used to fill in the holes in the skeletal remains that were known.  Tails were often guessed far too long, exaggerating lengths, for example.

The media plays a role too.  When you already have a known 80 foot dinosaur, a new one discovered that is 'only' 75 feet is not worth running an article about.  But if somebody, somewhere happens to casually say it might have grown as long as 90 feet, bam.....now it's headline material and the 90 foot figure becomes accepted as the animal's size.

There are a whole host of other reasons that size estimates are usually exaggerated. eg  Is the animal being estimated with its skeletal elements all laid out in a straight line, or estimated in a natural life pose?

Modern day size/weight estimates are far better guides to prehistoric animal sizes than older estimates.  That said, they still leave a lot to be desired, especially weight estimates, which, as you pointed out, vary so much they are close to useless.

I try not to get too hung up on numbers like this any more.  Suffice to say they were big and spectacular.....no quantification necessary.