Carnosaur
MemberCompsognathusJul-14-2014 9:34 PMDid a topic like this a while back, decided to revamp it.
Acrocanthosaurus Atokensis; The high-spined lizard
The name was first assigned to two very incomplete specimens (OMNH 10146 and OMNH 10147), discovered in the early 1940s, it consisted of two partial skeletons and a piece of skull excavated from Atoka County in Oklahoma which were finally scientifically described in 1950.
For the holotype, OMNH 10146, has been given a total body mass of roughly 3.02 tons. This is based off of the femoral length of 1170.8 mm.
However, applying the "8ths rule" to this animal, i came up with a different figure. Skull length of the holotype was 1160 mm(3.80577 feet) Basing off of Eocarcharia(another early Carcharodontosaur) i came up with a slightly highly weighet estimate.
3.80577x8 yields 30.5 feet TBL. A mass estimate of 3.5 tons was what the calculations yielded
However, this is just for the holotype. A few larger specimens have been unearthed.
An even more complete skeleton (NCSM 14345) affectionately nicknamed 'Fran' appears to be substaintially larger.
The skull alone measured 1.3 meters(4.3 feet) long. That's all we need to get an estimate for it.
4.3x8 yields 34.5 TBL. Based on the femur length of this animal(1,277mm) 'Fran" would have weighed in 5.78713 tons.
Skeletal elements of OMNH 10147 are almost the same size as comparable bones in NCSM 14345, indicating an animal of roughly the same size.
Acrocanthosaurus may be known from less complete remains outside of Oklahoma, Texas, and Wyoming. A tooth from southern Arizonahas been referred to the genus. Estimates have not been given for these remains, because teeth are unreliable in the fact we do not know what position they lay in the jaw, and teeth vary in size based on their placement.
So, basing off of the few specimens we do have of Acrocanthosaurus, a size range of 10-11.5 meters TBL and 3-5 tons seems plausible. Not the enormous 7 ton monster i've seen so estatically thrown around the internet, but this animal is certainly not one you would want to meet in a dark alley.
Nature doesn't deceive us; it is we who deceive ourselves.
Primal King
MemberCompsognathusJul-14-2014 10:20 PMSeems like sound research and plausible estimates. Good post!
"If you can't see it... It's already too late."
-Jurassic Apocalypse (by Paden)
Something Real
MemberTyrannosaurus RexJul-15-2014 12:27 AMCARNOSAUR - Acrocanthosaurus! Oh, my absolute favorite! I've been in love with this dinosaur since I was a late teen (maybe 19)! The estimates and work you've presented appear very well-thought and extensively researched; very nicely done! I agree whole-heartedly when you say that you've strong doubts in the premise that this animal weighed in at nearly seven tons - that's very likely ludicrous. However, 3-5 tons is definately possible. Of course, as much as I adore this creature, I'd certainly never want to meet one; I don't think I could run fast enough in the heels I wear to escape it, and I certainly don't think crying would disuade it from making a snack of me! Thank you ever so much for presenting this to us! :)
Jezza
MemberCompsognathusJul-15-2014 12:34 AMAs the biggest acro fan on the site, you should have expected me.
From my research I put acro at 5.5-6.7 tons and 40 ft long. You forget that acro was the bodybuilder of the sauropod killers, it also had that spine that was layered with muslce, not a spinosaur spine.
Youre fat, and I'm not sugarcoating it cause you'd probably eat that too.
UCMP 118742
MemberCompsognathusJul-15-2014 7:35 AMI completely agree.
Keep in mind that many people have died for their beliefs; it's actually quite common. The real courage is in living and suffering for what you believe in. -Brom-
Carnosaur
MemberCompsognathusJul-15-2014 8:50 AM@jezza while it may have been a sauropod killer, this most certainly wasn't the bulk of its diet. It probably fed on the ornithopods and some early hadrosaurs as a staple diet.
We also do not know if the spine was covered in muscle, for all we know id could be covered in a thin layer of skin. All we do know is that these neural spines are thicker in circumferenece then Spinosaurus', and extend further down the back.
As for the 'bodybuilder' refererence, i haven't come across anything that would suggest this. Keep in mind Allosaurus Fragilis was also thought to be a sauropod killer, and it weighed only around two tons. Acrocanthosaurus, being an early carcharodontosaur, probably would not be as heavily built as the later species(Giganotosaurus, Carcharodontosaurus, perhaps even tyrannotitan). Acro was kind of the prototype if you will, a stepping stone in the evolution of the sauropod hunters.
Nature doesn't deceive us; it is we who deceive ourselves.
Sci-Fi King25
MemberAllosaurusJul-15-2014 8:51 AMThese are some great estimations! Are you going to do more size estimations for different dinosaurs?
“Banana oil.”- George Takei, Gigantis: The Fire Monster
Carnosaur
MemberCompsognathusJul-15-2014 9:23 AMyes, i plan on doing it with most dinosaur families...Among the ones i'm going to be profiling are:
Shantungosaurus Diplodocus Sauroniops
Amphicoelias Giraffititan Carcharodontosaurus
Utah Nodosaur Spinosaurus Triceratops
Utahraptor Tyrannosaurus Torvosaurus
Nature doesn't deceive us; it is we who deceive ourselves.
Dynamosaurus Imperiosus/ Raptorexxx 700
MemberCompsognathusJul-15-2014 9:54 AMCarnosaur....I agree with everything you said in the series as a whole up until now would you mind to do Utahraptor next as I would love to know its actual size to put on my site
Carnosaur
MemberCompsognathusJul-15-2014 10:01 AMsure! i'll work on it tonight :)
Nature doesn't deceive us; it is we who deceive ourselves.
Lord Vader
MemberTyrannosaurus RexJul-15-2014 10:55 AMNice post, looking forward to them all.
Jack of all trades. Master of none
Jezza
MemberCompsognathusJul-15-2014 1:32 PMI'll just ignore the evolution part.
The neural spines on his neck have a locking system which would require a good deal of muscle. I deffinately agree with it eating dinos other than sauropods. The spine was probably colored to atract mates, but as for just a skin covering, that's just something I don't think is the case. Your view points deffinately aren't stupid, most everyone have different sizes for dinosaurs, that's not a problem. There are so many different weighing methods and hypothesises, no one knows exactly which one's right. With dinos, you have to have some imagination, but not to the point where it completely defies what we know.
Youre fat, and I'm not sugarcoating it cause you'd probably eat that too.
Carnosaur
MemberCompsognathusJul-15-2014 1:39 PMThis has been discussed in the first description on page 714 to 715. You can read it here:
Acrocanthosaurus neural spines
The greatest problem in this question is probably that we assume morphological similarity to its relatives which lack such structures on their backs. The muscle attachment is possible, but there is no explanation why Acrocanthosaurus would have needed it more than its relatives. If it lived in drier climate than its relatives, fat storage would be plausible.
There are so many different weighing methods and hypothesises, no one knows exactly which one's right
Well, through tried and true methods we have an educated guess to how big these things got. I use several methods in my posts during this series, really leaving no stone unturned to get a best estimate. Unfortunately, that's all we can do because these things are extinct.
Nature doesn't deceive us; it is we who deceive ourselves.
Hiphopananomus
MemberCompsognathusJul-15-2014 2:03 PMGood post, think 5 tons and 11 metres is very possible.
"Somewhere on this island is the greatest predator that ever lived. Second greatest predator must take him down."Roland Tembo"
"Jurassic park: The Lost World"
