Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Tyrannosaurids: The Weightlifting Ballerinas of The Cretaceous
#1
"Carnotaurs were drag racers, Tyrannosaurids were rally monsters."
-SudsyMedusa53 on youtube


It should be noted that this study has not been peer reviewed yet, and some information may be subject to change. Lots of big names, though.

Essentially, this recently published study compares the agility values of Tyrannosaurids when compared to Allosaurids and a handful of other theropods. 

Click me for the full paper!

"With respect to other theropods, tyrannosaurids are increasingly agile without compromising their large body mass, such that in a pairwise comparison, tyrannosaurids are achieving the same agility performance of much smaller theropods (Figs. 3-5). For example, a 500 kg Gorgosaurus has slightly greater agility scores than the 200 kg Eustreptospondylus, and an adult Tarbosaurus nearly twice the agility scores of the lighter Sinraptor This agility performance stratification suggests that these two groups may have had different ecologies, inclusive of both feeding and locomotory strategies. Further, by including juveniles in our analysis through the use of independent inclusion vectors, we were further able to estimate performance capacity in younger life history stages. This revealed that agility performance is established relatively early in life and carries through to large adult body masses."

I'm not certain how this would carry over to the far more robust adult T. rex, but there are some new comparisons and even an updated aerial view of Tyrannosaurus rex itself.

[Image: s9lHk1e.png]

[Image: pa1FbBY.png]
[Image: ltiZ2aC.jpg]
[-] The following 3 users Like Maxilla's post:
  • Jinfengopteryx, Jurassicdangerousdinosaur, Suetherex
Reply
#2
Looks like the tyranosaurid family might be more agile than scientist make them out to be.
Reply
#3
It makes sense though. As they've argued in the discussion section, you need to be more agile against ceratopsians and hadrosaurs than against sauropods.

For those who need a very dumbed down explanation of what the agility numbers mean, they are basically the force in the legs divided by the force needed to accelerate.
[-] The following 1 user Likes Jinfengopteryx's post:
  • Maxilla
Reply
#4
really really intersting paper. I'm saving this and i will enjoy the read tomorrow.
[Image: t-rex-skull.jpg]
Reply
#5
Its a shame most people will still say that Tyrannosaurus could not run because of the media using out of date information.
[-] The following 1 user Likes Jurassicdangerousdinosaur's post:
  • Maxilla
Reply
#6
(01-05-2019, 07:27 AM)Jurassicdangerousdinosaur Wrote: Its a shame most people will still say that Tyrannosaurus could not run because of the media using out of date information.

Well, it's still up for debate as to how fast the animal could run for sure. My big takeaway from this paper was how fast the family could turn compared to its contemporaries.
[Image: ltiZ2aC.jpg]
Reply
#7
I haven't read about Dinos world and paleontology in a while so I'm using old resources here, but I clearly remember since my childhood conflicting information about Tyrannosaurus speed: an older Encyclopedia stated 50 km\h, and a newer one 25km\h.
There are still opinions so mixed about this topic?
Reply
#8
(01-06-2019, 02:44 AM)Carnivorous Vulgaris Wrote: I haven't read about Dinos world and paleontology in a while so I'm using old resources here, but I clearly remember since my childhood conflicting information about Tyrannosaurus speed: an older Encyclopedia stated 50 km\h, and a newer one 25km\h.
There are still opinions so mixed about this topic?

I’ll try to go more in detail later today, but yeah, those estimates are products of a long debate of how fast the creature was. However, I think we can rule out both of those particular extremes (25 km/h too low, 50 km/h too high).
[Image: 9wf8nho.png]
[-] The following 1 user Likes Ausar's post:
  • Carnivorous Vulgaris
Reply
#9
(01-06-2019, 02:02 AM)Maxilla Wrote:
(01-05-2019, 07:27 AM)Jurassicdangerousdinosaur Wrote: Its a shame most people will still say that Tyrannosaurus could not run because of the media using out of date information.

Well, it's still up for debate as to how fast the animal could run for sure. My big takeaway from this paper was how fast the family could turn compared to its contemporaries.

That is true but i think it is safe to say Tyrannosaurus could actually run there are plenty of people out there that say it flat out could not run at all then say they heard it on the news or read it on google. Its just like the old Tyrannosaurus is a pure scavenger debate sometimes i feel its finally going away and we have plenty of evidence to show it was not a pure scavenger and surely people know this then i turn on the telly and someone is still repeating the old theory or i look on the internet and there are still people repeating it ughhh it gets so frustrating.
Reply
#10
(01-06-2019, 04:38 AM)Jurassicdangerousdinosaur Wrote: That is true but i think it is safe to say Tyrannosaurus could actually run there are plenty of people out there that say it flat out could not run at all then say they heard it on the news or read it on google. Its just like the old Tyrannosaurus is a pure scavenger debate sometimes i feel its finally going away and we have plenty of evidence to show it was not a pure scavenger and surely people know this then i turn on the telly and someone is still repeating the old theory or i look on the internet and there are still people repeating it ughhh it gets so frustrating.

You know, Dinosaurs debating is fascinating to anyone cause it's all about suppositions and assumptions that (to a certain degree) nobody knows for sure. And since people love to debate, to be sectarian, and to have their own logic theories (or following existing ones they like more) Dinosaurs topics are fertile grounds for opinions of the widest range. Add to that ignorance and internet misinformation.
Reply
#11
(01-06-2019, 05:02 AM)Carnivorous Vulgaris Wrote:
(01-06-2019, 04:38 AM)Jurassicdangerousdinosaur Wrote: That is true but i think it is safe to say Tyrannosaurus could actually run there are plenty of people out there that say it flat out could not run at all then say they heard it on the news or read it on google. Its just like the old Tyrannosaurus is a pure scavenger debate sometimes i feel its finally going away and we have plenty of evidence to show it was not a pure scavenger and surely people know this then i turn on the telly and someone is still repeating the old theory or i look on the internet and there are still people repeating it ughhh it gets so frustrating.

You know, Dinosaurs debating is fascinating to anyone cause it's all about suppositions and assumptions that (to a certain degree) nobody knows for sure. And since people love to debate, to be sectarian, and to have their own logic theories (or following existing ones they like more) Dinosaurs topics are fertile grounds for opinions of the widest range. Add to that ignorance and internet misinformation.


Yeah you are right i should really just not let it get to me as much as i let it sometimes. At least it is not to bad on here in fact it is pretty great when compared to platforms such as youtube there is so much misinformation being thrown around on there when it comes to certain dinosaurs i have a stroke every time i look at the comment section.
Reply
#12
(01-06-2019, 02:59 AM)Ausar Wrote:
(01-06-2019, 02:44 AM)Carnivorous Vulgaris Wrote: I haven't read about Dinos world and paleontology in a while so I'm using old resources here, but I clearly remember since my childhood conflicting information about Tyrannosaurus speed: an older Encyclopedia stated 50 km\h, and a newer one 25km\h. 
There are still opinions so mixed about this topic?

I’ll try to go more in detail later today, but yeah, those estimates are products of a long debate of how fast the creature was. However, I think we can rule out both of those particular extremes (25 km/h too low, 50 km/h too high).

First, it should be noted the topic of this thread concerns agility, not speed, so this post is kind of off topic. Nevertheless:

Why I don't think Tyrannosaurus rex could run at 30 mph

Tyrannosaurus was an animal that weighed about 6 to 7 tonnes. It could weigh even more than that, actually. Hirt et al. (2017) found that, as could probably have been expected before, that the fastest animals are neither the smallest nor the fastest, and their graph (Fig. 4) for speed (km/h) versus body mass (kg) in animals (with both extant species and extinct dinosaurs) shows an increase in speed with body mass, but then a decline in speed by a certain threshold. When I emailed Greg Paul (yes, the Greg Paul) a while back on what he thought of this paper (and Sellers et al. 2017), he replied with a press release he made about them. What he showed was the same figure I mentioned above, and it appears that according to Hirt et al.'s data, the actual potential top speed for an animal weighing 6-7 tonnes is actually 30 mph (although, they estimated T. rex to have a maximum speed well below this). Here is an attachment of the data Paul sent me with the 6-7 tonne mark labeled.

[Image: 2zxw3tz.jpg]


So, 30 mph shouldn't be totally out of the question for terrestrial animals this big, right?

Well, here's the thing. I looked into their supplementary information for details about their data, and when I looked at their data for animal speed, I paid particular attention to the only terrestrial animal alive today that rivals Tyrannosaurus rex in body mass: the African bush elephant. They had three different maximum speed figures corresponding to three body masses (two at 6,000 kg, one at 8,000 kg). And what did they say for that? They said 34.02-35 km/h for a 6 tonne elephant and 40 km/h for an 8 tonne elephant...

Yeah...no.

Also, one of their speed estimates for the 4,000 kg Asian elephant is no better, at 34 km/h (while the other, also for a 4t Asian elephant, was at 7 km/h, which is certainly too low). 

Elephants do not reach speeds of 40, or even 30 km/h. The maximum reliably recorded speed estimates for elephants was 24.48 km/h, or 15.2 mph (Hutchinson et al. 2003, 2006)*. Why is all this relevant? I think Hirt et al.'s incorrect data input of elephants reaching the aforementioned speeds of >30 up to 40 km/h inflated the maximum possible speed a 6-7 tonne animal could run at up to 30 mph. Otherwise, I see nothing wrong with Hirt et al.'s data (although, I'm not an über expert on exactly how fast every single species can run at), so taking their error with 6+ tonne animals into account, I do not think 30 mph is possible at this size range or above.

*It should be noted that the particular elephant specimen that reached this speed was a bull that weighed <3 tonnes (Hutchinson et al. 2003), so it was clearly not an adult (male Asian elephants weigh 4 tonnes as adults). This could mean adult elephants are even slower than that, but I'm not even going to get into that, lest I make this whole thought process too complicated.

Why I don't think Tyrannosaurus rex was limited to speeds of 25 km/h

However, I similarly think 25 km/h is too low of a maximum speed for the tyrant lizard king. As I just stated above, elephants are limited to maximum ambling speeds of 24.48 km/h. 25 km/h is negligibly faster than that. What's wrong with elephants being comparable in speed to Tyrannosaurus you might ask? I'll just leave you with the data dump below.

With particular regards to bone strength: there is a 2017 paper which states that Tyrannosaurus didn't have enough bone strength for running, but that's another thing I don't feel like getting into right now. I will say, though, that there are some aspects of that paper that appear wanting, but its speed estimate of 7.7 m/s for T. rex isn't all that unreasonable anyway.

Quote:Columnar, unflexed legs with inflexible ankles and short feet prevent elephants from reaching a full run, thus limiting them to a top speed of about 25 km/h (Paul 2000; Hutchinson et al. 2003). Elephants are not slow because they are gigantic-even juvenile elephants are no faster than the adults-but because they are anatomically adapted to be slow, a result of having descended from semiaquatic herbivores and living in a world free of gigantic predators. A major portion of the mass of mammalian megaherbivores (sensu Owen-Smith 1988) is concentrated in the plant-fermenting gut. About 10 to 20% of a large, healthy herbivore's mass consists of forage and feces (Robertson-Bullock 1962; Short 1963). Because rhino legs are so short, the small locomotor muscle mass is apparently a large portion of total mass. The limited available data suggest [sic] that elephants do not have large leg muscles (Robertson-Bullock 1962), and their limb anatomy is not able to effectively convert their power into speed.

Adult tyrannosaurids descended from and grew up from fast runners, and they were probably empty-bellied, flexed-limbed predators with mobile ankles that emphasized nonlocomotor weight reduction in favor of expanded leg muscles.
The 1- to 3-tonne Albertosaurus and Daspletosaurus had much longer, more distally gracile, birdlike legs than similar-sized rhinos, and they were the most speed adapted tetrapods in their size class. It is improbable that they were slower, and may have been actually faster, than rhinos. T. bataar and T. rex were only two or three times heavier than Albertosaurus and Daspletosaurus, and they possessed the same ratitelike running adaptations. Hence, the speed potential of giant tyrannosaurids was not lower than [that of] their lesser relatives on a morphological basis, and they were uniquely speed adapted for their size class. The anatomy of T. rex was adapted to exploit the maximum practical power production of its enormous leg muscles, weighing between 1.2 and 2.4 tonnes, to produce speed. There is simply no comparison between the locomotor apparatus of the similar-sized giants.

Quote:There is a correlation between muscle attachment area and speed among birds and mammals. Fast running cheetah, canids, gazelles and horses have more mass than slower cattle and goats (Taylor et al., 1974; Hoppler et al., 1987). In slow elephants and humans the ilium is not long, and anchors a narrow thigh musculature. Faster running mammals and birds have longer ilia that anchor a broader, more powerful thigh musculature. Birds have large cnemial crests and hypotarsi that anchor a powerful "drumstick" shank musculature.

Quote:They [elephants] are the classic example of a graviportal animal, possessing massive pillar-like legs for supporting their weight (Gray, 1968). They walk or amble rather than run.

Quote:Because big-hipped, bird-like Tyrannosaurus was much better adapted for running than are elephants, it is unlikely that it was similarly slow, and other estimates suggest that giant theropods could run almost twice as fast as elephants, matching rhinos and nonthoroughbred horses.

Quote:Big gallopers today possess strong knee muscles that attach to the kneecap and shank in such a way that the knee joint opens and closes under tremendous muscular power. A bony ridge, the cnemial (silent c here: "nee-mee-al") crest, marks the point of attachment for the knee tendons, and one can directly gauge the muscle power of a knee from the size of a cnemial crest. Elephants, turtles, and salamanders are all slowpokes in their body-size classes and all have puny knee muscles and low cnemial crests on the shank bone. Rhinos have big cnemial crests, as do other large-bodied gallopers, such as water buffalo, giraffe, bison, and gaur. Big crests would also mean big calf muscles. All dinosaurs had bigger cnemial crests than do elephants, even those groups with relatively straight hind legs—the giant horned dinosaurs, stegosaurs, and brontosaurs. When these systems of oversized knee muscles contracted, the power exerted on the hind paw would have had no equal today. The biggest meat-eater, three ton-plus Tyrannosaurus, had an absolutely huge cnemial crest, even by dinosaurian standards.

Quote:A quite different approach to the question of dinosaur speed is provided by calculating the maximum strength of the bone shafts of the limbs. Legs do break in nature, and evolution usually outfits a species with bone shafts strong enough to withstand the highest strains imposed when muscles contract. Rhinos have relatively stout, thick-shafted legs. Elephants feature a more spindly design. To measure the shaft strength of dinosaur limbs, I constructed scale models in clay of the life appearance of various species. I then calculated the live weight by measuring the volume of the model (most land animals are a little less dense than water, so live weight is about 95 percent of the body's volume in water). Brontosaurs and stegosaurs were somewhat thin-thighed, and in cross section their bones are about as thick as we would expect in an elephant of similar size. But Triceratops, Tyrannosaurus, and the other predators were much more massively shafted, far stronger in girth of bone, and these dinosaurs could exert positively prodigious force through their limbs without fear of fracture.

Quote:Alexander (1989) estimated that the type Tyrannosaurus femur was too weak for a fast gait. Estimated body mass was 8000 kg, but this was based on an inaccurate toy model. A technical restoration of the type specimen cannot distinguish its mass from the similar sized and more complete AMNH 5207, which is estimated via a careful skeletal restoration and model to mass 5700 kg (Paul 1988, 1987). The type femur is preserved intact, and is therefore more robust than that of MOR 555 (Fig. 6). At 5700 kg, femur strength is similar to that of an ornithomimid (Farlow, 1990). This suggests that giant tyrannosaur limb bones were as well able to withstand running forces as those of their smaller relatives.

As the first excerpt says, tyrannosaurids are already more adapted for fast running courtesy of the characteristics mentioned above. This however, ignores all the other cursorial adaptations tyrannosaurids like Tyrannosaurus had.

Quote:In examining absolute limb lengths in theropods, it is found that both the tibia and metatarsus increase as femur length increases. These elements both grow with negative allometry (allometric slopes of 0.91 and 0.93 when the log of tibia length or log metatarsal III length are plotted against log femur length, respectively), so that as femur size increases, the relative size of the tibia and metatarsus decreases. This phenomenon is common to many groups of animals, including ungulate, carniverous [sic], and marsupial mammals, and many groups of flightless birds (Holtz, 1995). For a given femur length, however, tyrannosaurids and ornithomimids have a longer absolute (and thus relative) tibia and metatarsus length than those of other theropods.

In other words, for a given femur length, tyrannosaurids have a longer distal limb length than those of most other theropods. Similarly, tyrannosaurids and ornithomimids of the same femur length have comparable tibia and metatarsus lengths. Thus, for a given angle of motion of the femur, a tyrannosaur could cover more distance than an allosauroid, ceratosaur, or other large-bodied theropod of the same femur length. Because distance covered per unit of time is the definition of speed, all other things being equal, tyrannosaurids should have been faster than any other comparably-sized theropod.

Quote:The arctometatarsus is a modified metatarsal form that has been linked to fast linear locomotion and enhanced agility.

Quote:Energy was transferred from the wedge-like middle metatarsal to the outer elements of the foot, where it was absorbed by ligaments, functionally unifying the metapodials and thus reducing loads on the middle metatarsal during locomotion (Snively &amp; Russell 2002: p. 40). The Tyrannosauroid ilium is very long, often exceeding the femur length (Holtz 2004: p. 124) and the thigh muscles were massive (Hutchinson et al. 2011: p. 14).

Quote:The ilial plate that the thigh muscles anchored upon was similarly large-and larger than in most other theropods-in ornithomimids and tyrannosaurids of all sizes. The shank musculature also appears to have been powerful. Proximally, the cnemial crest was well developed over the entire size range. Distally, it has not been recognized that there was a true hypotarsus on metatarsal II in theropods; it was well developed in ornithomimids and tyrannosaurids regardless of size (Fig. 4E).

Quote:The astragular condyles were large rollers (probably enlarged by cartilage surfaces as in non-mature birds) that allowed the tarsometatarsus to rotate through an arc of about 150°, from nearly straight to nearly collapsed relative to the tibia-fibula (Fig. 4F). The foot was long in these theropods. Therefore the foot had the excursion arc and length needed to propel the body into a suspended phase in ornithomimids and tyrannosaurids small and gigantic.

Quote:Fact, Tyrannosaurs rex's ilia are tightly oppressed, almost to a point where the sacral neural spines are crushed, more than any other theropod; meaning large muscles. Giganotosaurus doesn't have this. The cnemial crest on the tibia is HUGE. If the animal didn't move fast why have such a huge cnemial crest?

Quote:Because ornithomimids were gracile limbed cursors, and because the limb form of increasingly gigantic tyrannosaurids were an allometric continuation of the former, adult tyrannosaurids were effectively as "gracile" limbed and potentially as cursorial as ornithomimids and juvenile tyrannosaurids, and about as gracile and as cursorial as such enormous animals could have been.

Quote:If T. rex was a "slow runner, at best" (Hutchinson and Garcia 2002, p. 1021), then tyrannosaurids of increasing size should have become increasingly and dramatically anatomically adapted for slow speeds (Paul 1988a). Instead, tyrannosaurids of all sizes were remarkably uniform in having been the most anatomically speed adapted land animals in their size classes. What changes there are are modest, and are limited largely to changing proportions in terms of increasing robustness and distal shortening of distal segments with increasing bulk. Lower limb gracility and segment ratios do not necessarily indicate slower speed outside the same size class. The tyrannosaurids' size-related changes in limb proportions are of the order observed in ungulates that maintain a constant absolute top speed as they mature. Therefore, the stouter construction of T. rex does not, a priori, indicate a loss of speed, any more than the heavier build and shorter distal limb elements of an adult zebra indicate that it is slower than the much more gracile foal, which is no faster than it [sic] parent. It is therefore not a given that giant tyrannosaurids lost speed as they matured or evolved greater size.

Let's also not forget the beefy, muscular tails of theropods like Tyrannosaurus that had a huge M. caudofemoralis that would have greatly increased maximum speed, something that elephants lack entirely.

Quote:Because the M. caudofemoralis is the primary hind limb retractor, large M. caudofemoralis masses and the resulting contractile force and torque estimates presented here indicate a sizable investment in locomotive muscle among theropods with a range of body sizes and give new evidence in favor of greater athleticism, in terms of overall cursoriality, balance, and turning agility.


And here are the references for the above excerpts.

- Larson, P.L., Carpenter, K. (2008). Tyrannosaurus rex, the Tyrant King (pp. 323-324 &amp; p. 378). Indiana University Press
- Langman, V.A., Roberts, T.J., Black, J., Maloiy, G.M.O., Heglund, N.C., Weber, J.-M., Kram, R., Taylor, C.R. (1995). Moving cheaply: energetics of walking in the African elephant. The Journal of Experimental Biology 198, 629-632.
- Paul, G.S. (1998). Limb design, function and running performance in ostrich-mimics and tyrannosaurs. Gaia, 257-270.
- IV Persons, S.W., Currie, P.J. (2016). An approach to scoring cursorial limb proportions in carnivorous dinosaurs and an attempt to account for allometry. National Center for Biotechnology Information. doi: 10.1038/srep19828.
- Nau, D. (2015). Comparative, functional anatomy of prey acquisition and feeding adaptations in non-avian theropods. (pp. 21-22).
- IV Persons, S.W., Currie, P.J. (2010). The Tail of Tyrannosaurus: Reassessing the Size and Locomotive Importance of the M. caudofemoralis in Non-Avian Theropods. The Anatomical Record, 119-131. doi: 10.1002/ar.21290
- Paul, G.S. (2010). The Princeton Field Guide to Dinosaurs (p. 31). Princeton University Press.
- Bakker, R.T. ( 1986). The Dinosaur Heresies: New Theories Unlocking the Mystery of the Dinosaurs and Their Extinction, pp. 217-218.
- http://dml.cmnh.org/2002Mar/msg00007.html
[Image: 9wf8nho.png]
[-] The following 3 users Like Ausar's post:
  • Carnivorous Vulgaris, Jinfengopteryx, Verdugo
Reply
#13
Wow, thanks Ausar, my paleontology lord; this is a really beautiful analysis, it reignited my interest in this beast. The Elephant comparisons and the conclusion seem very reasonable, and in my ignorance I cannot not agree.

I remember around the early2000s there was this theory of T-rex being way slower than we thought, and a representation(a documentary) of the Tyrannosaurus max speed that basically showed it walking like a man; I mean, they showed the Dino obese, dragging, with its tail almost touching the ground. I thought it was so stupid, so it stuck with me. Reading your post, about the bones and the tail advantage over the Elephant, made me remember that. It's incredible how theories may vary; sometimes people are so eager to make their mark, that they have no time to be logical.

PS: It may even be a bit off topic, but reading all you wrote I think it makes sense in this thread (agility, body structure, bones..).
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)