How big were the biggest sauropod trackmakers?

October 13, 2009

UPDATE December 3, 2009

I screwed up, seriously. Tony Thulborn writes in a comment below to correct several gross errors I made in the original post. He’s right on every count. I have no defense, and I am terribly sorry, both to Tony and to everyone who ever has or ever will read this post.

He is correct that the paper in question (Thulborn et al 1994) does discuss track length, not diameter, so my ranting about that below is not just immoderate, it’s completely undeserved. I don’t know what I was thinking. I did reread the paper before I wrote the post, but I got the two switched in my mind, and I assigned blame where none existed. In particular, it was grossly unfair of me to tar Tony’s careful work with the same brush I used to lament the confused hodgepodge of measurements reported in the media (not by scientists) for the Plagne tracks.

I am also sorry that I criticized the 1994 paper and implied that the work was incomplete. I was way out of line.

I regard this post as the most serious mistake in my professional career. I want very badly to somehow unmake it. I am adding corrections to the post below and striking out but not erasing my mistakes; they will stand as a reminder of my fallibility and a warning against being so high-handed and unfair in the future.

I’m sorry. I beg forgiveness from Tony, from all of our readers, and from the broader vertebrate paleontology community. Please forgive me.

–Mathew Wedel

Plagne sauropod track

You might have seen a story last week about some huge sauropod tracks discovered in Upper Jurassic deposits from the Jura plateau in France, near the town of Plagne. According to the news reports, the tracks are the largest ever discovered. Well, let’s see.

The Guardian (from which I stole the image above) says the prints are “up to 2 metres (6ft 6 in) in diameter”, but ScienceDaily says “up to 1.5 m in total diameter”. Not sure how ‘total diameter’ is different from regular diameter, but that’s science reporting for you. The BBC clarifies that, “the depressions are about 1.5m (4.9ft) wide”, which might be the key here (see below), but then mysteriously continues, “corresponding to animals that were more than 25m long and weighed about 30 tonnes.” I find it rather unlikely that a pes track 1.5 m wide indicates an animal only as big as Giraffatitan (hence this post).

So there’s some uncertainty with respect to the diameter of the tracks–half a meter of uncertainty, to be precise. But sauropod pes tracks are usually longer than wide, and a print 1.5 m wide might actually be 2 m long.

Not incidentally, Thulborn (1994) described some big sauropod tracks from the Broome Sandstone in Australia, with pes prints up to 1.5 m. Although the photos of the tracks are not as clear as one might wish, they do appear to show digit impressions and are probably not underprints. [See Tony Thulborn’s comment below regarding footprints vs underprints.]

I’ll feel a lot better about the Plagne tracks when the confusion about their dimensions is cleared up and when some evidence is presented that they also are not underprints. In any case, the only dimension with any orientation cited for the Plagne tracks is the 1.5 m width reported by the BBC, so we’ll go with that. So the Plagne tracks might only tie, but not beat, Thulborn’s tracks.

Then again, Thulborn only said that the biggest tracks were up to 150 cm in diameter. What does that mean–length? Width? Are the tracks perfect circles? Does no one who works on giant sauropod tracks know how to report measurements? These questions will have to wait, because despite the passing of a decade and a half, the world’s (possibly second-) biggest footprints–from anything! ever!–have not yet merited a follow-up paper. [Absolutely wrong and unfair; please see the apology at top and Tony Thulborn’s comment below.]

Nevertheless, for the remainder of this post we’ll accept that at least some sauropods were leaving pes prints a meter and a half wide. Naturally, it occurs to me to wonder how big those sauropods were. I don’t know of any studies that attempt to rigorously estimate the size of a sauropod from its tracks or vice versa, so in the finest tradition of the internet in general and blogging in particular, I’m going to wing it.

How Big?

First we need some actual measurements of sauropod feet. When Mike and I were in Berlin last fall (gosh, almost a year ago!), we measured the feet (pedes) of the mounted Giraffatitan and Diplodocus for this very purpose. The Diplodocus feet were both 59 cm wide, and the Giraffatitan feet were 68 and 73 cm wide. The Diplodocus feet are trustworthy, the Giraffatitan bits less so. Unfortunately, the pes is the second part of the skeleton of Giraffatitan that is less well known than I would like (after the cervico-dorsal neural spines). The reconstructed feet look believable, but “believability” is hard to calibrate and probably a poor predictor of reality when working with sauropods.

One thing I won’t go into is that Giraffatitan (HM SII) probably massed more than twice what Diplodocus (CM 84/94) did, but on the other hand G. bore more of its weight on its forelimbs. It would be interesting to calculate whether the shifted center of mass would be enough to even out the pressure exerted by the hindfeet of the two animals; Don Henderson may have done this already.

Anyway, let’s say for the sake of argument that the hindfeet of the mounted Giraffatitan are sized about right. The next problem is figuring out how much soft tissue surrounded the bones. In other words, how much wider was the fleshy foot–deformed under load!–than the articulated pes skeleton? I am of two minds on this. On one hand, sauropods probaby had a big heel pad like that of elephants, and it seems reasonable that the heel pad plus the normal skin, fat, and muscle might have expanded the fleshy foot considerably beyond the edges of the bones. On the other hand, the pedal skeleton is widest across the distal ends of the phalanges, and in well-preserved tracks like the one below the fleshy foot is clearly not much wider than that (thanks, Brian, for the photo!).


Bear in mind that a liberal estimate of soft tissue will give a conservative estimate of the animal’s size, and vice versa. Looking at the AMNH track pictured above, it seems that the width added by soft tissue could possibly be as little as 5% of the width of the pes skeleton. Skewing hard in the opposite direction, an additional 20% or more does not seem unreasonable for other animals (keep in mind this would only be 10% on either side of the foot). Using those numbers, Diplodocus (CM 84/94) would have left tracks as narrow as 62 cm or as wide as 71 cm. For Giraffatitan (HM SII) I’ll use the wider of the two pes measurements, because the foot is expected to deform under load and the 73 cm wide foot looked just as believable as the 68 cm foot (for whatever that’s worth). Applying the same scale factors (1.05 and 1.20) yields a pes track width of 77-88 cm.

These numbers are like pieces of legislation, or sausages: the results are more pleasant to contemplate than the process that produced them. They’re ugly, and possibly wrong. But they give us someplace to start from in considering the possible sizes of the biggest sauropod trackmakers. Something with a hindfoot track 1.5 meters wide would be, using these numbers, conservatively more than twice as big as (2.11x) the mounted Carnegie Diplodocus or 170% the size of the mounted Berlin Giraffatitan. That’s right into Amphicoelias fragillimus/Bruhathkayosaurus territory. The diplo-Diplodocus would have been 150 feet long, and even assuming a very conservative 10 tons for Vanilla Dippy (14,000L x 0.7 kg/L = 9800 kg), would have had a mass of 94 metric tons (104 short tons). The monster Giraffatitan-like critter would have been “only” 130 feet long, but with a 14.5 meter neck and a mass of 113 metric tons (125 short tons; starting from a conservative 23 metric tons for HM SII).

Keep in mind that these are conservative estimates, for both the size of the trackmakers and the masses of the “known” critters. If we use the conservative soft tissue/liberal animal size numbers, the makers of the 1.5 meter tracks were 2.4 times as big as the mounted Diplodocus or almost twice as big as the mounted Giraffatitan, in which case masses in the blue whale range of 150-200 tons become not just probable but inevitable.

Mike measuring Giraffatitan's naughty bits. Check out the hindfeet. Also note the sauropod vertebrae in the background--titular obligation fulfilled!

Mike measuring Giraffatitan's naughty bits. Check out the hindfeet. Also note the sauropod vertebrae in the background--titular obligation fulfilled!

Too Big?

Going the other way, I can think of only a handful of ways that the “conservative” trackmaker estimates might still be too big:

First, the pes of Giraffatitan might have been bigger than reconstructed in the mounted skeleton. Looking at the photo above, I can image a pes 10% wider that wouldn’t do any violence to the “believability” of the mount. That would make the estimated track of HM SII 10% wider and the estimated size of the HM-SII-on-steroids correspondingly smaller. But that wouldn’t affect the scaled up Diplodocus estimate, and the feet of Giraffatitan would have to be a LOT bigger than reconstructed to avoid the reality of an animal at least half again as big as HM SII.

Second, the amount of soft tissue might have been greater than even the liberal soft tissue/conservative size estimate allows. But I think that piling on 20% more soft tissue than bone is already beyond what most well-preserved tracks would justify, so I’m not worried on that score. (What scares me more is the thought that the conservative estimates are too conservative, and the real trackmakers even bigger.)

Third, I suppose it is possible that sauropod feet scaled allometrically with size and that big sauropods left disproportionately big tracks. I’m also not worried about this. For one thing, when they’ve been measured sauropod appendicular elements tend to scale isometrically, and it would be weird if feet were the undiscovered exception. For another, the allometric oversizing of the feet would have to be pronounced to make much of a dent in the estimated size of the trackmakers. I find the idea of 100-ton sauropods more palatable than the idea of 70-ton sauropods with clown shoes.

Fourth, the meta-point, what if the Broome and Plagne tracks are underprints? [Please see Tony Thulborn’s comment below regarding footprints and underprints.] I’ve seen some tracks-with-undertracks where the magnification of the apparent track size in the undertracks was just staggering. The Broom tracks have gotten one brief note and The Plagne tracks have not been formally described at all, so all of this noodling around about trackmaker size could go right out the window. Mind you, I don’t have any evidence that the either set are underprints, and at least for the Broome tracks the evidence seems to go the other way, I’m just trying to cover all possible bases.


So. Sauropods got big. As usual, we can’t tell exactly how big. Any one individual can leave many tracks but only one skeleton, so we might expect the track record to sample the gigapods more effectively than the skeletal record. Interestingly, the largest fragmentary skeletal remains (i.e., Amphicoelias and Bruhathkayosaurus, assuming they’re legit) and the largest tracks (i.e., Plagne and Broome) point to animals of roughly the same size.

It’s also weird that some of the biggest contenders in both categories have been so little published. I mean, if I had access to Bruhathkayosaurus or a track 1.5 m wide, you can bet that I’d be dropping everything else like a bad habit until I had the gigapod evidence properly written up. What gives? [The implication that the Broome tracks were not properly written up is both wrong and unfair; please see the apology at top.]

Finally, IF the biggest fragmentary gigapods and the biggest tracks are faithful indicators of body size, they suggest that gigapods were broadly distributed in space and time (and probably phylogeny). I wonder if these were representatives of giga-taxa, or just extremely large individuals of otherwise vanilla sauropods. Your thoughts are welcome.

Epilogue: What About Breviparopus?

It’s past time someone set the record straight about damn Breviparopus. The oft-quoted track length of 115 cm is (A) much smaller than either the Broome or Plagne tracks, and (B) the combined length of the manus and pes prints together; I know, I looked it up (Dutuit and Ouazzou 1980). Why anyone would report track “length” that way is beyond me, but what is more mysterious is why anyone was taken in by it, since the width of 50 cm (pathetic!) is usually quoted along with the 115 cm “length”, indicating an animal smaller than Vanilla Diplodocus (track length is much more likely than width to get distorted by foot motions during locomotion) [This part is wrong; see the update below.]. But people keep stumbling on crap (thanks, Guiness book!) about how at 157 feet long (determined how, exactly?) Breviparopus was possibly the largest critter to walk the planet. Puh-leeze. If there’s one fact that everyone ought to know about Breviparopus, it’s that it was smaller than the big mounted sauropods at museums worldwide. The only thing super-sized about it is the cloud of ignorance, confusion, and hype that clings to the name like cheap perfume. Here’s the Wikipedia article if you want to do some much-needed revising.

UPDATE (Nov 17 2009): The width of the Breviparopus pes tracks is 90 cm, not 50 cm. The story of the 50 cm number is typically convoluted. Many thanks to Nima Sassani for doing the detective work. Rather than steal his thunder, I’ll point you to his explanation here. Point A above is still valid: Breviparopus was dinky compared to the Broome and Plagne trackmakers.

Parting Shot

You know I ain’t gonna raise the specter of a beast 1.7 times the size of HM SII without throwing in a photoshopped giant cervical. So here you go: me with C8 of Giraffatitan blown up to 170% (the vert, not me). Compare to unmodified original here.



  • Dutuit, J.M., and A. Ouazzou. 1980. Découverte d’une piste de Dinosaure sauropode sur le site d’empreintes de Demnat (Haut-Atlas marocain). Mémoires de la Société Géologique de France, Nouvelle Série 139:95-102.
  • Thulborn, R.A., T.Hamley and P.Foulkes. 1994. Preliminary report on sauropod dinosaur tracks in the Broome Sandstone (Lower Cretaceous) of Western Australia. Gaia 10:85-96.

35 Responses to “How big were the biggest sauropod trackmakers?”

  1. Jamie Stearns Says:

    Interestingly, that blown up cervical, when compared to Matt Wedel, is similar in size to the “Aegyptosaurus sp.” vertebra that Stromer was depicted with in an earlier post on this blog. I suspect the latter might actually have been a Paralititan vert.

  2. Nima Says:

    That expose` on Breviparopus is truly shocking… In Greg Paul’s 1988 paper on Giraffatitan, he gave measurements for HMN SII’s heel pad as 750 mm (or 75 cm, which fits pretty well with your 73 cm measurement of the actual foot bones…)

    BUT for Breviparopus he gave the width as 900 mm or 90 cm, which is a good deal LARGER than HMN SII, and a LOT larger than a 50 cm Diplodocus foot (which ironically is Paul’s measurement for the foot pad of D. carnegiei CM 84).

    just for comparison, the largest “Paluxy river brachiosaur” prints are 87 cm wide… so if Paul is right about Breviparopus, it truly was a giant.

    I’m not sure where he got the 900 mm measurement though… though he does list it as a BREADTH measurement, not a length one… and he does cite Dale Russell (1980) in support of this fact. So it’s not only Dutuit and Ouzzau…

    I’d love to get my hands on any of these prints and at least take a few photos with a ruler for some measure of scale!

  3. William Miller Says:

    I assume Bruhathkayo’s bones are languishing in a jealously guarded museum drawer somewhere; but wouldn’t the Broome tracks still be sitting around outside in public view? How come no one else has done anything with them — are no Australian paleontologists interested in gigapods???

  4. Nathan Myers Says:

    Slightly off-topic:

  5. Gunnar Says:

    Aren’t footprints known to expand? Has there been made general models of footprint / weight ratios for extant animals?

  6. Rexisto Says:


    Not mastered the English language, as I speak Spanish but I was very interested in your article and I think I can help solve the mystery of giant footprints.

    The footprints supposedly measured 1.5 meters long, is very rare to mention the wide although it is very useful as you mention. As is the case with several tracks like Gigantosauropus asturiensis, sauropods strokes are often surrounded by petrified mud to less experienced eyes might seem genuine part of the footprint and thereby increase the estimate thereof.

    The two meters would then be the mark of mud. Yet traces of 1.5 meters are rounded and may be higher or lower by a few centimeters.

    For the photos I suppose they are more similar to Parabrontopodus (thus belonging to a Diplodocoidea) than Breviparopus (Apatosaurinae) or of Brontopodus (Macronaria baseline).

    Thulborn announces footprints of 1.55 meters and informally announced that the largest would be 1.7 meters. These are very different from those discovered in France and come closest to Brontopodus.

    In the blog I published dinosaur scales using the magnificent silhouette of Gregory Paul, Scott Hartmann, among others. The result is they see on Palaeoanatomía section and paragraph Paleofisiología Dinosauria.

    For more information is the subject Megasauropoda 3. Although the estimate of the tracks that are mentioned in an update at the bottom of the topic. Taking into account the length of the animal would have a footprint of 2.98 meters femur.

    A great guy only surpassed by Parabrontopodus distercii, Amphicoelias fragillimus, Bruhatkhayosaurus matleyi and “Brontopodus of Broome, Australia” in length of the femur. Because “Brachiosaurus” nougaredi, the traces of Bolivia and Puertasaurus titanosaurus Reuili be heavier.


  7. David Marjanović Says:

    What about the possibility that the Plagne footprints could have been made in very soft mud? (A lot of mud, it goes without saying, is “very soft” when we’re talking about an animal of such weight.) Apart from messing with the size, that would also explain why there’s so little detail, wouldn’t it?

    I love the terms “diplo-Diplodocus” and “gigapod”.

    Very interesting information about Breviparopus. The “48 m” figure is almost all I knew about it.

    I assume Bruhathkayo’s bones are languishing in a jealously guarded museum drawer somewhere

    Absolutely not in a drawer.

  8. William Miller Says:

    Ah, true… they probably couldn’t find a drawer big enough.

    More seriously, why *hasn’t* anyone published on it in years?

  9. William Miller Says:

    Probably the worst I’ve ever seen was on an ‘educational’ website saying Diplodocus footprints were 270 centimeters long.

  10. Mike Taylor Says:

    More seriously, why *hasn’t* anyone published on [Bruhathkayosaurus] in years?

    It’s one of the great mysteries of palaeo that no-one seems to care scientifically about super-giant sauropods. Don’t forget that the Sauroposeidon holotype was given to an UNDERGRAD to describe; in light of that, the continuing neglect of Bruhath is maybe not quite so bizarre.

    I guess the big skeleton in Bruhath’s closet is that no-one knows what it really is — the published “description” is a piece of crap, and assigned it to Theropoda. There’s been public speculation that the giant tibia is actually a tree-trunk. It might be a titanosaur, or … Well, who wants to blow thousands of pounds on travel to find that there is no sauropod at the other end? And even if there is, I have no idea what political issue there might be in publishing on it.

  11. David Marjanović Says:

    It’s one of the great mysteries of palaeo that no-one seems to care scientifically about super-giant sauropods.

    Perhaps out of an irrational – childish – fear that one might appear to be childish.

    After all, for several decades, being interested in dinosaurs at all was considered childish. All the great vertebrate paleontologists worked on mammal origins during that time.

  12. Michael O. Erickson Says:

    Please pardon my stupid ignoramus self, but why was Bruhathkayosaurus ever even removed from Theropoda? Was it just considered to be too honkin’ huge to be a theropod? From a scientific standpoint, “it’s too big” ain’t all that compelling.

  13. William Miller Says:

    >>Perhaps out of an irrational – childish – fear that >>one might appear to be childish.

    I think that’s a lot of it.

    Apropos quote: “When I became a man I put away childish things, including the fear of childishness and the desire to be very grown up.” – C. S. Lewis

    >>All the great vertebrate paleontologists worked on >>mammal origins during that time.

    Which has always been incomprehensible to me. Sure, they’re more closely related to humans, but honestly? Early mammals are boring. (Except Repenomamus, but they didn’t know about that one then.)

  14. Mike Taylor Says:

    Thanks, William — I’d made a mental note to look out that very C. S. Lewis quote in response to David’s observation. It’s cool that someone else did it first!

  15. Tony Thulborn Says:

    Wedel misrepresents the published work of others, including me, and then adds insult to injury by questioning the competence of those he has misrepresented.

    He seems unsatisfied, perhaps even irritated, by a preliminary report on Broome (Western Australia) sauropod tracks published in 1994 – which, incidentally, was the joint work of three authors, not just me. As both my co-authors (Tim Hamley and Paul Foulkes) are now dead and unable to defend themselves, I’ll have to respond for all three of us. Let me deal with Wedel’s remarks one by one, though not necessarily in the order in which he presents them.

    1) “Thulborn only said that the biggest tracks were up to 150 cm in diameter.”
    Nowhere does that 1994 paper state that the biggest tracks “were up to 150 cm in diameter”. I just checked it again (Gaia, vol. 10: 85-94), several times, and there is no such statement or anything resembling it. The word “diameter” appears only once, referring to a camera lens-cap (diameter 5.5 cm) used as an improvised indication of scale in one photograph (caption to Fig. 4D).
    Does that 1994 paper mention “only” that single dimension of 150 cm? Page 89 describes sauropod tracks in lagoonal settings: “The pes prints are usually subcircular, elliptical or oval in outline, with a length between 45 cm and 120 cm.” That’s length, not diameter.
    Page 92 deals with sauropod tracks in swamp/forest settings: “Most [have]… pes length between 45 cm and 90 cm, though there are a few larger tracks, with pes length greater than 1 m (e.g. Fig. 3D).” Again, that’s length, not diameter.
    And (also p. 92) “In addition … [there are] some seemingly novel types… For example, one very large form of pes print, with bean-shaped outline and clearly-defined notches representing the digits, attains a maximum length greater than 150 cm (Fig. 3D).” Once again that’s length, not diameter. And it’s the only point at which a figure of 150 cm is mentioned.

    2) “… up to 150 cm in diameter. What does that mean–length? Width? Are the tracks perfect circles?”
    No. It means that Wedel is inventing imaginary flaws in a paper that he doesn’t seem to have read.

    3) “Does no one who works on giant sauropod tracks know how to report measurements?”
    That statement reveals an undercurrent of baseless innuendo, usually in the form of rhetorical questions.
    As it happens, I do know how to report measurements of fossil footprints. So, too, did my co-authors Paul Foulkes and Tim Hamley. Giuseppe Leonardi, author of a standard work on the subject (Glossary and Manual of Tetrapod Palaeoichnology), joined us for one field-season at Broome (1997). He also examined and verified the unusually large footprint (length >150 cm; 1994, Fig. 3D) that Wedel finds so disturbing.

    4) “… the meta-point, what if the Broome … tracks are underprints?”
    In 1994 it was stated (p. 89) that “… we suspect that many of the tracks exposed on bedding planes [in lagoonal settings] are transmitted prints…”.
    While it’s not recommended practice, I will respond to Wedel’s rhetorical question by posing another rhetorical question. Is it really necessary to state the obvious?
    The footprint measurements we cited are measurements of footprints. They are not measurements of sedimentary structures formed sub-surface. That is, those measurements are from primary moulds (concave epireliefs), impressed directly by the underside of dinosaurian feet, and not from transmitted prints or ‘ghost prints’ (Wedel’s “underprints”).

    5) “The Broom [sic] tracks have gotten one brief note…”
    The “brief note” is 10 pages long (A4, in fairly dense type), with 2 maps, 8 photos and a few dozen references. Wedel cites the pagination as 85-96 whereas it’s actually 85-94 – a trivial point, to be sure, but one which strengthens my growing suspicion that he hasn’t actually looked at the work he disparages.

    6) “… despite the passing of a decade and a half, the world’s (possibly second-) biggest footprints–from anything! ever!–have not yet merited a follow-up paper.”
    “It’s also weird that some of the biggest contenders … have been so little published.”
    I don’t want to waste even more time re-stating the obvious and repeating information that’s already been published. That 1994 paper explains why research on the Broome track-sites proves “a challenging and time-consuming task” (p. 87). I’ll save time by adding only a few supplementary remarks.
    The 1994 preliminary report is just that – preliminary. It’s a rapid survey of sauropod tracks on rocky shore-platforms at discontinuous coastal exposures of Broome Sandstone scattered over a distance of more than 80 km. The geographic range has now been extended to about 200 km. (And, no, there aren’t any track-sites in the interior of the Dampier Peninsula.)
    To paraphrase Wedel: does no one have any conception of the practical challenges and risks attending fieldwork in remote and dangerous areas? It’s not quite as easy as lifting a few specimens off a museum shelf or taking a leisurely stroll over a track-site on dry land. One of the most frustrating problems, acknowledged by every previous investigator, is the difficult and hazardous access. All the coastal exposures (save one) are less than 13 metres thick, and the tidal range is more than 10 metres. Simple calculation (13 minus 10) will tell you that most of the tracks are under water for most of the time.
    Ned Colbert’s memoirs relate his own experiences while investigating theropod tracks (Megalosauropus broomensis) at Gantheaume Point, the type section. (And these, by the way, are comparatively well-known and easily accessible footprints, only a short distance from the town of Broome.) Colbert describes how he and his team had to rehearse in the car-park of the Continental Hotel before they even attempted to secure casts of the theropod tracks. They needed to develop a fast and efficient commando-style operation, just to reach the site, snatch some casts and photos (whatever their quality) and then get out before they were inundated by the rising tide.
    The Broome dinosaur tracks “can only be viewed [or studied] at very low tides, and unless you know the exact time of month when the tide is out far enough, you may miss the opportunity… In fact, without a proper guide you may not be able to find these footprints…” (from a web-site for tourists, 1998).
    There are only brief and infrequent windows of opportunity in which to search out and explore these track-sites, often 30 minutes or less, sometimes as little as 10-15 minutes. And that is only the first and most frequently-mentioned of several major constraints. It takes a long time to assemble a body of data that’s worth publishing, and there’s nothing “weird” about it.

    7) “… if I had access to … a track 1.5 m wide, you can bet that I’d be dropping everything else like a bad habit until I had the gigapod evidence properly written up.”
    No doubt. But I don’t like the thinly-veiled insinuation that tracks have not been “properly written up” in the past, especially when some of my colleagues have risked life and limb to obtain the information that Wedel dismisses as unsatisfactory.
    However, the key word is “properly”. I will release my work on the Broome dinosaur tracks when I’m satisfied that I’ve done the job “properly” – however long that might take and however much my conception of work done “properly” might differ from Matt Wedel’s.

  16. Matt Wedel Says:

    I’m sorry. Sincerely. I really fouled this up, and I have no defense to offer. Thank you for writing to correct me. I will fix the post as soon as I can.

  17. Richard Says:

    I don’t want to be a pain in the neck but those are some pretty serious allegations against you Matt, what really happened?

  18. Matt Wedel Says:

    What really happened is that I screwed up. I misread Thulborn et al. (1994) and took them to task for things they didn’t do wrong. See the apology at the top of the post for further clarification.

  19. Rexisto Says:

    Saludos Tony Thulborn

    It is a pleasure for me to find it on the Web. I ask him about an alleged footprint of nearly 1.7 meters long that is mentioned in a and ornithopod 80 cm.

    Is it possible to know their image and the description of them? I am very interested in the issue of the size of the footprints of Australia.

    Thanks and greetings

  20. Ryan S. Says:

    I watched a discovery channel show with Mr. Wedel in it. Although I respect his knowledge of the subject, I have never understood why these networks insist on using people who clearly have no on-screen personality. Wouldn’t it be better to have someone with a more dynamic personality appear on TV to explain the work that scientists like Mr. Wedel are doing? I can tell you from a viewers prospective, I turned the show off because it was so boring.

  21. Mike Taylor Says:

    That’s Doctor Wedel to you.

    Sorry to hear that science isn’t sexy enough for you. Maybe you should try MTV instead?

  22. Dean Says:

    New 1.7 meter sauropod tracks discovered at James Price Point!

  23. Darius Says:

    I have to ask this:
    How much is there to those 2m prints? Is it just a rounded figure from the 1,7m print mentioned by Thulborn in the DML?

  24. Mike Taylor Says:

    We really don’t know the detail on Thulborn’s giant prints. Unless Matt has something new to add, everything we know is still in this partially retracted 2009 post.

  25. Alexander Says:

    “in which case masses in the blue whale range 150-200 tons ”
    You mean metric tons or short tons?

  26. Mike Taylor Says:

    When dealing with ranges as vague as 150-200, it doesn’t really make much difference whether we mean metric tonnes (most likely) or short tons (10% less). If you like, interpret the range as its widest version, 150 short tons to 200 metric tonnes.

  27. Alexander Says:

    Thank you Mike for answer my question!!! So I want also to ask you about other sauropod tracks. Maybe, you heard about Parabrontopodus distercii tracks? In one source I read: “P. distercii – Meijide-Fuentes et al. (1999). A trace found at the site of Salgar Chairs (Soria, Spain). The average length of the feet is 148.5 cm (4.9 ft), with the largest measuring 165 cm (5.4 ft), making it one of the largest known tracks. It is said that the shape of the tracks is the product of the erosion of the substrate in a particularly compact form, due to the enormous pressure exerted on it by the mass of the animal.”
    So it means length or width of the prints? And, are these tracks bigger than Plagne tracks? What do you think would be approximate size of the dinosaur that made these tracks?
    Also, in your opinion, who is more likely Plagne trackmaker was:
    Brachiosaur or Diplodocid?
    Thank you,

  28. Mike Taylor Says:

    I’m going to leave those questions to Matt, who’s more familiar with sauropods tracks than I am. All I’d say is to treat isolated track measurements with caution, because there are lots of ways tracks can be much bigger than the feet that made them. You really want a proper ichnologist to interpret a given super-sized track.

  29. Alexander Says:

    Also, when you give mass estimate 150-200tons, you mean for both diplo-Diplodocus and mega-Giraffatitan? Also, what was the size the mounted Carnegie Diplodocus from which you got the estimates?
    Thank you,

  30. […] breviparopus skeleton real. Ha, we wish! […]

  31. sublunary Says:

    There are more pictures of Broome tracks here though the paper is mostly about how the tracks affected the substrate.

  32. […] from a two-meter tibia, since destroyed, which could conceivably have massed twice that; and the Broome Sandstone track-maker, known only from footprints, which might have been somewhere in […]

  33. So what do we know about the new tracks from the Broome Sandstone formation? Steve Salisbury led the study, and the tracks are being reported as 5.6 feet in length. Is that feasible? How titanic would something like that be, scaling using similar methods as those above?

  34. Darius Says:

    What I find curious is the size discrepancy we get from different methods.

    Salisbury et al. 2017 reported some crazy huge tracks (at least 175cm by 140cm for the largest specimen).

    Yet the largest “hip height” estimates they made for the owner of these tracks are comparatively modest. They used their newly described Oobardjidama foulkesi trackway to measure glenoacetabular distance and assumed that measurement to be roughly equivalent to hip height, which gave them a ratio of 3.1 between hip height and footprint length. That way they estimated the maker of a 175cm pes print at a hip height (or glenoacetabular distance) of

    This seems like a sound method to me, but how come there is such a large discrepancy with other approaches, such as various previously proposed hip height/pes length ratios?
    Most strikingly Salisbury et al. reported a ratio of 4.8-5.7 in Camarasaurus using a range of plausible metatarsus postures. So based on that, the trackmaker would end up ~55-83% larger than using the proportions derived from Oobardjidama. It is quite a weird coincidence that, especially at the upper end, this is actually closer to twice the ratio than it is to the ratio itself.

    If we use the pes track width of the track in question (140cm) and the figures from Matt’s post, the owner should 59-81% longer than (or 4-6 times as massive as) HM SII. Based on my measurement of Scott Hartman’s skeletal reconstruction ( scaled to the femur length of HM SII, the glenoacetabular distance seems to be about 4.2m, which would give us 6.7-7.6m for the largest Broome Track, while Salisbury et al.’s estimate is “just” 543cm or 29% larger than HM SII, not really all that gigapodous.

    (Also based on the skeletal, acetabular height is a bit shorter than glenoacetabular distance, at ~3.6m, but the height at the highest point of the ilium (~4.3m) or the highest point of the sacral neural spines (~4.6m) are in turn larger. While I’m already at it, the pes length for HMSII seems to by about 100cm going by that same skeletal, so the aforementioned ratio would be ~4.2 in this taxon vs 3.1 in Oobardjidama.)

    A brachiosaurid affinity for the trackmaker was suggested as plausible, so the notion of using Giraffatitan as a proxy should also not be unreasonable.

    Not sure what to make of this at the moment…
    Any thoughts?

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