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DrScottHartman β Diplodocus (NOT Seismosaurus) longus
Published: 2014-07-20 05:24:26 +0000 UTC; Views: 8155; Favourites: 99; Downloads: 0
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Description
I'm going to take a hard stance on this - there is no such thing as Seismosaurus, or even Diplodocus "hallorum". Nope, nada, never. It's a somewhat larger specimen of the also enigmatic D. longus (which is actually the type species for Diplodocus!), and there's nothing wrong with that. Long time viewers of my website (or of my professional publications) will know that this isn't a new skeletal, I've just updated it to current standards and decided to post it to DA since I haven't put anything up here in a while during a very busy summer.Anyhow, for those of you who like such things, I've rechecked the scaling on everything (including the restored parts) and this specimen of D. longus is a hair under 32 meters in length, with is very respectable, though no where near the crazy estimates published in the 1990s.
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Comments: 49
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I thought the "Seismosaurus" remains are now called Diplodocus hallorum?
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When my colleagues and I sunk it in our Supersaurus paper we put it into D. longus, and I'm not willing to give up that fight just yet. But since quite a few people think D. longus might not be diagnostic, D. "hallorum" may end up being the winner. We'll see.
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I guess. Diplodocus was already thought to reach ~29 meters, so it's three meters longer. That's not trivial, but it's no where close to the original estimates of the size of Seismosaurus, which were simply wrong.
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First, I really appreciate the compliment. Second, you may need to get out more...
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Now seriously, how different are the Diplodocus species?Β
I saw your Diplodocus species comparision years ago but it doesn t show the D.longus skull or any cervical vert but I m quite sure that are known...
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I'm seen real Diplodocus longus's back vertebrate pieces are now displayed in New Mexico Museum of National History in Albuquerque, NM.
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Yes, and tragically they are embedded in some sort of cement/faux stone stuff.
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Hello. Needless to say that I find your illustrations absolutely amazing. I was wondering however how you go about these kind of reconstructive illustrations (as with this Diplodocus.
Do you base the Linework of the bones on a single picture, that you trace (a photograph maybe) or do you envision the whole "bone construct" from scratch? I'm very interested in paleontological illustration, unfortunately they don't teach it at our school and we have no other courses that really compare.
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Hi Sais, thanks for the kind remarks! Someday I probably need to do full tutorial (or rather a series of tutorials) on how I do skeletal reconstructions, but I fear that day is still some time off. The short version is that each bone is reconstructed individually from measurements, photographs, and once in a while (if really necessary) from line drawings. You can't simply trace the bones as that can itself cause problems with the bone (including when the fossils themselves are incomplete, damaged, or distorted) and from the technique (you need rules on where your drawn lines go relative to the margins of the fossil, etc). A lot of the time is spent just scaling everything to make sure the bones are the correct proportions (relative to one another as well as to other parts of the bone if it's a complex shape). Then I assemble them - I don't know if there's a shortcut to doing the latter step correctly than to simply read the technical literature on the subject you are reconstructing. I was lucky in that on top of reading (and contributing) to the literature I also helped mount almost two dozen skeletons at the Wyoming Dinosaur Center - there are a lot of things that look ok in 2D that you realize aren't possible when you have to put together physical 3D objects.
But again I don't know of any single resource where that sort of information is available - sorry!
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Thank you for the description. It may be short, but I find it very useful
Knowing how to go about starting this kind illustration already helps a great deal. Your website also contains some great pointers and reference, so thank you for that as well
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You're welcome. And good luck!
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Really cool! And what about the Guanlong skeletal?
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Still in progress.
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This actually makes me curious, how do paleontologists tell the difference, or decide the difference, between two species within one genus vs variations within a species?
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Well genera are admittedly arbitrary (how different species have to be to merit their own genera varies from subdiscipline to subdiscipline). But to be a different fossil species there need to be some characters (at least 1!) to separate them, and there doesn't appear to be any between Diplodocus longus and "Seismosaurus".
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Alright thank you. That was always something I wondered, since with fossils we don't usually have things like skin and behavior that can help distinguish between modern species.
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Ouch! Right in the childhood! But seriously, I've known about this for a while, and these days even popular books tend to depict the titanosaurs rather than the diplodocids as being "the biggest EVER".
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Diplodocids (and specifically Supersaurus) still hold the record of the longest dinosaur (at least among those complete enough to estimate with any certainty).
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Just wondering, did you do any lengthening of the neck as compared to a vanilla Diplodocus c.? Β The guys at SV-POW write:
Mere isometric scaling would of course suffice for larger animals to have longer necks, but Parrish (2006, p. 213) found a stronger result: that neck length is positively allometric with respect to body size in sauropods, varying with torso length to the power 1.35. This suggests that the necks of super-giant sauropods may have been even longer than imagined
Taylor MP, Wedel MJ.Β (2013)Β Why sauropods had long necks; and why giraffes have short necks.Β PeerJΒ 1:e36 dx.doi.org/10.7717/peerj.36
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That was a general phylogenetic trend across sauropods, not and absolute one (e.g. Supersaurus isn't as massive as the larger titanosaurs by a fair bit, but has a longer neck). And we know how long the neck of an adult Diplodocus is, so there would be little reason to enlarge this one.
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I was referring to neck length over body length, not mass. Β I'm also speaking in an ontogenetic sense. Β More mature individuals also tend to increase neck length more rapidly than body length. Β I just applied the formula and it would only add a about 3/4 of a Β meter.
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Ah, but Parrish did not derive his scaling factor from ontogeny, it's for between-species comparisons and in this case we already are pretty certain how the neck scales. It's true that sauropods do show an increase in neck length during ontogeny, but that doesn't imply that the biggest adults within a species will have disproportionately longer necks, at some point adult growth generally becomes isometric.
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Ok, is there any information on neck lengths of smaller Diplodocus specimens? Β (My hopes aren't high, lol)
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The very complete specimen of D. carnegii has been known for more than a century.
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Haha, other than thatβ¦.
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Nice to see more of your works here again! But Seismosaurus, is a loose for the nice scientific names...
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It's actually a great and very evocative name - indeed, Seismosaurus and Brontosaurus are almost the same name (both named because the animals would have presumably shaken the ground on which the walked). That doesn't make it scientifically valid though - that requires a higher degree of evidence than the coolness of the name.
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Yes, I know, but is curious how this evocative names are used in dubious sauropods like Titanosaurus or Atlantosaurus
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is there any hope seismosaurus or brontosaurus will be reused for some future genera of newly discovered sauropods or have these names fallen down the abyss of unusability by now? I gather reusing those names would/could cause confusion, but then again, why not use them? they are technically free for grabs now, aren't they?
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Joeabuy is right - for better or worse genera cannot be reused according to the laws of zoological nomenclature. It IS conceivable that Brontosaurus could turn out to be its own valid genus, but from what I've seen there's little hope for Seismosaurus.
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all right. That's what I thought.
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I can't say this with any degree of accuracy, but if I recall, the rules of nomenclature (naming living things) state that once a junior synonym has been tied to another, it'd be confusing for future scientists to name them if they were recycled UNLESS that which they originally assigned to another genus or species was in fact a different animal this whole time, in which case, the genus is made valid again.
IIRC, there was a possibility that Brontosaurus could become a valid taxon again if research points out that at least one of the Apatosaurus species is significantly different from the others to warrant being placed in a different genus, but I might need to look into this a lot more, so take it with a grain of salt.
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All right. thank you for your thorough and civil response!
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Awesome. When I was very young, I learned of Diplodocus that it was "the very longest" of all dinosaurs. As time went by, it fell down that scale, and became smaller and smaller compared to other "more epic" species.Β
As an adult, I realize two things: Firstly, and perhaps most importantly, actual living dinosaurs didn't give a shit about our estimates and expectations. Like, is Tyrannosaurus 11, 12 or 13 metres? In reality, it was all those and more, depending how big and fat it was. Simple as that.Β
Secondly, what you just said - Seismosaurus is Diplodocus (because we define it to be 
In the end, it doesn't matter that much, cus Diplodocus was effin gigantic
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Bigger than a herd of horses!
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My political leanings do not allow me to accept that there is no such thing as seismosaurus.
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Lol. I can't help you then, I only deal with what the facts can establish
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Between 38 and 50 meters.
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Wow, thats Pretty Big.
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That's what she said.
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I'm glad I didn't have to say it.
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You have to maintain an air of paleontological dignity.
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