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DrScottHartman — Majungasaurus - redux

Published: 2008-06-06 22:39:01 +0000 UTC; Views: 36719; Favourites: 286; Downloads: 0
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Description Finally! After an eternity of revisions and attempts to reconcile the proportions of specimens of different ages that frequently didn't overlap, I feel confident I've nailed the general proportions.

With generous aid from several people ("credits" below) I figured out that the legs weren't actually too short in my original skeletal - in fact I ended up making them too long in my most recent attempt. Instead, the vertebrae and ribs based on UA 8678 (that would be the cervicals, dorsals, sacrals, and 5 anterior caudals) were scaled up too large.

That's an important distinction, as scaling them down had a chain-reaction on the relative size of the head, pelvic and pectoral girdles, etc.

It's still a strange and somewhat low-slung theropod, but nothing like my previous attempts. I should note that there weren't any mathematical scaling errors - rather, the way I chose to reconcile the axial series of UA 8678 to the larger tail and head of FMNH PR 2100 was wrong (the latter has proportionately taller neural spines, which is probably an ontogenetic feature).

Obviously newer data could require some nips or tucks, but I honestly think you are safe to illustrate Majungasaurus now. I know I plan to!

Special thanks (in alphabetical order) go out to Matt Carrano, David Krause, Adam Pritchard, and Scott Sampson, all of whom who provided excellent critiques and made this version possible (not to mention the research and publications the restoration is based on).

Now I'm going to go find a bottle of champagne to pop...
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Comments: 164

DrScottHartman In reply to ??? [2011-09-02 04:59:55 +0000 UTC]

It's like Brontosaurus and Apatosaurus - both names apply to the same animals, and Apatosaurus came first, so it has priority.

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RiotLizard In reply to DrScottHartman [2011-09-02 19:49:26 +0000 UTC]

i always thought it was brachiosauras and brontosauras, same dino, different names

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DrScottHartman In reply to RiotLizard [2011-09-03 22:50:13 +0000 UTC]

No, Brachiosaurus is a macronarian sauropod, while Apatosaurs/Brontosaurus is a diplodocid. Brachiosaurus has upward-sloping shoulders (amongst a host of differences) while diplodocids are very horizontal in their orientation.

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RiotLizard In reply to DrScottHartman [2011-09-03 22:51:14 +0000 UTC]

boy, you're a dino expert ok i get it now, thanx

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rhys12345 [2011-05-26 08:12:26 +0000 UTC]

that thing looks like it has dwarfism, how could somethiing's legs be that short?

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bensen-daniel In reply to ??? [2011-03-01 06:19:55 +0000 UTC]

Wuh. I can see why it's controvercial. Something that long with legs that stubby LOOKS wrong. Doesn't mean it is, though. I remember how surprised I was when I saw Sue at the Field Museum and noticed how low to the ground she was, too. I guess it makes sense for a big animal to have a low center of gravity, but what does this mean about running speed?

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acepredator In reply to bensen-daniel [2015-05-11 01:24:10 +0000 UTC]

I don't think this thing could run.

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tyrantslayer In reply to ??? [2011-02-27 07:26:20 +0000 UTC]

a few paleontologists have suggested that it was semi aquatic... explaining the squat stance... it probably would not have to have been very fast either because all of the prey items in it's habitat were relatively slow moving creatures... however, definately not an evolutionary disaster as many posters seem to believe.

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DrScottHartman In reply to tyrantslayer [2011-02-27 19:01:49 +0000 UTC]

By definition things don't evolve if they don't work reasonably well in a local environment. I'm still not convinced by claims of a semi-aquatic lifestyle, but given the lack of any obvious correlate ecomorph I'm happy to at least entertain it as one of the working hypotheses.

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tyrantslayer In reply to DrScottHartman [2011-02-28 05:46:17 +0000 UTC]

well, obvioi'm not very much for the idea of it being semi aquatic either. you'd think it would have evolved a deeper tail to help it out in the water.

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amorousdino In reply to ??? [2011-02-23 10:32:30 +0000 UTC]

I rest my case...

Mamma Nature was doing crystal meth when she was designing these guys... its like a Carnotaurus had a baby with a dachshund...

big wiener dinosaurs....

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DSil In reply to ??? [2011-02-22 23:32:31 +0000 UTC]

The dachshund of therapods. What the hell would it do if it fell over?

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DrScottHartman In reply to DSil [2011-02-23 03:55:13 +0000 UTC]

Whimper? I'm sure it could flail until it got its feet back under it, but I doubt it was either fast or graceful in the process.

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KatePfeilschiefter In reply to ??? [2011-02-22 23:24:20 +0000 UTC]

He looks like someone held and pulled him by both ends like taffy. Certainly a very interesting therapod. I wonder how he lived.

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DrScottHartman In reply to KatePfeilschiefter [2011-02-23 03:59:22 +0000 UTC]

Wouldn't it be interesting if the short legs were due to something that couldn't be predicted just from the anatomy? Like if it regular hunted in a closed canopy forest that was unusually short, and this let an otherwise large animal move around unobstructed?

I'm totally pulling that from where the sun don't shine, but it does illustrate the challenges of inferring behavior without a better environmental dataset.

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Boverisuchus In reply to DrScottHartman [2011-02-23 10:30:42 +0000 UTC]

the classic example of which is the Water Dipper Bird, skeletaly it's just a normal bird, but in life, it's aquatic.

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KatePfeilschiefter In reply to DrScottHartman [2011-02-23 05:16:11 +0000 UTC]

indeed, though in cases like that the importance of plant and dung fossilization is renewed.

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cryptidsaurian In reply to ??? [2011-02-22 21:25:34 +0000 UTC]

I've always thought of this guy as an aquatic ambush predator, although i'm not sure of the flexibility of the tail so I have no idea whether it could actually swim.

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DrScottHartman In reply to cryptidsaurian [2011-02-23 03:57:25 +0000 UTC]

That could get some quick reinforcement if someone did an isotope analysis of the bones. The aquatic ambush predator isn't my first vote...but then I wouldn't rule it out either.

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cryptidsaurian In reply to DrScottHartman [2011-02-23 12:37:39 +0000 UTC]

hm ok, well I think said it was plausible as well and that it wasn't his first bet either.

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Desmodeus In reply to ??? [2011-02-22 19:19:04 +0000 UTC]

Looks like some god uploaded the file to a site that stretches images to fit a set a width!

I can't imagine it being particularily agile. :/
Perhaps ambush predator? *shrug*

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r-heinart In reply to ??? [2011-02-22 17:26:24 +0000 UTC]

Wonder how'd he run, Powerful legs, but short, to said the least.

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DrScottHartman In reply to r-heinart [2011-02-22 17:56:47 +0000 UTC]

Honestly I doubt it could run. The legs are very powerful, but don't appear to be long enough to get the body into a full suspended ballistic phase.

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r-heinart In reply to DrScottHartman [2011-02-22 18:15:13 +0000 UTC]

Very top heavy, it could waddle at best.

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Skull-Island-Master In reply to ??? [2011-01-31 15:00:18 +0000 UTC]

That thing was so strange,

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r-heinart In reply to ??? [2011-01-20 17:30:06 +0000 UTC]

Very strange, very low-to-the-ground. Not my favorite Abelisaur either . . .

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cryptidsaurian In reply to ??? [2010-11-24 02:21:59 +0000 UTC]

i have a question with the bones being of from what i hear of different aged individuals, are you sure the legs were that short? i've seen 2 others with legs that were just slightly smaller than yours but it looks like with legs even this big it would have fallen on it's head. also, do you think this animal may have hunted like a modern croc, it seems (just my opinion) that it would have been a powerful swimmer, at least for a theropod.

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DrScottHartman In reply to cryptidsaurian [2011-01-20 22:16:21 +0000 UTC]

Oops, I meant to answer this long ago. I have two answers to the question:

1) I'm sure I cross scaled between individuals correctly, as I redid it perhaps a dozen times out of frustration, thinking "this can't be right!"

2) I'm not at all sure that all the individuals referred to Majungasaurus actually are the same species. In that case it may be that I'm combining animals with very different proportions. But we'll have to wait for additional finds to be published before we'll know this for sure.

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Coelophysis In reply to ??? [2009-11-11 02:08:08 +0000 UTC]

Since it was so low to the ground, I wonder if Abelisaurids primarily prayed on smaller dinosaurs as opposed to the huge sauropods of Gondwana.

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DrScottHartman In reply to Coelophysis [2011-02-23 16:01:16 +0000 UTC]

Gotta agree, they don't strike me as sauropod killers either.

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DOTB18 In reply to ??? [2009-09-02 23:02:48 +0000 UTC]

Could it be possible that this guy was semi-aquatic? Perhaps the short legs made it more hydrodynamic. And if I remember correctly, ceratosaurians had more flexible tails than tetanurans. I can imagine this guy undulating along a river like a crocodile.

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DrScottHartman In reply to DOTB18 [2009-09-30 02:41:22 +0000 UTC]

I think the most likely possibility is that there are two different genera mixed up in the specimens referred to Majungasaurus. That said, if the short legs stayed then yes, I would consider the possibility that it spent some time marching through the shallows.

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Afrovenator In reply to DrScottHartman [2010-08-21 00:14:39 +0000 UTC]

Sorry for replying to a message that is nearly a year old, but what are your reasons for suspecting that there might be two genera mixed up in the specimens referred to Majungasaurus?

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DrScottHartman In reply to Afrovenator [2010-08-21 04:19:35 +0000 UTC]

Because when I was combining remains from different specimens there are incompatible proportions in the axial column. It turns out that not long after I wrote that someone published a paper showing that there are two clear morphs of teeth in the formation also, so that would seem to reinforce the idea quite strongly.

There is a specimen that has been excavated (it's mentioned in the JVP monograph) that is more complete, including hind limbs, so that should shed further light on the issue when it is described.

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Dilong-paradoxus [2008-07-28 21:48:16 +0000 UTC]

Is that really how short the legs were? Could they actually support the body?

Is something fishy here, or is it just me?!

Anyway, nice skeletal!

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DR-Studios In reply to ??? [2008-07-04 00:30:42 +0000 UTC]

I agree the body is oddly elongate for a theropod. Cervicle ribs seem very robust though...

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Qilong In reply to ??? [2008-07-02 11:04:56 +0000 UTC]

Y'know, I'm beginning to suspect the legs show either one of two habitual possibilities.

It either crouched a lot an brought it's body lower to the ground, or was a runner.

Or the legs were short but powerful for digging.

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Paleo-Orca In reply to ??? [2008-07-01 23:29:54 +0000 UTC]

Definitely a strange looking and built theropod :0

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EmperorDinobot In reply to ??? [2008-07-01 23:13:55 +0000 UTC]

Would have been nice to keep the other one, too. Like, Majungasaurus I and Majungasaurus II.

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DrScottHartman In reply to EmperorDinobot [2008-07-02 05:53:59 +0000 UTC]

Yeah, you're probably right. Maybe when I get the chance I'll upload it again and lable them as such.

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EmperorDinobot In reply to DrScottHartman [2008-07-02 07:23:02 +0000 UTC]

Ah good.

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Sainte-Vincient In reply to ??? [2008-07-01 22:12:19 +0000 UTC]

LOL The Dachshund dino! I agree that it seems unlikely that the center of gravity would've allowed this bugger to run with any alacrity. Walking just doesn't look as weird.

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CBSorgeArtworks In reply to ??? [2008-06-13 20:00:59 +0000 UTC]

Long majungasaurus is loooooong :3

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nemo-ramjet In reply to ??? [2008-06-11 16:21:21 +0000 UTC]

[link]

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Zippo4k In reply to ??? [2008-06-11 11:19:30 +0000 UTC]

I's got such short legs but a long body... and yet it's clearly still a biped... weird...

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SADistikKnight In reply to ??? [2008-06-09 16:57:33 +0000 UTC]

Very very strange....im still trying to wrap my head around how it moved about without falling over...

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DrScottHartman In reply to SADistikKnight [2008-06-12 00:08:31 +0000 UTC]

Remember that it couldn't stand in the position I've illustrated it in; the running phase is inherently unstable (that's the point in a biped). Maybe I'll whip out a standing pose to upload tonight...

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TopGon In reply to DrScottHartman [2011-02-22 17:07:23 +0000 UTC]

We need it!

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SADistikKnight In reply to DrScottHartman [2008-06-12 19:33:12 +0000 UTC]

Ahhh that would be very interesting, again considering its very unusual proportions

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maniraptora In reply to ??? [2008-06-09 14:13:22 +0000 UTC]

The neck is so long, and the legs very short... strange creature!
Great work, as usual!

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