Super Spinosaurus?
June 28, 2013
In the past I have been skeptical of claims of 50+ foot Spinosaurus specimens - and with how little we know about the tail length in Spinosaurus there is still reason for caution.
That said, science is always based on data, and sometimes the data isn’t what you expected. I was reminded of this once again recently after I tweaked the scaling of elements in my Spinosaurus skeletal reconstruction. The “main” skeletal seen above (the fully restored version is in the theropod gallery) is based on a composite skeletal of the type specimen and other various referred bits. Previously I’d had the mandible scaled up too much by about 6%. After correcting I measured and sure enough, a nice 14m (46 foot) long beast.
Now please use some caution here: as you can see the composite skeletal is missing large swaths of bones. I have filled those in with bones from other relatives (e.g. Baryonyx and Suchomimus), but there’s definitely some uncertainty here. Of particular note, tail length varies quite a bit in dinosaurs (as demonstrated recently by Dave Hone), and I would feel a lot better about estimating the length if we had some more Spinosaurus tail vertebrae.
Still, unless you restore an almost comically long tail the type specimen of Spinosaurus was less than 50 feet. Ah, but that’s not the largest specimen! The biggest specimen referred to Spinosaurus is MSMN V4047, a giant snout that Dal Sasso et al described in 2005.
Assuming that the composite is scaled correctly and that the giant MSMN specimen scales up isometrically (which seems probable) then it would be in the range of 15.6 meters (51 feet) give or take. That’s one long theropod we are looking at! Given our margin of error it’s entirely possible that the MSMN specimen is actually 48 feet (or 55 feet!), but assuming it had proportions similar to that of other spinosaurids, then it seems clear that 50 foot lengths were most likely attained.
Of course length is just one estimate of size, and mass is generally considered more important. And here things get interesting. Check back this weekend for a closer look at how much Spinosaurus may have tipped the scales in life.
22 comments
Mr Scott yours skeletal are amazing!
But I have a couple of questione for you...
First the skull of MSNM V4047 con be estimated in 150/160 cm after Irritato and so the specimen was long 14 meters or a little more (14,2 by my hand).
Second after Carrano et al (2012) revaluted the Giganotosaurus holotype, band their reporter a 1,36cm femora band a less the 150 cm skull, in that case the entire skeleton would be shoryer Ethan 12 meters.
Su is almost complete band sue talk forma herself (amazing work)
Contra Therrien & Henderson (2007) there's no way to make the skull of MSNM V4047 150-160cm long, that'll make the posterior part of the skull comically small, I've seen people try, what is preserved of the rostrum is already 98cm long and is missing the most posterior parts, it's just not possible and by the way, the skull at 175cm is already based on Irritator.
That Carrano et al. (2012) found the femur to be 136.5cm instead of 143cm has no effect on the overall size of the animal, Hartman doesn't scale the whole animal on a single bone, the same goes for the skull, also we have to know what Carrano et al (2012) means by skull length, they said that just by giving the skull of SMG DIN-1 a premaxilla based on Giganotosaurus and Mapusaurus it'll make it 142cm long, using the illustrations in Sereno et al. (1996) I can say with confidence that what Carrano et al. (2012) means by skull length is more commonly known as dorsal skull length or condylobasal skull length, making the premaxilla more like giganotosaurus like they said reduced that measurement to exactly 142cm but the greatest length was 155cm (instead of 160cm), I'm pretty sure that the same goes for Giganotosaurus ~1.4m dorsal skull length and 1.53cm greatest skull length.
I'm Italiano, and I have personally saw the Spinosaurus rostrum, it s huge, but very misunderstud.
The premaxilla si 82 cm long and at the distal end of the fossil start the anteorbital fenestra, and so based on Irritator the full skull reach 150/160 cm.
The holotype of G.carolinii after Carrano paper is long 11,5/12 m, a very big teropod and at least only zone meter less than mr Hartam (excellent) recostruction.
At the end I trust more Carrano paper than Coria e collegues one, at least 'cause it s more recent.
Thanks for the comments Marco - I agree that Irritator at least suggests a smaller head. That doesn't necessarily imply a smaller length of the whole animal though, as unless I'm mis-scaling the rostrum against the type specimen itself (e.g. the posterior head might get smaller on both reconstructions, but that wouldn't affect the total length much) then the MSMN specimen should still be around 6-9% bigger than the type.
I am aware of the Carrano et al measurement - it may well be correct, but luckily it only impacts hip height by a small amount (a 4% shorter femur is not even a 2% margin of error for the overall leg length) and shouldn't otherwise impact the Giganotosaurus reconstruction.
Excellent observations!
I'm not 100% convince about the Irritator scaling either way, but you are right about the Giganotosaurus measurements not having a significant impact - and as you note the skull is not complete, so any measurement of it is dependent on the assumptions made for the missing pieces.
Thanks mr Hartman, and your skeletal recostruction are always excellent !
To better evaluate this issue I restored Irritator's skull and then tried to shoehorn in onto the Spinosaurus material more literally, to make it as Irritator-like as possinle. I don't think I got the results you were expecting - in particular the distance of the external nares from the antorbital fenestra are not at all the same between the two, and the depth of the rostrum (or possibly the degree or nature of the elongation of the snout) must be different between them as well. Perhaps I'll write up a post on it while I do some number crunching for the mass estimate post?
The preserved part of the rostrum of MSNM V4047 is 988mm long according to Dal Sasso (2005) from where did you get 82cm?.
About Giganotosaurus, just because its more recent doesn't mean its better, specially since Carrano et al. paper is a phylogenetic analysis of the whole of none coelurosaurian tetanurans not a Giganotosaurus osteology that also aims to provide a whole body reconstruction of the specimen, again, if the femur is shorter, it doesn't mean everything else is smaller, it just means that the femur is shorter, Mr. Hartman didn't made his reconstruction based on Coria's paper, I have it and its atrocious for that purpose haha I think he mentioned on deviantart that he made it for a museum that had in exhibition a mount of the holotype, he probably got access to said mount. Even if the skull can be squeezed to 1.4m in greatest length (which I don't think is what Carrano et al. meant) it would only make Mr. Hartman's reconstruction 12.3m instead of 12.4m not a whole meter shorter as only the length of the skull would be affected.
I said 82 cm si the lenght of premaxilla not of the rostrum.
About the size of Giganotosaurus I agree with you about Coria's paper and after Carrano's one, I consider a 11,5/12 meters a better est. of the G.carolinii holotype.
PS-I very like the mr Hartam skeletal, nothing against it
Sorry I misunderstood you, I haven't realized that the premaxilla extends so far over the maxilla.
Per niente: l'accorciamento del femore ha un impatto solo sull'altezza dell'animale (da 3,5m a 3,4m), e l'accorciamento del cranio toglie solo 10 centimetri alla lunghezza, e ciò renderebbe l'animale lungo 12,3 metri...in nessun modo MUPCv-ch1 è più breve di 12 metri. C'è da aggiungere che Carrano non è neanche il miglior studio in circolazione, mi fido più della ricostruzione di Hartman.
Can't wait for the next updates,I read on the facebook page that over 15 tonnes is out the question, so around 10 right? anyway I will probably get my answer in the next posts. :D
Soon(TM)!
Very interesting because Irritator is phylogenetically more affine to Spinosaurus than Baryonyx band Suchomimus..
Just another little thing, in Milano natural museum there is a picture of the skull (you con sede it un many photos of the rostrum),band it s 156 cm more or less based on the esame rostrum.
What do you think a out it?
For sure Irritator is closer to Spinosaurus than either are to baryonchines, but they still lived on different continents and possibly at different times, so I wouldn't expect them to be clones either. My current reconstruction of the MSMN snout leads to a skull of 162-164 cm in length, but if I enforce a totally Irritator-like back end it's closer to 158 (mostly because of the more vertical quadrate). I should note that these are premax-quadrate measurements, not a maximum length measurement (which would actually be from the snout to the sagittal crest as I've restored it).
None of this changes my overall scaling of the the length or mass of Spinosaurus.
I agree, 158 cm forma the full skull is a measurament very similar to mine, and anyway Spinosaurus was a >14 meters beast.
At the end on the NET I saw a comparasion size of T.rex G.carolinii e S.aegyptiacus (with yours skeletals and very similar to this one) with a little smaller Giganotosaurus (Like Carrano sensu) and a very similar Spinosaurus.. It's that yours? That look very good (mostra because yours work I suppose)
Ti riferisci a questo?:
http://lh5.ggpht.com/-owzWD...
No, è stato fatto da Verdugo, un fanboy prevenuto di Tyrannosaurus rex che pensa che tutti i Teropodi sono inferiori a Tyrannosaurus rex. E la lunghezza di quel MUPcv-ch1 è inferiore ai 12 metri solo perchè lui ha mostrato la lunghezza assiale, ovvero sopra le curve, in realtà l'animale lungo le curve e ben più lungo, 12m+.
Don't take Verdugo seriously, he even stated that the maximum length of Tyrannosaurus should be 14+ meters based on...UCMP 137358. facepalm
Also he thinks that Cau's ~14.4 meter standing length(~15 meters axial length) estimate debunks the higher estimates.
Well, I don't know who Verdugo is, and yes fanboys are not impartìal guys, but this picture is quite interesting:
1)a near to 12 m axial lenght for T.rex give us a 12 and samewhat animal (=Sue), so the skeletal is outdated but generally OK.
2)the Spinosaurus have a 150/160 cm skull and si in between to the 2 Mr Hartman est. with a lenght of 14/15 m., a good estimation of course.
3)Giganotosaurus is 12m long, 11,5 axial lenght, it's clearly the holotype band just a little bit small but nave the Carrano's dimension of cranium band femur.
So similar to mr Hartman zone band quinte interesting too....
Mr Hartman, II've got a question,
rumours have been floating around about supposed new material, including hindlimb bones having been found of Spinosaurus (the big, short-legged italian model supposedly based on them). An aquaintance told me these were going to get published soon (ie the past summer). Do you know anything about the issue?
I look forward to an analysis that (I am guessing) will downgrade some of the ridiculous weight estimates (15-20 tons) that have been bandied about. My quasi-educated guess is that this Super Spinosaurus weighed no more than 11 tons max. Now I'm on the record.
Very Interesting Article!
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