Spinosaurus News ~

[DinoFan83]

Quote:The latest studies would say otherwise, for starters Symth et al provides evidence that they are the same animal, the unique autapomorphies are supposed to be a result individual variation 
(Sigilmassasaurus and S. Aegypticus) are not only the same genus but the same species, actually, even FSAC-KK-7280 is referred to Spinosaurus Aegypticus (not Sigilmassasaurus), the reason why its the most appropriate is quite simple and not the 3864kg is because the 1000 kg/m3 to gain a 3.8 tonne mass is by far too dense and heavy, adult organisms with air sacs don't magically loose them either with growth.

In terms of presence/absence of air sacs, taphonomy cannot play into account like you suggest, because we have two separate individuals with the same pneumatised bone, it would be very coincidental that two separate specimens have pneumatised bone in the posterior cervical vertebra (exact same place!) it isn't even just Spinosaurus, it is a trait of other spinosaurids too.

The high bone compactness occurs from the material obtained from the legs only, specifically compactness in the femoral shaft in contrast to the foramen in FSAC-KK-7280 and FSAC-KK-18122 is from the dorsal vertebra there is a difference in position.

And the possibility of pneumatized bone density has directly came from Ibrahim et al 2020, ironically.

Even Ibrahim et al Wasn't completely not pneumatic, it had a cancellous bone with pores, the femur specifically contains fibrolamellar bone that becomes increasingly cancellous towards the middle.
Cancellous bone does have pores, so it's not completely solid bone like you claim by no air spaces in the 3800kg value.

I find it suddenly weird how your more willing to agree with Ibrahim et al 2014 on a non-pneumatic Spinosaurus but willing to contradict Ibrahim et al 2020 which considers the possibility of a pneumatic Spinosaurus too.

Let's give you the benefit of the doubt here, then. Assuming Spinosaurus DID have a pneumatic neck, we need to take into account that it would have been denser than solely the pneumaticity suggests, as Molina-Pérez & Larramendi point out. As I have linked for the Google Books, they estimate the density of dinosaurs with far more air sacs than Spinosaurus would have had to have already had a density of 0.95, and that crocodilians (the relatively best model for non-maniraptorans, especially spinosaurids) have a density of 1.05 given their lack of airsacs, not simply 1 as one might expect, falling close to the disparity of what the theropod densities are when taking into account and not taking into account tissue density. And SpinoInWonderland's older Spinosaurus supports this well; with a density of 0.9 in the head and neck (as Scott Hartman used without taking into account the denser tissue) and crocodilian-like density in the rest of the animal, the density is overall 1.035. Not to mention, even extant birds (which are the theropods best known by far for being pneumatic) lose their pneumaticity and air sacs when they become semiaquatic. As Wedel et al. 2003 and Schorger et al. 1947 have noted, a very well known diving bird (the loon) has no postcranial pneumaticity at all, just to throw an example out there. And that makes sense, considering being as highly pneumatic is a very large hinder to a diving lifestyle as Spinosaurus is thought to have had. Therefore, based on absolutely EVERYTHING I outlined above, I find a density of at least 1 if not a bit more to be the most realistic by far. And where does Ibrahim (2020) suggest pneumaticity? I am not aware of this.

Quote:According to Lee et al 2014, Deinocherius rivalled the number of airsacs of sauropods, so other particular theropods could easily be exceptions to the general rule also Henderson 2003 actually has sauropod densities lower than the 833kg/m3 of Ibrahims pneumatic spinosaurus.(Apatosaurus's density 818 kg/m3, Diplodocus 814 kg/m3,Camarasaurus 791 kg/m3, Brachiosaurus 796 kg/m3) retrospectively...

Have you read what my Google Books link regarding sauropods stated? The old estimations for sauropod density are much too low because they do not take into account the much higher densities of relaxed animals, they often stem from the most popular publication on density (Wedel's) that overestimated the pneumaticity, and they did not take into account that all the tissues are much denser than water. Therefore I find a density of 0.9 to be more likely for sauropods that 0.791-0.814. And sauropods have significantly more pneumaticity than Spinosaurus, that is an objective fact. (And Deinocheirus would also go up somewhat in density, if it was similarly dense to sauropods it'd be 0.9 or so as they were).

Quote:What you linked was a random image, that's not a source, MSNM V4047 is the largest specimen and even the max size of the skull is still smaller (175cm), SpinoInWonderland isn't a palaeontologist, nor is a image a reliable source and a link on how he got those measurements would be useful too.

What SpinoInWonderland simply did was superimpose the rostrum (which is 98.8 cm long according to the Theropod Database), onto an image of a complete but privately owned Spinosaurus skull, and then given the rostrum length of 98.8 cm, the whole skull ended up at 1.86 meters. Is that really so hard to understand?
Finally, just because he isn't a palaeontologist doesn't mean he can't do good work. As far as I can see he did the best he could due to the fact he used 100% conspecific material.

Quote:As explained MSMN V4047 is a overestimated because Sasso 2005 used different taxon to determine it's length, it is in fact overexaggerated, Hendrickx et al 2016, Therrien et al 2007, Ibrahim et al 2014 also agrees by favouring 1.5-1.6 metre long skull.

Your argument of using a different taxon goes completely down the drain considering that SpinoInWonderland used nothing except Spinosaurus skull material to get 1.86 meters. That's it.
Also, using a different taxon does not necessarily make for an overestimate. Mind explaining just how and why theropod1's reconstruction for example may be overestimated? It uses different taxa but to his knowledge it still holds.

Quote:160cm is an exaggeration because (FSAC-KK 11888's skull is 112cm, basing this with a 32% increase for MSNM 4047 (Supplementary PDF for Ibrahim et al 2014) does not equate to 160cm but less than 160cm, (around 147cm) using Therriens length equation resolves much less than 17m around 12.5metres,  isometrically scaling 32% from 11m (how they got 11 metres is unknown and dubious) neotype also gives a result of 14.5m at max, the scaling increase of FSAC-KK 11888's skull shows a good consistently with Therrien et al 2007's skull length. Henderson 2018 states nothing more than 15 metres in length by the way.

I'll ask this again. Can you explain how an equation based primarily on short tailed tyrannosaurids with no Spinosaurus material in its base sample size is superior to using actual Spinosaurus material? With the latter, that is how lengths of 16-17 meters or so are obtained.
Also, Henderson (2018) states 16 meters as you can see here.

Quote:No absolutely not pre ibrahim 2020 spinosaurus was not 12 tonnes if it had no air sacs/pneumatised bone, how is it pneumatic at all if it's LACKING airspaces and PNEUMATIISED bone?

This isn't pneumatized? Looks like a density of 0.918 instead of 1 to me.

Quote:This model has higher mean density of 918 gm/l

Now sure, it has a higher density. But still very likely not high enough.
Also, would you mind explaining just why the corrected version is so wrong considering I have put absolutely everything I could about it in line with current Spinosaurus knowledge and that is what led to such a high mass? Not to mention it matches the new model of the neotype at the same length almost perfectly, I see that as more confirmation that my corrections were on point.

Quote:''As I have told you before, femoral circumference is not reliable to estimate mass: https://thesauropodomorphlair.wordpress....timations/''

If you actually read what I said, I mentioned why femoral circumfluence cannot be applied to Spinosaurus because of the unique marrow cavity affecting the accuracy of mass estimations (with Persons et al 2019 being referenced which your fully aware of challenging Campion et al's mass equations being applied to S. Aegypticus,and isometry is the only available option which I also quoted from Lakin et al 2019.

My mistake. Point taken.

Quote:Speaking of Mickey Mortimer's criticism, at same scale, Tyrannosaurus (skeletal from Hartman) and Spinosaurus (skeletal from Ibrahim) have almost identical proportional tail lengths.

What does that have to do with this? Reply