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Spinosaurus News ~
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 Quote:Benefit of the doubt? It's pretty clear spinosaurus had a pneumatic cervical vertebra, and deep gaps at the back, from FSAC-KK-7280 and FSAC-KK-18122,theres direct evidence supporting it for it for crying out loud, how can spinosaurus have a SG of 1.0 if it had some sort of air spaces? Those vertebrae MAY belong to Spinosaurus but that is not 100% certain. I gave you the benefit of the doubt in assuming it did. Also, have you considered that a density of 1 or more is still possible, even with airsacs, because most tissues as a whole are denser than water? Quote:1000kg/m3 is based on no airspaces? Crocodllians/other specific theropods aren't good for example for spinosaurids because they simply have no air sacs at all, anything with air spaces the density is deceased of 1000kgm/m3, tissues vary in density too. Crocodilians naturally have a density of 1.05 kg/l following Asier Larramendi's works. What I actually did was give the head and neck of SpinoInWonderland's Spinosaurus a density of 0.9 and the rest a crocodilian density to show that even with airsacs an animal can be as dense or denser than water. Quote:Now with SpinoInWonderlands spinosaurus density, which is greatly overexaggerated (this is before Ibrahim et al 2020 incase you forget, MSMN V4047's mass is ten tonnes, imagine with the corrections how heavy it would be!) I got a density of 1 and not 0.9. Read what I wrote above. The head and neck were given 0.9, and the rest 1.05, which ended up in an animal with a density of 1.035. Quote:Going by 1 litre = 1kg for FSAC KK11888 I got it from Scott Hartman's blogpost, which has been clearly linked in my first reply to you. But if we're going to reference the date of publication, Asier Larramendi's work is more recent (2016), and suggests a density of 0.95 for the majority of theropods. This density has been used on significantly more pneumatic animals than Spinosaurus (eg: Aerosteon), and therefore I find it hard to believe a much less pneumatic theropod would have been as pneumatic or less than many theropods with a lot more airsacs. Quote:Speaking of sauropods, I checked Henderson 2003 and it doesn't mention anything on the state of lungs when being calculated specific gravity if anything according to a blogpost, by open of the authors of the paper... Mathew Wedel, https://svpow.com/2009/03/16/brachiosaur...ncomplete/ states he calculated the density of Diplodocus too high he left out air spaces that were too difficult to calculate volume, the volume occupied by the lungs and air sacs, should have been doubled, so if what Larramendi is saying is true, this would compensate however I not fully read Wedel 2005 to double check. That paper got their densities from dead birds that had lungs inflated to the very maximum (a far cry from live, relaxed sauropods with considerably less inflation in theirs), and it failed to take into account that the tissues were denser than water. Also, it should be noted that Wedel has overestimated the airspaces if we follow Larramendi, let me get a screenshot.  *This image is copyright of its original author Larramendi seems to have covered everything on sauropod density that I can think of, and I don't see much reason at this point to doubt a density of roughly 0.9 for sauropods. And therefore, since sauropods are MUCH more pneumatic than Spinosaurus but still have a density of 0.9, I strongly believe Spinosaurus would be a good deal denser than what you suggest. Quote:That is not true, many semi aquatic birds still have hollow bones, terns, gannets, and pelicans, also are divers and have hollow bones, also little grebe a diving bird in the exact reference you gave about loons have a density of 0.86 despite having solid bones (but they do have air sacs), also it has been proved by Henderson et al 2018 that Spinosaurus was unsinkable, being to little dense to dive into water, also before you argue that it would roll, Ibrahim et al 2020 has addressed that argument, the tail fluke would decrease the potential ability to roll and stable the animal during locomotion. There exists a difference between what you and I are using as a reference. Loons do not seem to fly as much as terns, gannets, pelicans, and grebes, and they also seem to spend more time in the water and dive deeper, so it is therefore presumable they are less pneumatic because of it. And I didn't say any airsacs at all would be detrimental, what I am saying is that an animal of 0.833 kg/l is far less realistic that 1+ kg/l given everything above. Finally, keep in mind that simply having airsacs does not prevent a density of 1 or more as shown above. Quote:See this is where I'm starting to get the impression you are cherrypicking, why make it overcomplicated than it should be, just simply apply isometry, a 32% of a 112cm FSAC-KK 11888's skull to get MSMN v4047's skull length of 150metres which is bang on what Therrien and Henderson got, as well as Ibrahim and colleagues. Or it could simply mean the size difference between those specimens is more than 32%. That would also be supported by the size of the corrected model from Henderson (2018) and some other skull reconstructions. Quote:These are multiple experts saying the same thing in multiple papers and not a single image from not even an qualified expert, It doesn't matter if it's peer reviewed or not, what does matter is if it's factually correct. And you have given no evidence suggesting it not to be other than fallaciously suggesting inaccuracy due to no peer reviewing. And show me where I'm taking anything as gospel here? I am aware nothing is truly gospel in palaeontology, so I'm simply endorsing what I find most probable. Quote:So did Ibrahim and Therrien, The morphology of skulls on spinosaurid is drastic, theres too much variation upon spinosaurids, especially posteriorly to get an accurate size, isometrically smaller relatives of a given genus to obtain body length is unreliable because those smaller theropods do not have proportional skull to body length sizes infact scaling actual spinosaurus material ,FSAC KK11888,should be the most reasonable and gives 150cm. Then would you mind explaining exactly why the larger estimates of theropod1 and SpinoInWonderland (especially that of SpinoInWonderland to which your argument of using a different species doesn't apply) are wrong? What you seem to be saying is that they are wrong because they are large, and you don't give any explanation for exactly why the skull reconstructions of either have been done wrongly. Quote:I just did at the bottom Sorry, I'm afraid I can't see this explanation, whatever it was. Would you mind repeating it? Quote:I don't know where you got the idea that Therrien et al 2007 specifies in short tailed tyrannosaurids? Really tyrannosaurids? there's only two that was in the paper at all.How do you know that even either with certainty? In their sample size for the equation, they used Greg Paul's tyrannosaurid skeletals from Predatory Dinosaurs of the World, which happened to have rather short tails. Quote:The digital model itself was 15.5 (based on Ibrahim et al 2014) metres which was rounded to 16 Can I see a source for this? Quote:That skeletal diagram was to show why Mickeys short tailed argument is invalid, simply because they have similar tail lengths are similar size, don't forget unusual theropod body plans like ornithomimosaurs and oviraptosaurs were discredited I don't recall referencing Mortimer's arguments here, therefore I do not see the point of that. Quote:Based on what, even if what your saying is true, 918 kg/m3 is higher than the minimum you said is for spinosaurus which according to you is 0.9, also the limbs of Hendersons spinosaurus was 1.05 SG The minimum density of the neck was 0.9, my estimation of density for the whole animal was 1.034. And despite the dense limbs, Henderson's model is still very likely too pneumatic for all the above reasons. Quote:I checked page 7, barely anything could be taken with consideration barely any sources at all. What on Earth are you talking about? I gave all my sources and methods right there in the post! If there is anything that you need clarification on, just ask. Edit: As it turns out, the skull length on the newest skeletal of the neotype from Ibrahim et al. 2020 is 122 cm, not 112 cm. Based on that and SpinoInWonderland's 186 cm estimate for MSNM v4047's skull length, MSNM v4047 would have been 16.63 meters long and 13.7 tonnes. theropod1's skull length estimate of 177 cm also yields a very large size - 15.86 meters and 11.8 tonnes. The mean of these 2 estimates is basically the same as the corrected model from Henderson (2018), so I'd consider these further support still for very large sizes. |
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