Spinosaurus News ~

[tigerluver]

(09-09-2020, 12:43 AM)GuateGojira Wrote:

(06-13-2020, 04:37 PM)DinoFan83 Wrote: Here's a quote from SpinoInWonderland regarding the most recent information on Spinosaurus' size. It should also be noted that due to the tail change, Spinosaurus is a bit shorter than otherwise thought. Scaled 132% from the neotype in Ibrahim et al. 2020, MSNM v4047 is 14.4 meters instead of 15+ for instance. This also affects the other specimens:

"Ibrahim et al. (2020) has a volumetric estimate for the neotype, at 3864 litres. Using a mean density of 0.95 for Spinosaurus gives a mass estimate of ~3.67 tonnes. Scaling up to MSNM v4047 (32% greater dimensions as per Ibrahim et al. 2014) yields about ~8.44 tonnes. It has been argued that the chest of the new reconstruction is too deep, but then the scapulacoracoid is also placed too far back at the chest - these might cancel each other out. Henderson (2018) got a mass estimate too low as the chest they modellled for Spinosaurus was way too narrow than was indicated by the known material."

Now I think a density of 1 is probably more likely as the majority of aquatic animals tend to be neutrally buoyant (EG crocodiles, which converge a lot on Spinosaurus).
Assuming that density, we get:

~3.86 tonnes for the neotype (~10.9 meters)
~8.89 tonnes for MSNM v4047 (scaled up 32%, 14.4 meters)
~9.67 tonnes for NHMUK R-16421 (~14.81 meters), following the discrepancy between it and the neotype that SpinoInWonderland got (link)
~13.66 tonnes for NMC 41852 (~16.62 meters), following what SpinoInWonderland restored for the neotype (51 cm humerus) scaled to the restored size of NMC 41852 fit into the humerus of the Baryonyx holotype (77.7 cm in this image given a length of 46.3 cm for the humerus of the Baryonyx holotype).

Going by this, the average size of the 3 Spinosaurus adults we have seems to be ~15.37 meters and ~10.74 tonnes. That's definitely in pre-2014 Spinosaurus territory, so it looks to me as though Spinosaurus was never really downsized but just got a new look.

Interesting calculations, but the official values at this moment are up to 15-16 meters long and up to 7 tons in the biggest specimen, check these articles:

https://peerj.com/articles/5409/
https://www.nationalgeographic.com/scien...-swimming/

I am going with the official data for the moment. 

*This image is copyright of its original author

The Henderson study was not very evidence-based relative to Ibrahim et al. The author assigned an arbitrary density then "proved" Spinosaurus was too buoyant to dive. Just noting his as most people don't seem to understand the methods in dinosaur paleontology are much more subjective and inconsistent than mammalian paleontology. Official values aren't the end all be all, remember M. kabir is still 490 kg in the literature and the methods to produce that mass are much more objective than GDI. Reply