Dinosaurs and other prehistoric creatures

[Blacklabel]

I'm getting warmed up to this newer vision of the Spinosaurus.

It's essentially a really badass aligator from hell..

[DoomRulz]

Top-heavy, but not a preferred or obligatory quadruped like the initial reconstruction suggested. It's a good stance for occasionally using those front limbs to help drag itself out of a muddy shoreline, as suggested by one of Funkei's links a little while ago.
Kind of a shame though, a quadrupedal theropod would have been pretty damn cool.

Interesting to note, Ibrahim/Sereno etc's study states that the sail bones are poorly vascularised, and it seems they don't think it would have been used as a heat regulator.
Not sure I agree with that, the bones' solidity is part of the animal's aquatic adaptations, and we don't know enough (well, anything) about the nature of the soft tissue that surrounded the spines.

Quadruped or not, being top heavy to me would be a serious disadvantage in the long run. Let's assume for the moment that Planet Dinosaur was 100% right when they said the area in which Spino lived was prone to seasonal droughts. I don't see it taking down Ouranosaurus or even fighting Carcharodontosaurus if it can barely lift its head above the ground.

[Vertigo]

That's probably why the line didn't go any further. The isotope analysis does suggest that the very last known spinosaurids didn't spend much time in water, and Spinosaurus in particular just wasn't well-adapted for a terrestrial lifestyle.

I don't expect Carcharodontosaurus would particularly want to get scrappy with Spinosaurus (the latest estimates I've heard are over 10 tonnes for the adults), but even if the spinos were able to scavenge food from other theropods, it'd be very hard for them to subsist on that alone.

[DoomRulz]

That's probably why the line didn't go any further. The isotope analysis does suggest that the very last known spinosaurids didn't spend much time in water, and Spinosaurus in particular just wasn't well-adapted for a terrestrial lifestyle.

Was there further spinosaurid evolution beyond Spinosaurus?

I don't expect Carcharodontosaurus would particularly want to get scrappy with Spinosaurus (the latest estimates I've heard are over 10 tonnes for the adults), but even if the spinos were able to scavenge food from other theropods, it'd be very hard for them to subsist on that alone.

I'd hold off on estimates, until we have something more concrete. Some folks are saying 20 tons and I don't believe that. It's all wild speculation.

[Cvalda]

dinosrs

[Vertigo]

That's probably why the line didn't go any further. The isotope analysis does suggest that the very last known spinosaurids didn't spend much time in water, and Spinosaurus in particular just wasn't well-adapted for a terrestrial lifestyle.

Was there further spinosaurid evolution beyond Spinosaurus?

Spinosaurus and poorly-known Brazilian giant Oxalaia were concurrently the last definite spinosaurids.
It's unclear how closely related the two were - Spinosaurus seemed to be an extremely long-lived genus, evolving right as the two landmasses split, but Oxalaia appeared 12 Ma after the split. It may be a relict Spinosaurus population, or it may be a massive baryonychine; hard to tell from a braincase and a scattering of teeth.

There are tooth finds attributed to spinosaurids for another 12 million years, but there's a history of spino teeth being confused with those of crocodilians, so they may not be valid. Spinosaurid evidence is generally extremely poor - it's basically just Baryonyx, Suchomimus, Irritator and Spinosaurus that are known in any significant detail.

[P.Funkei]

That's probably why the line didn't go any further. The isotope analysis does suggest that the very last known spinosaurids didn't spend much time in water, and Spinosaurus in particular just wasn't well-adapted for a terrestrial lifestyle.

I don't expect Carcharodontosaurus would particularly want to get scrappy with Spinosaurus (the latest estimates I've heard are over 10 tonnes for the adults), but even if the spinos were able to scavenge food from other theropods, it'd be very hard for them to subsist on that alone.

Perhaps Spinosaurus primarily subsisted off of aestivating fish during the dry season (in fact, Andrea Cau, author of the theropoda blog, has posited the same hypothesis.). 

Also, here's another researcher with some reservations about the new reconstruction from Ibrahim et al.

[DoomRulz]

That's probably why the line didn't go any further. The isotope analysis does suggest that the very last known spinosaurids didn't spend much time in water, and Spinosaurus in particular just wasn't well-adapted for a terrestrial lifestyle.

Was there further spinosaurid evolution beyond Spinosaurus?

Spinosaurus and poorly-known Brazilian giant Oxalaia were concurrently the last definite spinosaurids.
It's unclear how closely related the two were - Spinosaurus seemed to be an extremely long-lived genus, evolving right as the two landmasses split, but Oxalaia appeared 12 Ma after the split. It may be a relict Spinosaurus population, or it may be a massive baryonychine; hard to tell from a braincase and a scattering of teeth.

There are tooth finds attributed to spinosaurids for another 12 million years, but there's a history of spino teeth being confused with those of crocodilians, so they may not be valid. Spinosaurid evidence is generally extremely poor - it's basically just Baryonyx, Suchomimus, Irritator and Spinosaurus that are known in any significant detail.

I'm thinking that the Spinosauria will be like Tyrannosauria. It used to be that when people thought of the latter, they thought of T.Rex, Albertosaurus, Tarbosaurus, Daspletosaurus, and Nanotyrannus. Now it's expanded those (minus Nano) and includes Guanlong, Appalachiosaurus, Lythronax, and so on. I think the Spinosauria will eventually be the same with new discoveries.

That's probably why the line didn't go any further. The isotope analysis does suggest that the very last known spinosaurids didn't spend much time in water, and Spinosaurus in particular just wasn't well-adapted for a terrestrial lifestyle.

I don't expect Carcharodontosaurus would particularly want to get scrappy with Spinosaurus (the latest estimates I've heard are over 10 tonnes for the adults), but even if the spinos were able to scavenge food from other theropods, it'd be very hard for them to subsist on that alone.

Perhaps Spinosaurus primarily subsisted off of aestivating fish during the dry season (in fact, Andrea Cau, author of the theropoda blog, has posited the same hypothesis.).

If this is how it had to survive during droughts, I don't see Spino having a long life to live. Being able to get through drought would ultimately depend on how many fish (big ones to be exact) are sticking around year-round and not simply species that come and go as the seasons dictate. Have there been any studies on that?

Also, here's another researcher with some reservations about the new reconstruction from Ibrahim et al.

You and Vertigo are gonna love this. Parts of Spinosaurus may actually be a sauropod.

And for some fun,


Somewhere, a T.Rex is laughing.

[Gilfryd]

It's like a big wiener dog.

[OmegaZilla]

I just can't see an animal walking like that. Something from its arms should be more flexible than we think it is.

[DoomRulz]

It's come to light now that the arms are in fact composites, so this may yet change. As for flexibility, "opposable wrists" (I don't know what the correct terminology is) haven't been observed in any theropods so until we have original material, we have to assume they were stuck like that.

[OmegaZilla]

Not necessarily opposable wrists, but just more mobile wrists combined with a perhaps more versatile shoulder would already help the poor thing. Always more plausible than putting ALL that weight on its knuckles. They'd get kinda damaged in the long run.

[DoomRulz]

Not unless they were reinforced. They may have evolved to support all the weight, like a gorilla.

[King Rathalos]

It's like a big wiener dog.

heheh nerdiest dinosaur confirmed

[DoomRulz]

Here's a better GIF of it walking; one that doesn't disappear after half a second.