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Re: Spinosaurus redescribed as giant semiaquatic theropod
With the upcoming NOVA/National Geographic special on Spinosaurus a
few weeks off, the Spinosaurnado may get a bit of a second wind.
Pending the monograph on the revised Spinosaurus, a couple of new blog
entries about some of the more controversial issues...
An alternative revised reconstruction of Spinosaurus with revised tail
and other details:
On Mon, Oct 6, 2014 at 7:21 PM, Tim Williams <firstname.lastname@example.org> wrote:
> dale mcinnes <email@example.com> wrote:
>> Didn't one spinosaurid specimen have the remains of an iquanodont inside its
>> rib cage ?? A vertebra or 2 ?? Crocs are piscivorous also but still take
>> terrestrial prey. But I am inclined to agree that spinosaurs were probably
>> more piscivorous than crocs even. Who knows ..
> Yes, we can only go where the evidence leads us. The _Baryonyx_
> holotype was found with remains of a small ornithopod as well as a
> fish (_Scheenstia_ - formerly _Lepidotes_) as stomach contents. The
> tooth of another spinosaurid was found embedded in a pterosaur
> vertebra, which suggests that pterosaurs were also part of the
> spinosaur diet - though (as with the other food items) it's not known
> if it was scavenged or predated. Other non-avian theropods have been
> found with fish as stomach contents (_Scipionyx_, _Microraptor_), as
> well as a number of Cretaceous avialans (including _Confuciusornis_).
> Based on their craniodental specializations, spinosaurids were likely
> to have been predominantly piscivorous. The postcranial skeletons of
> like _Baryonyx_ and _Suchomimus_ lack any obvious specializations for
> a semiaquatic or aquatic mode of life. _Spinosaurus_ is different
> (and more derived) in this respect.
> The obvious hypothesis is that spinosaurids ate fish as part of their
> diets, and that the lineage leading to _Spinosaurus_ began to spend
> more time in the water targeting aquatic prey, and thereby over time
> became more specialized for a semiaquatic lifestyle. It may be that
> the Kem Kem river system was particularly rich in large (and perhaps
> not particuarly fast) fishes and sharks, which promoted this
> specialization. We just don't know whether _Spinosaurus_ had close
> relatives (including descendents?) that took things further and became
> fully aquatic.
> I like Luis Rey's depiction of _Spinosaurus_ on the shore. Like him,
> I'm skeptical of _Spinosaurus_ (or any theropod) being capable of
> quadrupedal walking on land.
> But I'd be quite happy to see the future _Spinosaurus_ monograph
> refute this interpretation, and establish _Spinosaurus_ as a viable
> terrestrial quadruped when it ventured on to terra firma.