Bipedal or quadruped Spinosaurus

[anastasis008]

Following the debate about whether spinosaurus was quadruped and could actually swim and if it was bipedal and couldn't I came across a theory that S. aegyptiacus was bipedal and S. morrocanus was quadrupedal what are your thoughts on these theories?

[Misha]

Very interesting topic,

There is no way to know for sure at the moment but I think it would be cool to have a quadropedal theropod, and would make sense considering what we know about where it lived.

But even if this was the case I don't think it would be an obligate quadroped.

[anastasis008]

Ye

2 minutes ago, Misha said:

it would be cool to have a quadropedal theropod, and would make sense considering what we know about where it lived.

But even if this was the case I don't think it would be an obligate quadroped.

I agree, but what's  your opinion about the current spinosaurus that lived in Morocco, do you think it was bipedal or quadropedal?

[Misha]

4 minutes ago, anastasis008 said:

Ye

I agree, but what's  your opinion about the current spinosaurus that lived in Morocco, do you think it was bipedal or quadropedal?

I like the quadropedal idea

[Troodon]

On 7/8/2019 at 3:36 PM, anastasis008 said:

Following the debate about whether spinosaurus was quadroped and could actually swim and if it was bipedal and couldn't I came across a theory that aegyptiacus was bipedal and morrocanus was quadropedal what are your thoughts on these theories?

Current thinking is that Spinosaurus morrocanus is Nomen Dubium or jr synonym of S. aegyptiacus (of Egypt).   Until we get a more articulated skeleton from Morocco we cannot say if Sigilmassaurus or Spinosaurid sp.  are either Quad or Bi. or even aquatic

 

[Mark Kmiecik]

As far as swimming goes -- snakes have no legs and swim quite well. So do fish. It seems to me that the more legs an organism acquires, the less well it swims. It may live in water but doesn't swim well.

[anastasis008]

19 hours ago, Mark Kmiecik said:

the more legs an organism acquires, the less well it swims. It may live in water but doesn't swim well.

Yes but crocs and alligators have legs, short ones and when they swim they put them in their backs spinosaurus also had small legs so it may had been able to swim 

[LordTrilobite]

On 7/8/2019 at 10:10 PM, Troodon said:

Current thinking is that Spinosaurus morrocanus is Nomen Dubium or jr synonym of S. aegyptiacus (of Egypt).   Until we get a more articulated skeleton from Morocco we cannot say if Sigilmassaurus or Spinosaurid sp.  are either Quad or Bi. or even aquatic

 

Actually Spinosaurus maroccanus seems to be a junior synonym of Sigilmassasaurus brevicollis, not Spinosaurus aegyptiacus. The holotype of S. maroccanus has similar features to S. brevicollis like the ventral triangular rugose plateau on the cervical centra. Where it gets confusing is that there's also a snout attributed to S. maroccanus, but that specimen has recently been attributed to S. aegyptiacus.

 

 

Either way, there are no near complete skeletons known for either of these creatures. No associated arms have been found that are described. So we really cannot tell pretty much anything on if it could walk on four limbs. Based on other spinosaurids it seems likely that the arms wouldn't be weight bearing. But we really just don't know and nothing conclusive can be said about it at the moment.

[ynot]

On 7/8/2019 at 1:20 PM, Mark Kmiecik said:

the more legs an organism acquires, the less well it swims. It may live in water but doesn't swim well.

What about seals, otters, lizards, dugongs, frogs, salamanders and all them 6 legged water bugs?

[Mark Kmiecik]

16 hours ago, ynot said:

On 7/8/2019 at 3:20 PM, Mark Kmiecik said:

the more legs an organism acquires, the less well it swims. It may live in water but doesn't swim well.

What about seals, otters, lizards, dugongs, frogs, salamanders and all them 6 legged water bugs?

Thanks for proving my point. Fish and cetaceans swim well. If a fish or a cetacean can catch it and eat it then it does not swim well. Swimming efficiency decreases as number of legs increases. Consider millipedes. By your reasoning, with that many legs, it should swim very well. In reality it's pathetic. Seals don't really have legs, and are the most efficient of the group you mentioned, yet is no match for an orca speedwise. Agility, yes; speed, no. Frogs without legs -- tadpoles -- are more efficient swimmers. A human can swim at 5 mph and that makes Sirenians like dugongs seem fairly pathetic at only 13 mph. Lizards and amphibians are about as efficient as dugongs on the average with very few notable exceptions. Water bugs only use two of those six legs to propel themselves and so they swim at 33.3% efficiency.

 

I wasn't arguing the Spinosaurus's ability to swim. I was arguing it's efficiency. If it was evolving towards an amphibious existence it still had a long way to go, and would probably have spent most of its time on land. There's very little reason to spend much time in the water if you're going to be eaten there, and you have the option to stay on land.