Archaeologica.org

Spinous process in evolution

Here are three Wiki links:

Dimetrodon A Permian animal

Spinosaurus A Cretaceous animal

Bison Antiquus A Pleistocene animal

They all have a large spinous process. Is it coincidence, analogous, or do we just carry genes for this. Functionally, the first is considered to be a sail, the second is unknown, and the Bison is known.

I am definitely outside my knowledge and comfort zone here. Thoughts?

I'll take a guess on Spinosauros ..with that long head and neck perhaps they served as a muscle attachment. I'm thinking of the bison ..they have huge heads in relation to the rest of the body..youtube is full of videos of them launching the foolish yellowstone tourist who gets to close into the air with a mere flick of their head.

The one with the sail...well perhaps both ends of that creature were formidable weapons ..the tail and neck being about the same length...hence the symmetrical nature of the bony protrusions as muscle attachment points. I can see how if a creature where to use that rather large tail in a vertical slapping motion ...it would require that sort frame work.

Crocodiles have large tails and heads but do not have the spinal enlargement..why not...the crocs mostely use their tail in a sideways motion and mainly for propulsion..same with their head and necks..they either grab and roll or tear side to side..perhaps that accounts for their coke bottle shape..the major muscles being along the sides as opposed to say a bison.

talk about being out of your area of expertise....now if you want to set up an L shaped linear ambush or conduct a zone reconnaissance...I'm your guy