Permian pelycosaur spines

[Othniel C. Marsh]

Are Permian "pelycosaur" spines diagnostic to a genus/species level?

[hadrosauridae]

The informal grouping of pelycosaurs involves quite a few different species, so yes, it is possible to distinguish many of them based on the vertebrae.  Some are very minor differences, especially of you only have the centra and cant see the neural process.  The centrums of Dimetrodon, Ophiacodon and Edaphasaurus are nearly identical, except for the keel at the bottom. 

[Othniel C. Marsh]

What features would one look for in neural spine fragments to distinguish the three aforementioned genera?

Edited Wednesday at 01:07 PM by Othniel C. Marsh

[hadrosauridae]

That really depends on the body location of the vert.  Caudal verts might be impossible, dorsal would be very obvious as Ddon has hyper-elongate, "barbell shaped" spines, Edaphosaurus as hyper-elongate spines with side protrusions, and Ophiacodon has short spines all the way along the back.  

[Othniel C. Marsh]

One final question (and probably the one I should have posed in the first place, but I wanted to try and ID them myself): do these look like Dimetrodon and Secodontosaurus neural spines?

 

 

Edited Wednesday at 02:24 PM by Othniel C. Marsh

[hadrosauridae]

The Dimetrodon spines look correct, but I have no experience with Secodontosaurus so I cant comment on those.

[Othniel C. Marsh]

Your help is much appreciated, @hadrosauridae.