Xyrospondylus

Xyrospondylus is an extinct genus of non-mammalian synapsids belonging to the Edaphosauridae. The type species, X. ecordi, was named in 1982; it was originally named as a species of Edaphosaurus in 1957.

It lived during the Pennsylvanian (Missourian) in Kansas and possibly also Colorado and the holotype is known from a single cervical vertebra found in the Stanton Formation. A second specimen, consisting of a fragmentary pelvis, is also known. A third specimen, known from Colorado, is known, but it probably does not pertain to Xyrospondylus.