It lived during the Pennsylvanian (Missourian) in Kansas and possibly also Colorado[6] 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.
^R. R. Reisz, M. J. Heaton, and B. R. Pynn. 1982. Vertebrate Fauna of Late Pennsylvanian Rock Lake Shale near Garnett, Kansas: Pelycosauria. Journal of Paleontology 56(3):741-750
^F. E. Peabody. 1957. Pennsylvanian Reptiles of Garnett, Kansas: Edaphosaurs. Journal of Paleontology 31(5):947-949 [J. Mueller/T. Liebrecht]
^R. L. Carroll. 1988. Vertebrate Paleontology and Evolution 1-698 [A. Behrensmeyer/A. Behrensmeyer/M. Uhen]