Genus: Polycotylus COPE, 1869
Etymology: Greek, polys, “much, many”, Greek, kotyle, “hollow, cup”, + us: Very cupped vertebrae.

Species: latipinnis COPE, 1869

Holotype: USNM 27678

Locality: 8 km east of Fort Wallace, on the Smokey Hill River, Logan County, Kansas.

Horizon: Smoky Hill Member, Niobrara Formation.

Biostratigraphy: Hesperornis zone.

Age: Santonian or Campanian Stage, Senonian Subepoch, Gulf Epoch, Late Cretaceous.

Material: Fragmentary skull and fragmentary skeleton.
Note: Gastroliths were found (WILLISTON, 1893, WHITTLE & EVERHART, 2000)