Species: gracilis BROWN, 1914
Etymology: Latin, gracilis, "slender."
= Leptoceratops gravilis HUNT & LUCAS, 1992 (sic)
Holotype: AMNH 5205
Locality: 3 miles above the Tolman Ferry, 190 feet above the Red Deer River on the left bank, Wheatland County, Alberta Province, Canada.
Horizon: Scollard Formation, Uppermost Edmonton Group.
Biostratigraphy:
Age: Lancian Age, uppermost Maastrichtian Stage, uppermost Senonian subepoch, Upper Upper Gulf Epoch, Late Cretaceous.
Material: Nasals, maxillaries, portions of the orbital border, back part of crest, dentary, predentary and splenial, a series of articulated caudal vertebrae and a complete fore limb and parts of hind limb.
Quadrapedal pose.
Referred material:
RYAN & CURRIE, 1998
RTMP 93.95.1, 95.86.1: 2 partial skeletons.
OSTROM, 1978
Locality: Northwest of "Dumbbell Hill", Middle of SE 1/4, NW 1./4, SE 1/4, Sec. 1, T57N, R100W, Park County, Wyoming.
Horizon: "Lance" Formation.
Biostratigraphy:
Age: Lancian Age, uppermost Maastrichtian Stage, uppermost Senonian subepoch, Upper Upper Gulf Epoch, Late Cretaceous.
Material:
YPM 18133: Hind part of the skeleton, isolated tooth.
= Leptoceratops cf gracilis OTT & BUCKLEY, 2001, OTT, 2006Locality: Approximately 15 miles west of Camp Crook, South Dakota, and Carter County, Montana.
Horizon: Hell Creek Formation.
Biostratigraphy:
Age: Lancian Age, uppermost Maastrichtian Stage, uppermost Senonian subepoch, Upper Upper Gulf Epoch, Late Cretaceous.
Material:
UWGM-200: A partial skull.
Locality: University of Wisconsin site 2000-D, from the drainage basin of the Powder River, western Carter County, Montana.
Horizon: Hell Creek Formation.
Biostratigraphy:
Age: Lancian Age, uppermost Maastrichtian Stage, uppermost Senonian subepoch, Upper Upper Gulf Epoch, Late Cretaceous.
Material:
UWGM-201: A maxillary tooth with root.
STERNBERG, 1951
Locality: 14 miles north of the locality of the type, directly over Campkin's coal mine, in the Northeast corner of Sec. 12, T36, R22, W of 4 mer., about 1/3 1/2 miles northeast of Elnora, Red Deer County, Alberta Province, Canada.
Horizon: Scollard Formation, Uppermost Edmonton Group.
Biostratigraphy:
Age: Lancian Age, uppermost Maastrichtian Stage, uppermost Senonian subepoch, Upper Upper Gulf Epoch, Late Cretaceous.
Material:
Plesiotypes
NMC 8887: Complete articulated skeleton.
NMC 8888: Consist of skeleton, complete except most of skull and jaws and part of front foot.
Note: A skeleton has been found with a furcula.
TANKE, 2007
Locality: Hesketh, Alberta Province, Canada.
Horizon:
Biostratigraphy:
Age: Late Cretaceous.
Material:
RTMP 94.86.1: Fragmentary skeleton.
Locality: Dry Island Buffalo Jump Provincial Park, Wheatland County, Alberta Province, Canada.
Horizon: Scollard Formation, Uppermost Edmonton Group.
Biostratigraphy:
Age: Lancian Age, uppermost Maastrichtian Stage, uppermost Senonian subepoch, Upper Upper Gulf Epoch, Late Cretaceous.
Material:
RTMP 99.47.1: Scattered skeleton, feet, vertebrae, limb bones, rib fragments, part of articulated hips, tendons and pes.
Locality: Tolman Bridge, Wheatland County, Alberta Province, Canada.
Horizon: Scollard Formation, Uppermost Edmonton Group.
Biostratigraphy:
Age: Lancian Age, uppermost Maastrichtian Stage, uppermost Senonian subepoch, Upper Upper Gulf Epoch, Late Cretaceous.
Material:
RTMP 2005.8.1: Phalanges, ungual, centrum, ischium, bone fragments “limb elements”, and tooth.
Plesiotype:
NMC 8889Locality: Directly over Campkin's coal mine, 5 feet higher in the beds and less than 50 yards distinct from the above 2 specimens, in the Northeast corner of Sec. 12, T36, R22, W of 4 mer., about 1/3 1/2 miles northeast of Elnora, Alberta Province, Canada.
Horizon: Scollard Formation, Uppermost Edmonton Group.
Biostratigraphy:
Age: Lancian Age, uppermost Maastrichtian Stage, uppermost Senonian subepoch, Upper Upper Gulf Epoch, Late Cretaceous.
Material: Skull, jaws, presacral vertebrae, ribs, pectoral arches except upper ends of scapulae, left fore and hind limbs, sternal and hyoid bones.