Genus: Megacephalosaurus SCHUMACHER, CARPENTER, & EVERHART, 2013
Etymology: Greek, mega, "large or great," Greek, cephalo, "head" and Greek, sauros, "lizard."

Species: eulerti SCHUMACHER, CARPENTER, & EVERHART, 2013
Etymology: In honor of Otto C. Eulert, who graciously donated the specimen to the Fort Hays Kansas State College Museum (now Sternberg Museum of Natural History).
= Brachauchenius lucasi CARPENTER, 1996

Holotype: FHSM VP-321

Locality: Tributary of the Saline River valley, on land formerly owned by the O.C. Eulert Ranch, near the town of Fairport, Russell County, Kansas.

Horizon: Middle of the Fiarport Chalk Member, Carlile Shale (orignally states as the Jetmore or Pfeifer Member, Greenhorn Formation.)

Biostratigraphy: Collignoniceras wollgarti zone.

Age: Turonian Stage, Uppermost Gallic Subepoch, Lower Gulf Epoch, Late Cretaceous.

Material: Skull in dorsal view, mandibles, and anterior cervical vertebrae.

Paratype:

USNM 50136.

= aff. Brachauchenius lucasi SCHUMACHER, 2008

Locality: Unknown, Kansas? Western interior.

Biostratigraphy: Upper Greenhorn Formation or lowermost Fairport Chalk Member, Carlile Shale.

Biostratigraphy:

Age: Turonian Stage, Uppermost Gallic Subepoch, Lower Gulf Epoch, Late Cretaceous.

Material: Muzzle and palate of a partial skull, less the premaxillae, and includign nearly complete vomers, both maxillae, and portions of the pterygoids, palatines, jugals and right prefrontal.