Genus: Estescincosaurus SULLIVAN, 1997
Etymology: Este, in honor of the late Richard Estes, Sinco, in reference to its scincomorph affinities and kind of lizard, and from Greek, sauros, “lizard”: Estes scincomorph lizard.
= Sauriscus ESTES 1964 non LAWRENCE, 1949 (Sauriscus ewingi, Arachnida, Trombiculidae, South African mite)
Etymology: Greek, sauriscus, "little lizard."

Species: cooki (ESTES 1964) SULLIVAN, 1997
Etymology: In honor of Dr. Harold J. Cook of Agate, Nebraska.
= Sauriscus cooki ESTES, 1964

Holotype: UCMP 49994

Locality: UCMP V-5620, Lull Quarry, near the head of a tributary of Buck Creek, Powder River Basin, Niobrara County (Formerly Converse County), Wyoming.

Horizon: Lance Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material: Complete left dentary.

Referred material:

UCMP 46088: Right maxilla, complete except for dorsal part of nasal process.

UCMP 47811: Fragment of left maxilla.

UCMP 47812: Fragment of left maxilla.

UCMP 47813: Anterior end of right dentary.

UCMP 47827: Almost complete right dentary.

UCMP 47828: Midsection of left dentary.

UCMP 47831: Almost complete left dentary.

UCMP 49995: Fragment of right maxilla.

UCMP 50017: Almost complete left dentary.

UCMP 50018: Almost complete right dentary, broken anteriorly and posteriorly.

UCMP 50019: Almost complete right dentary.