Genus: Eothoracosaurus BROCHU, 2004
Etymolgy: Greek, eos, "dawn" in reference to its lower stratigrahpic position and more basal phylogenetic position relative to Thoracosaurus.

Species: mississippiensis BROCHU, 2004
Etymology: In reference to the state of Mississippi whee the holotype was found and to the Mississippi Embayment that evidently included part of the taxon's range.
= Thoracosaurus neocesariensis (de KAY, 1842) (partim)
= Thoracosaurus meirsanus CARPENTER, 1983

Holotype: MSU 3293

Locality: Oktiggeha County, Mississippi.
Note: Exact locality data on file at eh Dunn-Seller Museum Mississippi Sate University.

Horizon: Ripley Formation.

Biostratigraphy:

Age: Early Maastrichtian Stage? Upper Senonian Subepoch, Gulf Epoch, Late Cretaceous.

Material: Skull jaws, 4 cervicals, 11 dorsals, 2 sacral, 6 caudal vertebrae, left scapula, left and right coracoids, right ilium, left ischium, left and right femora, and approximately 45 scutes.

Referred material:

Locality: Sawhill Site Locality, Decatur County, Tennessee.

Note: Specific locality information available at Pink Palace Museum, Memphis.

Horizon: Coon Creek Tongue (possibly a member of the Ripley Formation).

Biostratigraphy:

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

Material:

PPM p2001.1.260: Posterior portion of skull including braincase.

Locality: 'Along Coon Creek', McNairy County, Tennessee.

Horizon: Coon Creek Tongue (possibly a member of the Ripley Formation).

Biostratigraphy:

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

Material:

AMNH 3841: Posteriormost portion of skull and incompletetly preparied anterior tip of lower jaw.

AMNH unnumbered: Tibia, 2 vertebrae and 3 partial osteoderms.

 

Locality: Georgia.

Horizon: Ripley Formation.

Biostratigraphy:

Age: Late Cretaceous.

Material:

USNM 5783: A partial mandible and single caudal vertebra.