Genus: Sesimophis HSIOU, ALBINO, MEDEIROS, & SANTOS, 2014
Etymology: Greek, seism, "earthquake"; in allusion to the type locality Falesia do Sismito at Cajual Island, and Greek, ophis, "snake."

Species: septentrionalis HSIOU, ALBINO, MEDEIROS, & SANTOS, 2014
Etymology: Latin, Septentrionalis, from the north, northern, refering to the type locality, which is the northermost region of Maranhao.

Holotype: CPHNA-MA VT-1221

Locality: Falesia do Sismito, 2°28'43.0"S, 44°28'10.3"W, Cajual Island, Maranhao State, Brazil.

Horizon: Alcantrar Formation, Itapecuru Group.


Age: Cenomanian Stage, Upper Gallic subepoch, Lowest Gulf Epoch, Late Early to Early Middle Cretaceous.

Material: Almost complete posterior trunk vertebra.

Referred material:

= cf. Seismophis septentrionalis CPHNA-MA VT-1222: Incomplete mid-trunk vertebra.