Genus: Gwyneddosaurus BOCK, 1945 (nomen dubium)
Etymology: In reference to Gwynedd, Montgomery County, Pennsylvania and Greek, sauros, “lizard.”

Species: erici BOCK, 1945
Etymology:

Holotype: Academy of Natural Sciences 15072

Locality: Gwynedd, Montgomery County, Pennsylvania.

Horizon: Lockatong Formation, Newark Supergroup.

Biostratigraphy:

Age: Carnian Stage, Lower Late Triassic Epoch, Late Triassic.

Material: Pterygoid? scapula, coracoid, fragment of forelimb, tarsal, fragment of the foot bones, ribs, ilia, and vertebrae.

Note: Possibly Tanytrachelos.