Genus: Syngonosaurus SEELEY, 1879 (nomen dubium; = Acanthopholis?)
Etymology: Greek, syngonos, “of the same parent, kindred” and Greek, sauros, “lizard”: “kindred lizard”.
= Sygmosaurus SAUVAGE, 1882 (sic)

Species: macrocercus SEELEY, 1879
Etymology: Greek, macro, "big" and Greek, cercus, "tail."
= Acanthopholis macrocercus SEELEY, 1869 (nomen nudum; in part)
= Anoplosaurus macrocercus (SEELEY, 1879) KUHN, 1964) (nomen dubium)
= Syngonosaurus macrourus HENNING, 1924 (sic)
= Syngonosaurus macromerus KUHN, 1936 (sic)
= Anoplosaurus macromerus KUHN, 1964 (sic)

Syntype: CAMSM B55570-78, B55580-86 (old Woodwardian Museum J g 1, SMC B55571-55579, B55582-55586).

Locality: Unknown, England, Southern United Kingdom.

Horizon: Cambridge Greensand Member, West Melbury Marly Chalk Formation (old Upper Greensand).

Biostratigraphy:

Age: Cenomanian Stage, Late Gallic Subepoch, Early Gulf Epoch, Middle Cretaceous

Material: 19 centra, consisting of 1 cervical, 9 dorsal, 3 sacral and 5 caudal centra, a humerus fragment, 2 phalanges.

Referred material:

LYDEKKER, 1888/1890

Locality: England.

Horizon: Cambridge Greensand.

Biostratigraphy:

Age: Late Albian Stage, Middle Gallic Subepoch, Upper Early Cretaceous Epoch, Early Cretaceous.

Material:

BMNH R460: Fragmentary dorsal vertebrae.

BMNH R460a: Fragmentary dorsal vertebra.

BMNH R460b: Fragmentary dorsal vertebra.

BMNH R460c: Fragmentary dorsal vertebra.

BMNH 46376: Centrum of a sacral vertebra.