Genus: Opallionectes KEAR, 2006
Etymology: Greek, opallios, 'opal', and Greek, nektes, 'swimmer'; alluding to the holotype specimen's discovery in an opal mine an dreplacement of the fossil bone of opal.

Species: andamookaensis KEAR, 2006
Etymology: Combination of the type locality name Andamooka and latin, suffix, '-ensis'; referring to the derivation of the holotype specimen from near the opal-mining township of Andamooka.

Holotype: SAM P24560

Locality: Lunatic Hill opal field, near Andamooka, west of Lake Torrens, Eromanga Basin, north-eastern South Australia State, Australia.

Horizon: Bulldog Shale, Marree Subgroup.

Biostratigraphy: C. hughesii and C. striatus zones/O. operculata, D. davidii, and M. tetracantha zones.

Age: Lower Aptian-Lower Albian Stage, Middle Gallic Subepoch, Upper Early Cretaceous Epoch, Early Cretaceous.

Material: Teeth, 26 continous cervical, 3 pectoral and 10 dorsal vertebrae, separate caudal series of 16 vertebrae, associated ribs, gastralia, partial right scapula, fragment of left scapula, left and right coracoid, left humerus, radius, ulna, carpal and metacarpal elements, phalanges, right proximal humerus, right femur, 107 associated gastroliths.