While excavating the specimens, the dig teams faced difficulty in removing the strata above the fossils, due to the presence of permafrost.

The cold temperatures also prevented the plaster from setting, so the teams used camp stoves and aluminium foil to heat it up, allowing it to harden.

They also found that the Texas Tech University collections from Seymour Island contain postcranial material from adult plesiosaurs that, while similar to Aristonectes, definitely belonged to a different taxon, further supporting the separation of the two genera.

[4] In a 2019 thesis, Elizabeth Lester assigned another specimen found by the expeditions that recovered the holotype of Morturneria seymourensis to the species.

Additionally, more material pertaining to the holotype was reported; a possible humeral head, an epipodial (lower limb bone), a possible carpal, and three phalanges.

[4] In 2003, Gasparini interpreted the M. seymourensis holotype as a juvenile because of its smaller size and the lack of fusion of the neural arches to the vertebrae.