The two forms are indistinguishable in every diagnostic character, including the indentation of the anterior margin of the carapace. A unique feature of the Nicholson population, when only extant forms are considered, is the sigmoidal shape of the sulcus between the humerals and pectorals on the plastron (Figure 3a), this sulcus is straight in all other species of the Elseya dentata generic group. This feature is present in the holotype of Elseya lavarackorum (White & Archer, 1994) and in one (QM 30818) of the additional fossil specimens now available (Figure 3b). The anterior plastron is absent from the third fossil specimen (QM 30817).

     In contrast, the fossil has strongly embossed, rounded peripherals in the region adjacent to the bridge, a feature not present in the fifteen specimens from the Nicholson population. This is a similar condition to that found in aged, adult individuals in a number of species, i.e. individuals which are large for their species, such as Elusor macrurus (specimens over 400 mm), Elseya sp. aff. E. dentata from the Burnett River (specimens over 380 mm) and Emydura subglobosa from the Gregory and Reynolds Rivers (specimens over 250 mm). We consider this trait to be essentially a feature of large aged specimens in a range of chelid turtles. None of the turtles examined from the Nicholson drainage had carapace lengths in excess of 320 mm, well below the maximum size for species in the Elseya dentata generic group.