Osteology

Skull. — Skull large and robust, emarginated both from below and behind (Fig. 4, n-5), but to a much lesser degree than E. dentata (sensu stricto) (n-12). Temporal emargination greater than in any other Queensland Elseya; parietal arch wider but not to the extent that it can support the attachment of a head shield. Alveolar ridge extensive, but not to the extent of E. lavarackorum (Fig. 8, n-2), beginning adjacent to the premaxilla lateral to the foramen praepalatinum. Alveolar ridge extends back to the end of the triturating surface; does not contact the palatines. Lingual ridge of the triturating surface heavily serrated and widened throughout its length; almost obscures the apertura nasalis interna and completely obscures the foramen praepalatinum from ventral view. The ridge extends back to almost make contact with the pterygoids but does not obscure the anterior edge of the vomer, differentiating it from E. lavarackorum. The lingual ridge is on the premaxilla in the anterior skull and continues onto the maxilla but adjacent to the medial edge of the apertura nasalis interna it continues onto the palatine bone. The degree of serrating is moderate but second only to E. lavarackorum in its widening of the triturating surface. The maxilla and palatines are significantly thickened and the apertura nasalis internae are deeply recessed into the palatal surface of the skull.

Vomer and the pterygoids not in contact; vomer not expanded posteriorly but separates the anterior two thirds of the palatines, a character that distinguishes this species from E. lavarackorum and E. sp. aff. dentata (Johnstone) (n-4) the vomer is expanded posteriorly in E. lavarackorum and only divides the anterior half of the palatines in E. sp. aff. dentata (Johnstone). Canalis caroticus internus closed. Foramen anterius canalis carociti interni absent.

      Ventral surface of the skull below the foramen nervi trigemini constricted to the same width as the braincase. In other Elseya this section is significantly wider than the braincase. Supraoccipital is extremely small dorsally, does not divide the parietals but lies posteriorly to them at the rear of the skull. Crista supraoccipitalis short, extending beyond the occipital condyle, but not to the same extent as in E. dentata.

Cervicals. — Articulation formula (Williams 1950) is the same as for all chelid turtles: (2(, (3(, (4(, (5), )6), )7(, (8). The atlas-axis complex (Hoffstetter and Gasc 1969) is made up of two neural arches and the first centrum ventrally and an intercentrum anteriorly, these units are fused as in the primitive condition for many turtle species. Centra of remaining cervicals have well-developed sagittal blades that are more prominent at the anterior end of the series and also at the anterior half of each centrum. Each sagittal blade straight in lateral view and narrow, except for the eighth cervical, which is markedly thickened. Transverse processes large, triangular, occupying the middle-third of the centrum and protruding horizontally from the neural arch; not angling downwards as in many other species. Postzygapophoses extremely large and almost joining in the midline; robust in overall structure. Prezygapophoses smaller and extending upwards to meet the postzygapophoses of the preceding vertebrae. Neural spine present but small.

Shell. — Anterior bridge buttress poorly developed (n-6). Anterior bridge strut suture with a widely spaced anterior and posterior component, a feature shared with E. lavarackorum (n-4), E. sp. aff. dentata (Johnstone) (n-4), and E. irwini (n-1); no prominent medial constriction. Posterior bridge strut well developed, in significant contact with the fifth pleural. Exposed neurals absent.

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