Variation in the humeral-pectoral sulcus in extant Elseya lavarackorum from the Roper River, NT. A Specimen A112 shows the character state represented by the fossil holotype Elseya lavarackorum (sinusiodal sulcus sensu White and Archer 1994); B specimen A111 exhibits another variant of the humeral-pectoral sulcus; C specimen A110 shows the character state considered important by Joseph-Ouni et al. (2022); D specimen A106 shows the character state typical also of Elseya dentata. The character state of QMF30818 (inverted sinusoidal cf (a) lavarackorum, Fig. 4) is not represented in the specimens we have available. The character is not scorable in the partial plastron of QMF30817 (Fig. 3). This character state will have a substantial influence on the length of the interhumeral sulcus, and thus on all sulci characters that involve this length. Photos: Dion Wedd.