Description External Morphology Carapace — The carapace is broadly oval slightly flattened at the anterior from the 2 nd marginal. The first vertebral scute is approximately the same width as the second. The outer sulci of the first vertebral tend to intersect the 2 nd marginal close to the sulcus between the 1 st and 2 nd marginal, differing from E. novaeguineae where it is in the center of the 2 nd marginal. There is some flaring of the marginal over the hind legs, though it tends to be more pronounced in E. novaeguineae and E. schultzei than is apparent in similarly sized individuals of E. rhodini. Cervical scute is present for all three taxa, though it is usually relatively narrower in E. rhodini than in the other two species of the subgenus. The carapace is brown in color for all three species, spots may be present at the center of each major scute, these persist into adult hood in E. rhodini, are faded if present in E. schultzei and may be absent altogether in E. novaeguineae. Plastron — The plastra of all three species are very similar, being rectangular in general shape but widest at the posterior of the anterior lobe and with lateral flanging in older individuals just anterior to the rear legs on the posterior lobe. The plastral formula is generally pec> fem> abd> ana> int> hum with the gulars excluded from the midline by the intergular. The plastron is cream to yellow in color, very occasionally there is a slight pink suffusion. Head and soft parts — The color of the sclera of E. rhodini is gold flecked green, 2.5 Y 7 / 8 to 2.5 Y 8 / 8 (Munsell 2000) with the iris gold and relatively indistinct. Compared with the color of the sclera of E. novaeguineae is green with no flecks, 5 y 7 / 3 to 5 y 8 / 3 (Munsell 2000) with a very distinct gold iris, and in E. schultzei it is also green with no flecks, 5 y 7 / 6 to 5 y 8 / 6 (Munsell 2000) again with a very distinct gold iris. The dorsal surface of the head of E. rhodini is variegated in color between yellow brown to dark brown, a similar pattern is seen in E. schultzei, however E. novaeguineae tends to be far less variegated without the striking patterns seen in the other species. Size and Sexual Dimorphism — This species attains a size of approximately 240 mm carapace length with females being slightly larger than males. This is similar for all members of the subgenus Hanwarachelys. The species attains a smaller adult size than Elseya branderhorsti with which it is sympatric throughout parts of its range. Osteology Skull (Figs. 11 – 13) — Dermal roofing elements of the skull are similar in all species of Elseya, the frontals are paired and the anterior process separates the nasals almost in their entirety. Parietals are large and postero-laterally suture to the squamosal to form the parietal arch. The arch is narrow in the Elseya (Elseya) much wider in Elseya (Hanwarachelys). This feature also determines the degree of lateral extension of the head shield as it requires bone for its support. On the palatal surface there are significant differences at the species level. The vomer of E. rhodini completely divides the maxillae anteriorly to meet the pre-maxillae and posteriorly the palatines to meet the pterygoids. In E. novaeguineae both the maxillae and palatines meet at the midline. In the description of Elseya (Pelocomastes) albagula (Thomson et al, 2006) the form of the alveolar ridge was further defined and we follow this here. The lingual ridge (sensu Thomson et al, 2006) is completely absent in all members of both Elseya (Elseya) and Elseya (Hanwarachelys) its presence being a synapomorphy for the Elseya (Pelocomastes). However the alveolar ridge is present in members of the Elseya (Elseya) and is only partially present in the members of Elseya (Hanwarachelys). In E. rhodini there is no obvious alveolar ridge on the ramphotheca of the upper jaw whereas there is a reduced, though present ridge consisting of a row of raised nodules in E. novaeguineae. Cervicals — The articulation formula is the same in all three species and follows the typical chelid condition of (2 (3 (4 (5) 6) 7 (8) (sensu Williams 1950). Shell — The carapace of members of the Elseya (Elseya) differ from members of the Elseya (Hanwarachelys) in the structure of the bridge strut suture, the former having a medial constriction, present in all three species, whereas this is absent in all members of the latter. Further the sutural scar of the ileum in the E. (Elseya) is separated from the anterior suture of the 8 th pleural with this scar occupying the posterior 2 / 3 of the 8 th pleural and continuing onto the pygal. In E. (Hanwarachelys) this scar is adjacent to the anterior suture of the 8 th pleural occupying the full width and also continuing on to the pygal (Figure 2). All members of the E. (Hanwarachelys) normally possess a cervical scute, absent in E. (Elseya) and E. (Pelocomastes). All three species of Elseya (Hawarachelys) lack exposed neural bones (sensu Thomson & Georges 1996) a feature common to the entire genus. There are slight differences in the general morphology of the shell between the three species within E. (Hanwarachelys), but subject to considerable within species variation.
