TABLE 1 in Shell histology of the Triassic turtle, Proterochersis porebensis Szczygielski & Sulej, 2016, provides novel insights about shell ankylosis

TABLE 1. — Sectioned specimens of Proterochersis porebensis Szczygielski & Sulej, 2016. In the case of plastral bones, longitudinal sections follow the anteroposterior axis of the bone, as it was positioned in vivo. SpecimenDescriptionSizeReferencesZPAL V. 39/2Part of the carapace, sectioned transversely through the neurals (in two points, including the middorsal ridge) and longitudinally along the costalSmallSzczygielski et al. 2018: fig. S4A, BZPAL V. 39/9?Costal bone, sectioned transverselySmall–ZPAL V. 39/20Posterior costal bone without the overlying osteodermal mosaic, sectioned transverselyLargeSzczygielski & Sulej 2019: figs 12A, B, 13ZPAL V. 39/28Right tenth marginal + parts of the third and fourth pleural Middle-sized and eleventh marginal area, sectioned transversely through the costal (and, based on the location, likely the supernumerary dermal ossification; compare with 2) just above the pleuromarginal sulcus–ZPAL V. 39/61?Ninth marginal and third supramarginal area (peripheral and costal, possibly supernumerary carapacial ossification), sectioned transversely (longitudinally along the costal)Large–ZPAL V. 39/68Posterior part of the plastron (anal, intercaudal, and caudal scute areas) sectioned transversely through the caudal and intercaudal ossificationsMiddle-sizedSzczygielski & Sulej 2019: fig. 18G, H; Szczygielski et al. 2018: fig. 9HZPAL V. 39/195Plastral bone from the bridge region (?right first hyoplastron), sectioned longitudinallyMiddle-sized–ZPAL V. 39/388Anterior part of the plastron (gular and extragular projections), sectioned transverselySmall/middle-sizedSzczygielski et al. 2018: fig. S7K'–M'ZPAL V. 39/392?Posterior peripheral, sectioned obliquelyLarge–ZPAL V. 39/401Hyoplastron and posterior process of the entoplastron, sectioned transverselyLarge–ZPAL V. 39/416Neural bone, sectioned transverselyLargeSzczygielski & Sulej 2019: fig. 10C, DZPAL V. 39/417Supernumerary carapacial ossification (?third or fourth pleural boss), sectioned obliquelyMiddle-sizedSzczygielski & Sulej 2019ZPAL V. 39/476Plastral bone from the bridge region (?right hyoplastron), sectioned longitudinallySmall–ZPAL V. 39/477Costal bone, sectioned transverselyMiddle-sized(/large)–ZPAL V. 39/478Neural bone, sectioned transverselySmall(/middle-sized) –ZPAL V. 39/479Costal bone, sectioned transverselySmall–ZPAL V. 39/480Costal bone, sectioned transversely (two times) and longitudinally (two times)Middle-sized(/large)–ZPAL V. 39/482Nuchal region of the carapace, sectioned longitudinally through the nuchal and through dermal ossifications (peripheral and supernumerary osteoderms)Middle-sized–